Search

Processes driving the divergence of floral traits may be integral to the extraordinary richness of flowering plants and the assembly of diverse plant communities. Several models of pollinator-mediated floral evolution have been proposed; floral divergence may (i) be directly involved in driving speciation or may occur after speciation driven by (ii) drift or local adaptation in allopatry or (iii) negative interactions between species in sympatry. Here, we generate predictions for patterns of trait divergence and community assembly expected under these three models, and test these predictions in Hakea (Proteaceae), a diverse genus in the Southwest Australian biodiversity hotspot. We quantified functional richness for two key floral traits (pistil length and flower color), as well as phylogenetic distances between species, across ecological communities, and compared these to patterns generated from null models of community assembly. We also estimated the statistical relationship between rates of trait evolution and lineage diversification across the phylogeny. Patterns of community assembly suggest that flower color, but not floral phenology or morphology, or phylogenetic relatedness, is more divergent in communities than expected. Rates of lineage diversification and flower color evolution were negatively correlated across the phylogeny and rates of flower colour evolution were positively related to branching times. These results support a role for diversity-dependent species interactions driving floral divergence during the Hakea radiation, contributing to the development of the extraordinary species richness of southwest Australia., Evolution Letters, 5 (3)

Nutrient-poor ecosystems globally exhibit high plant diversity. One mechanism enabling the co-existence of species in such ecosystems is facilitation among plants with contrasting nutrient-acquisition strategies. The ecophysiological processes underlying these interactions remain poorly understood. We hypothesized that root positioning plays a role between sympatric species in nutrient-poor vegetation. We investigated how the growth traits of the focal mycorrhizal non-cluster-rooted Hibbertia racemosa change when grown in proximity of non-mycorrhizal Banksia attenuata, which produces cluster roots that increase nutrient availability, compared with growth with conspecifics. Focal plants were placed in the centre of rhizoboxes, and biomass allocation, root system architecture, specific root length (SRL), and leaf nutrient concentration were assessed. When grown with B. attenuata, focal plants decreased root investment, increased root growth towards B. attenuata, and positioned their roots near B. attenuata cluster roots. SRL was greater, and the degree of localized root investment correlated positively with B. attenuata cluster-root biomass. Total nutrient contents in the focal individuals were greater when grown with B. attenuata. Focal plants directed their root growth towards the putatively facilitating neighbour's cluster roots, modifying root traits and investment. Preferential root positioning and root morphological traits play important roles in positive plant-plant interactions.

BACKGROUND AND AIMS: Phosphorus (P) and nitrogen (N) are essential nutrients that frequently limit primary productivity in terrestrial ecosystems. Efficient use of these nutrients is important for plants growing in nutrient-poor environments. Plants generally reduce foliar P concentration in response to low soil P availability. We aimed to assess ecophysiological mechanisms and adaptive strategies for efficient use of P in Banksia attenuata (Proteaceae), naturally occurring on deep sand, and B. sessilis, occurring on shallow sand over laterite or limestone, by comparing the allocation of P among foliar P fractions. METHODS: We carried out pot experiments with slow-growing B. attenuata, which resprouts after fire, and faster growing opportunistic B. sessilis, which is killed by fire, on substrates with different P availability using a randomized complete block design. We measured leaf P and N concentrations, photosynthesis, leaf mass per area, relative growth rate and P allocated to major biochemical fractions in B. attenuata and B. sessilis. KEY RESULTS: The two species had similarly low foliar total P concentrations, but distinct patterns of P allocation to P-containing fractions. The foliar total N concentration of B. sessilis was greater than that of B. attenuata on all substrates. The foliar total P and N concentrations in both species decreased with decreasing P availability. The relative growth rate of both species was positively correlated with concentrations of both foliar nucleic acid P and total N, but there was no correlation with other P fractions. Faster growing B. sessilis allocated more P to nucleic acids than B. attenuata did, but other fractions were similar. CONCLUSIONS: The nutrient allocation patterns in faster growing opportunistic B. sessilis and slower growing B. attenuata revealed different strategies in response to soil P availability which matched their contrasting growth strategy.

In Australia, Phytophthora cinnamomi is the only species reported as the causal agent of stem canker and root rot in macadamia. In other countries, five Phytophthora species have been reported to cause diseases in macadamia, which led us to question if more than one Phytophthora species is responsible for poor tree health in macadamia orchards in Australia. To investigate this, samples were collected from the rhizosphere, stem, and root tissues of trees with and without symptoms, nurseries, and water sources from 70 commercial macadamia orchards in Australia. Phytophthora isolates were identified based on morphological characteristics and DNA sequencing. P. cinnamomi was the most predominant and widely distributed species, and was obtained from the different types of samples including symptomless root tissues. In addition to P. cinnamomi, only P. multivora was isolated from diseased tissue (stem canker) samples. Six other Phytophthora species were obtained from the rhizosphere samples: P. pseudocryptogea, P. citrophthora, P. nicotianae, P. gondwanense, P. sojae, and a new Phytophthora taxon. Only P. cinnamomi was obtained from macadamia nursery samples, while five Phytophthora species were obtained from water sources. Of the heterothallic Phytophthora species, mating type A2 isolates were dominant in P. cinnamomi isolates, whereas only mating type A1 isolates were obtained for P. nicotianae, P. pseudocryptogea, and P. citrophthora. Pathogenicity assays revealed that P. cinnamomi and P. multivora caused significantly larger stem and leaf lesions than P. citrophthora, P. nicotianae, and P. pseudocryptogea. Phytophthora sp. and P. sojae were nonpathogenic towards leaves and stems.

The Chilean hazelnut (Gevuina avellana Mol., Proteaceae) is a southern South American nut consumed as a snack and included in different preparations of traditional Chilean cuisine. Recently we described the fatty acid profile, oxylipins, phenolic compounds, as well as the antioxidant capacity. The main compounds of the phenolic-enriched extract were only tentatively identified by spectrometric means. In the present work, we describe the isolation and full characterization of a cyclic dipeptide cyclo(Arg-Trp) and other compounds from the phenolic enriched extracts of the G. avellana cotyledons. Compounds were isolated by means of counter-current chromatography and structures were established by spectroscopic and spectrometric methods. This is the first report on small peptides in G. avellana and adds evidence on the possible beneficial effects of this nut in human health.

Female plants not only flower but also produce resource-rich seeds, fruits, and cones. Thus, it is generally considered that female plants allocate more resources to sexual reproduction than male plants and that this allocation difference can explain vegetative dimorphism, such as greater leaf size in females. We found significant sexual vegetative differences in the dioecious and serotinous species, Aulax umbellata and A. cancellata. Plant height, annual branch length and canopy spread were greater in males whereas leaf size, branch thickness and branch number were greater in females. Sex ratios and basal stem area were, however, equal in the sexes. Equal sex ratios imply equal allocation to sexual reproduction and equal stem areas imply equal resource use and biomass, and thus allocation to vegetative growth. Given equal allocation to reproduction and resource use, we suggest that the vegetative dimorphism is driven by intra-male-competition to be more visually conspicuous to pollinators. This implies that plant architecture is both a vegetative and a reproductive trait.

Abnormal vertical growth (AVG) syndrome is a serious threat to the Australian macadamia industry as it decreases the yield of nuts by as much as 70% per annum. A lack of information on the cause of AVG has hindered the development of an effective disease management strategy. Discovery of genetic markers associated with disease resistance can be used as tool for rapid selection of elite cultivars, hence helps in efficient disease management. Differences in field susceptibility of macadamia cultivars provide an opportunity for discovery of genetic markers that are associated with host resistance. REML mixed model analysis was performed to estimate the AVG rating of 51 cultivars from multiple origins using phenotypic data from 359 trees planted in four sites. Most of the Hawaiian cultivars were found as susceptible, while selections from the Australian macadamia industry breeding program were predominantly resistant. All the cultivars were genotyped for 13,221 DArTseq-based single nucleotide polymorphism (SNP) markers. A bulked sample analysis was performed using 20 genotypes each at the extremes of AVG phenotypic ratings. Ten SNP markers were predicted to be associated with AVG resistance and two arbitrarily selected SNP markers were validated using PCR and Sanger sequencing. Our findings suggest that AVG resistance in the commercial cultivars may be derived from the genomic introgression of Macadamia tetraphylla through interspecific hybridization. The results may support marker-assisted selection for macadamia germplasm with AVG resistance.

The factors that influence seed production and seed dormancy in rare plant species are crucial to their conservation yet are often poorly understood. In this study, we examined the breeding system and seed biology of the critically endangered Australian endemic species Persoonia pauciflora through a series of experiments. Pollinator visitation surveys and manipulative hand-pollination treatments were conducted to investigate the breeding system and subsequent seed production. We used an experimental seed burial to examine the breakdown of the woody endocarp and changes to germination over time. Seed germination response under simulated local seasonal conditions was also examined. Persoonia pauciflora was found to be predominantly pollinated by native bees, and cross-pollinated flowers produced significantly more mature fruit (18 ± 3%) than self-pollination treatments (2–3%). The average strength of P. pauciflora pyrenes buried in soil significantly decreased over two years, from 413.3 ± 14.6 N to 130.8 ± 11.8 N. Post-burial seed germination was cyclical, with highest final germination percentage occurring following late-summer exhumations (75 ± 2% and 74 ± 14%, respectively). When seeds were incubated under different local seasonal conditions, germination at local summer temperatures was more likely when compared with autumn/spring and winter temperature-incubated seeds. Our study highlights the importance of ensuring appropriate biotic pollen vectors are present in the local landscape for maximising viable fruit production for this species. In addition, our data indicate that recruitment will most likely occur after the endocarp has suitably weakened, allowing physiological dormancy of the embryo to be relaxed and germination to commence following summer temperatures.

SUMMARY Fynbos is the dominant vegetation type in the Cape floristic region. Periodic fires are a natural phenomenon in fynbos and fire-stimulated seed germination has been reported for a number of fynbos species. Amongst the factors proposed as being directly responsible for the effects of fire are: heat fracturing hard seed coats, heat stimulating seed embryos, high-temperature desiccation of seed coats, ethylene and ammonia in smoke stimulating seed germination, and unknown chemical factors in plant-derived smoke and smoke extracts stimulating germination. In this study 28 fynbos species were screened for a seed germination response to smoke and/or smoke extract treatments. Twelve of these species showed a statistically significant enhancement of germination in response to treatment. For the first time smoke per se has been shown to act as a seed germination cue for fynbos species in the Asteraceae, Ericaceae and Restionaceae, and for the first time smoke extracts have been shown to enhance germination in fynbos species of Proteaceae. The most marked response to both smoke and smoke extracts was shown by seed of Syncarpha vestita (syn. Helichrysum vestitum) (Asteraceae).

SUMMARY Brandies of male and female plants of the dioecious Leucadendron rubrum Burm. f. were collected on the site of the Weikamp weather-station in the Jonkershoek State Forest, Stellenbosch, from July 1990 to September 1991. Xylem sap was extracted from the branches by vacuum extraction. HPLC was employed to purify the xylem sap and to separate the cytokinins prior to quantitation by ELISA. The cytokinin levels in the purified plant samples were determined using rabbit antiserum-based ELISAs for the determination of the levels of the cytokinins DHZR and IPA, and a trans-ZR specific monoclonal antibody-based ELISA for the determination of the levels of the cytokinin ZR. It was observed that the levels of the cytokinins DHZR and ZR did not differ significantly between male and female plants but did correlate with the seasonal growth patterns. The levels of the cytokinin IPA, in male and female plants of L. rubrum, not only correlated specifically with the different seasonal growth patterns observed but differed significantly between male and female plants. Peaks in the levels of all three cytokinins. i.e. ZR, DHZR and IPA, occurred during the study period. These peaks corresponded with the phenological development of L. rubrum, specifically with vegetative bud break and inflorescence differentiation and appeared to be synchronized with the growth and development. An attempt was also made to correlate cytokinin levels with the extreme differences in morphological characters exhibited by male and female plants, and possibly to explain to what extent these phytohormones influence sex expression in L. rubrum

Macadamia nuts, the seeds of Macadamia tetraphylla or Macadamia integrifolia of family Proteaceae, are a familiar food item. Previous case reports of macadamia nut allergy demonstrated the possibility of false negative IgE antibody test results and cross-reactivity of macadamia nut with hazelnut.1-5 However, the clinical features of childhood macadamia nut allergy and the cross-reactivity of macadamia nut with foods other than hazelnut remain understudied.

In pollination systems with a diverse community of floral visitors, qualitative and quantitative variations in pollination effectiveness can lead to a system in which higher effectiveness results from the synergetic contribution of multiple pollinators. By employing a series of field and laboratory experiments in the south Andes of Ecuador, we compared the effectiveness of hummingbirds and nocturnal mammals visiting Oreocallis grandiflora, an Andean member of the Proteaceae. Pollinator effectiveness was measured with a quantitative component that assessed visitation rates to inflorescences and number of contacted stigmas per visit, and with a qualitative component that counted the number of deposited pollen grains in stigmas. Effectiveness estimates were complemented with controlled pollination experiments that contrasted fruit and viable seed set among flowers exposed to either diurnal or nocturnal pollination, self-pollinated flowers, and a control group with flowers exposed to naturally occurring pollination. Four species of hummingbirds and two species of nocturnal mammals visited the flowers of O. grandiflora. Hummingbirds outperformed nocturnal mammals in the quantitative components of pollination, while mammals were more effective than hummingbirds in the qualitative component. Pollination success was higher for the control group than for the other treatments, while hummingbirds and mammals performed similarly. Our findings suggest a case of functional complementarity in pollination: hummingbirds’ quantitative effectiveness complements nocturnal mammals’ qualitative effectiveness. Furthermore, our study demonstrates that pollination success in plants can be greater when flowers are visited by the whole diversity of pollinators.

Phosphorus (P) deficiency induces cluster-root formation and carboxylate exudation in most Proteaceae. However, how external P supply regulates these root traits in Macadamia integrifolia remains unclear. Macadamia plants were grown hydroponically with seven P levels to characterize biomass allocation, cluster-root development, and exudation of carboxylates and acid phosphatases. Plant biomass increased with increasing P supply, peaking at 5 μM P, was the same at 5–25 μM P, and declined at 50–100 μM P. Leaf P concentration increased with increasing P supply, but shoot biomass was positively correlated with leaf P concentration up to 0.7–0.8 mg P g–1 dry weight (DW), and declined with further increasing leaf P concentration. The number of cluster roots declined with increasing P supply, with a critical value of leaf P concentration at 0.7–0.8 mg P g–1 DW. We found a similar trend for carboxylate release, with a critical value of leaf P concentration at 0.5 mg g–1 DW, but the activity of acid phosphatases showed a gradually-decreasing trend with increasing P supply. Our results suggest that leaf P concentration regulates the development and functioning of cluster roots, with a critical P concentration of 0.5–0.8 mg g–1, above which macadamia growth is inhibited.

Recent studies on patterns of biological invasions in several plant families have confirmed general findings (e.g., taxa with larger native range sizes are more likely to become invasive; and taxa with longer residence time in new regions are more likely to naturalise) and highlighted some context-specific findings relevant for management (e.g., resistance to Phytophthora is a pre-requisite for successful naturalisation in Proteaceae). We explore these issues for the plant family Myrtaceae, specifically by contrasting taxa with fleshy fruits with those with dry fruits to develop hypotheses around the role of seed dispersal in the invasion process. To this end we: 1) compiled a comprehensive list of introduced Myrtaceae; 2) determined the degree of establishment of each species in its introduced range; 3) compared the distribution of native, introduced, and invasive ranges; 4) assessed traits associated with the degree of establishment; and 5) assessed the magnitude and types of impacts of invasive Myrtaceae. A slightly higher proportion of dry-fruited species have been introduced than fleshy-fruited species [170 out of 2257 (7.5%) vs. 236 out of 3741 (6.7%)], though the difference was not significant. However, introduced dry-fruited Myrtaceae have naturalised more frequently than fleshy-fruited taxa [90 out of 170 (53%) vs. 40 out of 236 (17%)], whereas naturalised dry-fruited taxa have become invasive at a lower rate [22 out of 90 (24%) vs. 18 out of 40 (46%)]. Invasions of fleshy-fruited taxa seem to be more common on islands. Although invasions by fleshy- and dry-fruited species had similar impact mechanisms and magnitudes, naturalised fleshy-fruited Myrtaceae are more likely to have impacts on islands than dry-fruited confamilials. Synthesis Fleshy- and dry-fruited taxa of Myrtaceae differ in rate of transition along the invasion continuum and where invasions and impacts occur. We speculate that seed dispersal abilities, lack of competitors, and the availability of areas suitable for germination might explain these differences.

Background: South Africa is recognised as one of the most biodiverse countries in terms of fauna and flora in the sub-Saharan region. More than 40% of farmers in remote rural areas of the Eastern Cape Province use medicinal plants for the treatment of different livestock ailments. Aim: The aim of the study was to identify and document plant species used for the treatment of tick-borne diseases in the Amathole and O.R. Tambo district municipalities of the Eastern Cape, South Africa. Methods: Semi-structured questionnaire was employed to obtain detailed information of ethnoveterinary medicinal plants used including parts, mode of preparation and mode of administration from 48 respondents between November 2013 and February 2014. The collected plant species were identified scientifically at the Stutterheim Dohne Herbarium, where voucher numbers were obtained and herbarium specimens were deposited. Data collected were subjected to descriptive statistical analysis. Results: A total of nine medicinal plant species belonging to eight families and represented by nine genera were identified. The most dominant inhabitants were trees (55.6%), followed by herbs (33.3%) and shrubs (11.1%). The most frequently used plant families for tick-borne diseases were Xanthorrhoeaceae, Ebenaceae, Proteaceae, Malvaceae, Asteraceae, Vitaceae, Loganiaceae and Iridaceae, and from these plant families, leaves (44.4%) were the most commonly used plant parts. Conclusion: The data display that people in rural areas have preserved some knowledge of ethnoveterinary practices for the treatment of tick-borne diseases. However, further studies on plants used for the treatment of tick-borne diseases can be advanced towards validation and standardisation by evaluating parameters such as efficacy, safety and toxicity, quality (phytochemicals) and dosage standards.

Phosphorus (P) deficiency induces cluster-root formation and carboxylate exudation in most Proteaceae. However, how external P supply regulates these root traits in Macadamia integrifolia remains unclear. Macadamia plants were grown hydroponically with seven P levels to characterize biomass allocation, cluster-root development, and exudation of carboxylates and acid phosphatases. Plant biomass increased with increasing P supply, peaking at 5 μM P, was the same at 5–25 μM P, and declined at 50–100 μM P. Leaf P concentration increased with increasing P supply, but shoot biomass was positively correlated with leaf P concentration up to 0.7–0.8 mg P g–1 dry weight (DW), and declined with further increasing leaf P concentration. The number of cluster roots declined with increasing P supply, with a critical value of leaf P concentration at 0.7–0.8 mg P g–1 DW. We found a similar trend for carboxylate release, with a critical value of leaf P concentration at 0.5 mg g–1 DW, but the activity of acid phosphatases showed a gradually-decreasing trend with increasing P supply. Our results suggest that leaf P concentration regulates the development and functioning of cluster roots, with a critical P concentration of 0.5–0.8 mg g–1, above which macadamia growth is inhibited.

The postharvesting disorder leaf blackening is the main cause of product rejection in Protea during export. In this study, we report an investigation into metabolites associated with leaf blackening in Protea species. Methanol extracts of leaf and involucral bract tissue were analyzed by liquid chromatography hyphenated to photodiode array and high-resolution mass spectrometry (LC-PDA-HRMS), where 116 features were annotated. Analytical data obtained from 37 Protea species, selections, and hybrids were investigated using metabolomics tools, which showed that stems susceptible to leaf blackening cluster together and contained features identified as benzenetriol- and/or hydroquinone-derived metabolites. On the other hand, species, selections, and cultivars not prone to blackening were linked to metabolites with known protective properties against biotic and abiotic stressors. During the browning process, susceptible cultivars also produce these protective metabolites, yet at innately low levels, which may render these species and cultivars more vulnerable to blackening. Metabolites that were found to be correlated to the instigation of the browning process, all comprising benzenetriol- and hydroquinone-glycoside derivatives, are highlighted to provide preliminary insights to guide the development of new Protea cultivars not susceptible to leaf blackening.

We compared the use of phosphorus (P) and nitrogen (N) in slow-growing Banksia attenuata (Proteaceae), which resprouts after fire and naturally occurs on deep sand, with faster-growing opportunistic B. sessilis, which is killed by fire and occurs on shallow sand over laterite or limestone. We carried out pot experiments with plants on substrates with different P availability. We measured foliar nutrient concentrations, and P allocated to major biochemical fractions. The two species had similar foliar total P concentrations, but distinct patterns of P allocation to P-containing fractions. The foliar total N concentration of B. sessilis was greater than that of B. attenuata on all substrates. The foliar total P and N concentrations in both species decreased with decreasing P availability. The relative growth rate of both species was positively correlated with both foliar nucleic acid P and total N concentrations, but there was no correlation with other P and N fractions. Faster-growing B. sessilis allocated more P to nucleic acids than B. attenuata did, but other fractions were similar. We conclude that the nutrient-allocation patterns in faster-growing opportunistic B. sessilis and slower-growing B. attenuata revealed different strategies in response to soil P availability, which matched their contrasting growth strategy.

Fruits of Gevuina avellana (Proteaceae) seem to mimic wasp-induced galls of Nothofagus dombeyi (Nothofagaceae) to escape predation by rodents, which may change both spatially and temporarily. The objective of this study was to evaluate the similarity between the fruits of G. avellana and the galls of N. dombeyi and to determine if this similarity protects fruits from predation by rodents in a disturbed temperate forest. We evaluated: i) the similarity between fruits and galls by measuring length, diameter, weight and color; and ii) the effects of galls on fruit predation by offering them to rodents in varying proportions, in a forest and a meadow, over two years. Fruits and galls showed similar phenotypes but fruits were more consumed than galls, even at low fruit frequencies, suggesting that their similarities are not due to mimicry. Fruits escaped predation more in the meadow than in the forest, particularly during the second year, thus indicating spatio-temporal variability in the phenomenon. The similarity between fruits and galls seems to be the result of phylogenetic and/or developmental constraints, rather than the result of a Darwinian coevolutionary pathway mediated by rodents. However, mimicry may happen with other dry-fruited plants inhabiting deforested habitats, which encourages further studies.

International audience; Organisms have evolved a diversity of life-history strategies to cope with variation in their environment. Persistence as adults and/or seeds across recruitment events allows species to dampen the effects of environmental fluctuations. The evolution of life cycles with overlapping generations should thus permit the colonization of environments with uncertain recruitment. We tested this hypothesis in Leucadendron (Proteaceae), a genus with high functional diversity native to fire-prone habitats in the South African fynbos. We analyzed the joint evolution of life-history traits (adult survival and seed-bank strategies) and ecological niches (climate and fire regime), using comparative methods and accounting for various sources of uncertainty. In the fynbos, species with canopy seed banks that are unable to survive fire as adults display nonoverlapping generations. In contrast, resprouters with an underground seed bank may be less threatened by extreme climatic events and fire intervals, given their iteroparity and long-lasting seed bank. Life cycles with nonoverlapping generations indeed jointly evolved with niches with less exposure to frost but not with those with less exposure to drought. Canopy seed banks jointly evolved with niches with more predictable fire return, compared to underground seed banks. The evolution of extraordinary functional diversity among fynbos plants thus reflects, at least in part, the diversity of both climates and fire regimes in this region.

Rodents are important pollinators and seed predators of fynbos Proteaceae, but their role as florivores has received little attention. Chacma baboons (Papio hamadryas ursinus) are known to feed on Proteaceae inflorescences, however, their effect on plant reproduction has not been quantified. We recorded the extent of damage by rodents and baboons to inflorescences of the dominant shrub, Protea neriifolia, in 20 × 20 m plots in the Jonkershoek Nature Reserve near Stellenbosch. Damage was distributed patchily across the landscape. Rodents damaged up to 23% of the inflorescences per plot by feeding on styles and nectar. We observed the striped mouse (Rhabdomys pumilio) climbing up plants to feed on inflorescences. Up to 14% of inflorescences in some plots were destroyed by rodents gnawing through inflorescence stems. Baboons damaged or destroyed 12% to 29% of inflorescences at three study sites, but did not forage at all in the three remaining study sites. Among plant individuals affected by baboons or rodents, a mean proportion of 0.49 ± 0.31 (SD) of individuals' inflorescences were damaged or destroyed. Florivory by rodents and baboons can thus reduce the fecundity of P. neriifolia significantly. Protea inflorescences may be an important seasonal food source for certain rodents. In an evolutionary context, rodent florivory may have been an important selective force that caused certain Proteaceae species to shift to rodent pollination. Further work is needed to determine which rodent species feed on Protea inflorescences and whether rodent florivory is widespread in fynbos.

Hakea prostrata R.Br. (Proteaceae) shows a ‘delayed greening’ strategy of leaf development characterised by reddish young leaves that become green as they mature. This trait may contribute to efficient use of phosphorus (P) during leaf development by first investing P in the development of leaf structure followed by maturation of the photosynthetic machinery. In this study, we investigated the properties of delayed greening in a highly P-efficient species to enhance our understanding of the ecological significance of this trait as a nutrient-saving and photoprotective strategy. In glasshouse-grown plants, we assessed foliar pigments, fatty acids and nutrient composition across five leaf developmental stages. Young leaves had higher concentrations of anthocyanin, P, nitrogen (N), copper (Cu), xanthophyll-cycle pigments and saturated fatty acids than mature leaves. As leaves developed, the concentration of anthocyanins decreased, whereas that of chlorophyll and the double bond index of fatty acids increased. In mature leaves, ~60% of the fatty acids was α-linolenic acid (C18:3 n-3). Mature leaves also had higher concentrations of aluminium (Al), calcium (Ca) and manganese (Mn) than young leaves. We conclude that delayed greening in H. prostrata is a strategy that saves P as well as N and Cu through sequential allocation of these resources, first to cell production and structural development, and then to supplement chloroplast development. This strategy also protects young leaves against photodamage and oxidative stress during leaf expansion under high-light conditions.

Background and Aims Floral chemical defence strategies remain understudied despite the significance of flowers to plant fitness, and the fact that many flowers contain secondary metabolites that confer resistance to herbivores. Optimal defence and apparency theories predict that the most apparent plant parts and/or those most important to fitness should be most defended. To test whether within-flower distributions of chemical defence are consistent with these theories we used cyanogenic glycosides (CNglycs), which are constitutive defence metabolites that deter herbivores by releasing hydrogen cyanide upon hydrolysis. Methods We used cyanogenic florets of the genus Lomatia to investigate at what scale there may be strategic allocation of CNglycs in flowers, what their localization reveals about function, and whether levels of floral CNglycs differ between eight congeneric species across a climatic gradient. Within-flower distributions of CNglycs during development were quantified, CNglycs were identified and their localization was visualized in cryosectioned florets using matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). Key Results Florets of all congeneric species studied were cyanogenic, and concentrations differed between species. Within florets there was substantial variation in CNglyc concentrations, with extremely high concentrations (up to 14.6 mg CN g−1 d. wt) in pollen and loose, specialized surface cells on the pollen presenter, among the highest concentrations reported in plant tissues. Two tyrosine-derived CNglycs, the monoglycoside dhurrin and diglycoside proteacin, were identified. MALDI-MSI revealed their varying ratios in different floral tissues; proteacin was primarily localized to anthers and ovules, and dhurrin to specialized cells on the pollen presenter. The mix of transient specialized cells and pollen of L. fraxinifolia was ~11 % dhurrin and ~1.1 % proteacin by mass. Conclusions Tissue-specific distributions of two CNglycs and substantial variation in their concentrations within florets suggests their allocation is under strong selection. Localized, high CNglyc concentrations in transient cells challenge the predictions of defence theories, and highlight the importance of fine-scale metabolite visualization, and the need for further investigation into the ecological and metabolic roles of CNglycs in floral tissues.

Several tree crops have experienced rapid increase in yield per hectare due to the application of high-density planting systems and increased understanding of plant architecture. Macadamia, as a less-developed tree crop, may benefit from similar improvement. Macadamia species are evergreen sub-tropical trees of the family Proteaceae, native to the mid-eastern coast of Australia. The genus Macadamia is comprised of four species: Macadamia integrifolia, M. tetraphylla, M. jansenii and M. ternifolia, which vary in tree size and yield. Commercial macadamia tree canopies are relatively unmodified from their natural form and are currently managed by crude hedging that can result in yield loss. Canopy growth is dense and vigorous, which historically has been addressed by planting orchards at low-density.In an effort to make higher planting densities possible, this thesis determines the diversity of plant architecture in macadamia and establishes the role of plant architecture in the improvement of yield efficiency for future macadamia cultivars and orchard systems. The research details how vegetative and reproductive architecture is organised in macadamia and how traits at different scales of growth interact to produce outcomes in overall canopy size, structure and yield. Phenotypic relationships between vegetative architecture and yield components were investigated in order to understand the dynamics of structure and function. The study found a high level of diversity in architectural traits and yield components across a range of macadamia genotypes. Architectural traits that showed potential for commercial importance were identified. A positive relationship between branch angle and flowering was apparent across studies, as was a negative relationship between branch angle and apical vigour. On young trees, flowering tended to occur on the most-apical flushes. Raceme length related positively with yield, whereas TCA and branch unit length related positively with canopy volume. Identification of these multi-scale relationships provides new opportunities for controlling vigour and potentially increasing yield in future systems via modification of specific traits.Modification of such architectural traits is vital to the improvement of productivity and to the suitability of future cultivars for high-density planting. Limb bending experiments in six-year-old trees suggested that bending shoots in May increased local flowering, whereas bending at other times increased lateral growth and decreased apical growth but not flowering. Continuous limb bending over the early years of growth in another experiment did not significantly influence flowering or yield. Breeding desirable architectural traits may be a more practical solution to management of canopy architecture. Heritability calculations suggested that genetic gain would be slow when breeding directly for yield and canopy volume, however, a number of multi-scale architectural (trunk cross-sectional area; branch angle; node number per GU) and yield components (raceme length; raceme number) showed high heritability. These traits showed strong genetic relationships with yield and tree size, proposing useful focus traits for indirect breeding to increase genetic gain. This research emphasises the importance of breeding new cultivars for the macadamia industry and the protection of untapped diversity in natural macadamia populations. Viability of the intensification of macadamia is discussed alongside considerations for manipulation of canopy architecture for increased productivity.

The genus Grevillea (family Proteaceae) comprises over 300 species and is a popular and widely cultivated group of Australian plants. In the last 3 years, numerous potted grevilleas with symptoms of decline associated with a rot of feeder roots were found in ornamental nurseries in Sicily. Aboveground symptoms were reduced growth, yellowing of foliage, wilt, dieback, and death of the entire plant. The disease was observed on many commercial cultivars and was especially severe on G. alpina (mountain grevillea), G. juniperina (juniper-leaf grevillea), G. lavandulacea (lavender grevillea), and G. rosmarinifolia (rosemary grevillea) as well as the hybrid cultivars Clearview David (G. lavandulacea × rosmarinifolia) and Poorinda Rondeau (G. baueri × lavandulacea), while G. lanigera (woolly grevillea) cv. Mount Tamboritha and G. thelemanniana subsp. obtusifolia appeared resistant. A species of Phytophthora was consistently isolated from rotted roots of symptomatic plants using a selective medium (4), and pure cultures were obtained by single-hypha transfers. The species was identified as P. palmivora (E.I. Butler) E.I. Butler on the basis of morphological and cultural characters. On solid media, all isolates produced elliptical to ovoid, papillate sporangia with a mean length/width ratio of 1.8. Sporangia were caducous with a short pedicel (5 μm) and a conspicuous basal plug. All isolates were heterothallic (mating type A1) and produced oogonia and oospores only when paired with A2 mating type reference isolates of P. nicotianae and P. palmivora. Antheridia were amphyginous. Identification was confirmed by electrophoresis of mycelial proteins in polyacrylamide slab gels (1). The electrophoretic patterns of total soluble proteins and six isozymes (alkaline phosphatase, esterase, fumarase, NAD-glucose dehydrogenase, malate dehydrogenase, and superoxide dismutase) of isolates from grevillea were identical to those of a reference isolate of P. palmivora from Coronilla valentina subsp. glauca (2) but distinct from those of reference strains of eight other papillate species of Phytophthora included in Waterhouse's taxonomic group VI. Koch's postulates were fulfilled using 6-month-old rosemary grevillea plants that were transplanted into pots filled with soil that was artificially infested with chlamydospores (50 per gram of soil) produced in submerged cultures (3) by grevillea isolate IMI 390579. Plants were maintained in a glasshouse at 20 to 28°C and watered to field capacity once a week. One month after transplanting, infected plants showed decline symptoms similar to those of naturally infected plants. Control plants grown in pots containing noninfested soil remained healthy. P. palmivora was reisolated from roots of symptomatic plants. It appears that P. palmivora has become a widespread root pathogen in commercial ornamental nurseries in Italy (2). References: (1) S. O. Cacciola et al. EPPO Bull. 20:47, 1990.D. (2) S. O. Cacciola et al. Plant Dis. 86:327, 2002. (3) J. Y. Kadooka and W. H. Ko. Phytopathology 63:559, 1973. (4) H. Masago et al. Phytopathology 67:425, 1977.

Identifying the geographic origins of crops is important for the conservation and utilization of novel genetic variation. Even so, the origins of many food crops remain elusive. The tree nut crop macadamia has a remarkable domestication history, from subtropical rain forests in Australia through Hawaii to global cultivation all within the last century. The industry is based primarily on Macadamia integrifolia and M. integrifolia–M. tetraphylla hybrid cultivars with Hawaiian cultivars the main contributors to world production. Sequence data from the chloroplast genome assembled using a genome skimming strategy was used to determine population structure among remnant populations of the main progenitor species, M. integrifolia. Phylogenetic analysis of a 506 bp chloroplast SNP alignment from 64 wild and cultivated accessions identified phylogeographic structure and deep divergences between clades providing evidence for historical barriers to seed dispersal. High levels of variation were detected among wild accessions. Most Hawaiian cultivars, however, shared a single chlorotype that was also present at two wild sites at Mooloo and Mt Bauple from the northernmost distribution of the species in south-east Queensland. Our results provide evidence for a maternal genetic bottleneck during early macadamia domestication, and pinpoint the likely source of seed used to develop the Hawaiian cultivars. The extensive variability and structuring of M. integrifolia chloroplast genomic variation detected in this study suggests much unexploited genetic diversity is available for improvement of this recently domesticated crop.

International audience; Proteaceae are a basal eudicot family with a highly conserved floral groundplan but which displays considerable variation in other aspects of floral and inflorescence morphology. Their morphological diversity and phylogenetic position make them good candidates for understanding the evolution of floral architecture, in particular the question of the homology of the undifferentiated perianth with the differentiated perianth of core eudicots, and the mechanisms underlying the repeated evolution of zygomorphy. In this paper, we combine a morphological approach to explore floral ontogenesis and a transcriptomic approach to access the genes involved in floral organ identity and development, focusing on Grevillea juniperina, a species from subfamily Grevilleoideae. We present developmental data for Grevillea juniperina and three additional species that differ in their floral symmetry using stereomicroscopy, SEM and High Resolution X-Ray Computed Tomography. We find that the adnation of stamens to tepals takes place at early developmental stages, and that the establishment of bilateral symmetry coincides with the asymmetrical growth of the single carpel. To set a framework for understanding the genetic basis of floral development in Proteaceae, we generated and annotated de novo a reference leaf/flower transcriptome from Grevillea juniperina. We found Grevillea homologs of all lineages of MADS-box genes involved in floral organ identity. Using Arabidopsis thaliana gene expression data as a reference, we found homologs of other genes involved in floral development in the transcriptome of G. juniperina. We also found at least 21 class I and class II TCP genes, a gene family involved in the regulation of growth processes, including floral symmetry. The expression patterns of a set of floral genes obtained from the transcriptome were characterized during floral development to assess their organ specificity and asymmetry of expression.

Grevillea papuana is a culturally important endemic plant species of New Guinea highland. Although G. papuana conservation and propagation attempts were already conducted, this species seed and germination characters information were still very limited. This study aimed to provide information regarding G. papuana seed and germination biology. Seed characteristic and germination trials were conducted in this study. Data analysis was conducted descriptively, while germination parameters were also calculated. G. papuana has a light, elliptic, and winged seed. The species germination was low and ununiform with phanerocotylar epigeal foliaceous (PEF) seedling functional type.

• Disruption of pollination services has been investigated in many species; however, fragmentation-induced effects on endemic plants that rely on species-specific invertebrate pollinators are still unclear. While honeybees can forage over long distances, many native bees with small body size are unable to extend their foraging range, making habitat fragmentation the largest threat to such systems. • Here, we defined the pollinator assemblage of our target species, Conospermum undulatum (Proteaceae), among remnant populations characterized by different degrees of fragmentation. We explored the impact of fragmentation on flower visitation in eleven populations of C. undulatum. Lastly, we took advantage of the fragmentation gradient to tease apart the influences of pollen quantity and quality on pollen limitation. • Small populations showed an impoverished pool of weakly effective pollinators. Flower visitation increased from 1.5% to 74.3% with increasing floral display index, while it increased from 1.3% to 5.6% with increasing connectivity levels of populations. We found evidence of pollen quantity limitation across all the populations; however, the overall pollen limitation was greater in small fragments where genetic factors limited the quality of pollen. • Native bees were absent in small isolated remnants. Our study highlights the importance of such pollinators for plants that coevolved with them. The availability of compatible pollen is limited in small remnant populations and native pollinators appeared unable to maintain an adequate inter-population pollen flow in heavily fragmented landscapes. The effects of habitat fragmentation can be exacerbated in small and isolated populations of plants that rely on species-specific pollinators for sexual reproduction.

Vegetation structure and plant species diversity of restoration sites are predicted to directly affect pollinator attraction, with potential impacts on gene flow, reproduction, genetic diversity of future generations, and ultimately restoration success. We compared Banksia attenuata R.Br. (Proteaceae) in a low species diversity restoration site and an adjacent natural remnant. We assessed fecundity genetic diversity in adult plants and their offspring, mating system parameters and pollen dispersal using paternity assignment. Results were compared to an earlier study of reproductive functionality within a high species diversity restoration site that was restored in a similar manner, enabling us to investigate any association between plant species diversity and fecundity. Seed set data indicated no significant differences between restored and adjacent natural sites; however, seed set data between restoration sites was significantly different (2.08 ± 0.39 and 6.89 ± 1.12, respectively). The mean number of fruits (follicles) per inflorescence was not significantly different between restoration sites. Genetic diversity of adult plants and their offspring were comparable in all sites. Higher allelic richness and genetic differentiation in one restored site reflected sourcing beyond local provenance. Low correlated paternity indicated high levels of multiple siring of seeds and paternity assignment demonstrated strong genetic connectivity between sites. Reproductive functionality, as measured by fecundity and genetic diversity in the offspring of B. attenuata, is resilient to low species diversity within a restored plant community. We consider our results in the context of establishing seed production areas (SPAs) that maximize the quantity and genetic quality of Banksia seeds for restoration.

Soilborne pathogens can contribute to the maintenance of local plant diversity by reducing differences in competitive ability between co-occurring plant species. It has been hypothesized that efficient phosphorus (P) acquisition by plants in P-impoverished ecosystems might trade off against resistance to root pathogens. This could help explain high plant diversity in severely nutrient-impoverished ecosystems. However, empirical evidence of such a trade-off remains scarce. In hyperdiverse shrublands in south-western Australia, non-mycorrhizal cluster-rooted Proteaceae are very efficient at acquiring P. However, Proteaceae co-occur with many other plant species using other P-acquisition strategies, such as ectomycorrhizal (ECM) associations. In a glasshouse experiment, we grew Proteaceae and ECM plant species from hyperdiverse shrublands alone and in competition with each other, and in the presence or absence of native soilborne pathogens (Phytophthora spp.). We hypothesized that native Phytophthora species are more detrimental to Proteaceae than co-occurring ECM plants, due to a trade-off between highly efficient P-acquisition and pathogen defence, and that this equalizes differences in competitive ability between these two plant groups. When seedlings were grown alone, biomass of non-mycorrhizal plants was reduced in the presence of Phytopthora, while ECM species were unaffected by this pathogen. When non-mycorrhizal and ECM species were planted together, ECM plants grew better in the presence of Phytophthora than in its absence, because Phytophthora reduced the growth of the non-mycorrhizal competitors. Growth of ECM plants was positively correlated with per cent root colonization by ECM fungi, but this was only significant when ECM plants were grown in the presence of Phytophthora. Synthesis. Our study shows that native soilborne pathogens equalized differences in competitive ability between seedlings of contrasting nutrient-acquisition strategies, thus supporting the hypothesis proposing a trade-off between highly efficient P-acquisition and resistance against root pathogens. We found that non-mycorrhizal cluster-rooted species may be the most efficient at acquiring the growth-limiting resource, but that co-occurring ECM species are better defended against root pathogens. Our results suggest that native soilborne pathogens and ECM contribute to the maintenance of the plant hyperdiversity in severely P-impoverished ecosystems.

Persoonia longifolia is a common mid-storey species that is difficult to return to post-mining environments. This study aimed to quantify in situ emergence of P. longifolia seeds on restored areas, investigate seed cueing prior to use in restoration and assess different tree guards for increasing seedling survival and health. Initial investigations found that

Despite the abundance of serotinous species in southwestern Australia, demonstration of the enhancement of fitness through fire, by releasing seeds onto an optimal postfire seedbed for seedling establishment, rather than following drought death, has not been explicitly explored. In this study, we measured seed release, germination and seedling recruitment following plant death after fire and simulated drought among six serotinous species in southwestern Australia. Burning or heating the cones/fruits resulted in a marked increase in follicle opening (pyriscence) compared with plant death from drought (necriscence) among Banksia but not Hakea. We recorded higher rates of germination, lower seedling mortality and better seedling growth in the post-fire environments than in unburnt sites not burnt for at least 10 years for five species (seeds of the sixth species were non-viable). Seedling mortality among the five species of 100 % occurred in the unburnt plots over the first summer, while 28–79 % of seedlings survived in the burnt plots. Soil moisture measurements indicated much lower water availability in the unburnt sites even in spring. Our study provides strong empirical evidence that serotiny/pyriscence enhances species fitness by releasing seeds into an optimal post-fire habitat in contrast to that observed from plant/crown death due to drought. In the context of the long history of fire in southwestern Australia, the greatly enhanced fitness in response to fire rather than severe drought supports the proposition that serotiny is a specific adaptation to fire.

Heteroblasty, the temporal development of the meristem, can produce diverse leaf shapes within a plant. Gevuina avellana, a tree from the South American temperate rainforest shows strong heteroblasty affecting leaf shape, transitioning from juvenile simple leaves to highly pinnate adult leaves. Light availability within the forest canopy also modulates its leaf size and complexity. Here we studied how the interaction between the light environment and the heteroblastic progression of leaves is coordinated in this species. We used RNA-seq on the Illumina platform to compare the range of transcriptional responses in leaf primordia of G. avellana at different heteroblastic stages and growing under different light environments. We found a steady up-regulation of SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL), NAC, YUCCA and AGAMOUS-LIKE genes associated with increases in age, leaf complexity, and light availability. In contrast, expression of TCP, TPR and KNOTTED1 homeobox genes showed a sustained down-regulation. Additionally, genes involved in auxin synthesis/transport and jasmonate activity were differentially expressed, indicating an active regulation of processes controlled by these hormones. Our large-scale transcriptional analysis of the leaf primordia of G. avellana sheds light on the integration of internal and external cues during heteroblastic development in this species.

Transitions between animal and wind pollination have occurred in many lineages and have been linked to various floral modifications, but these have seldom been assessed in a phylogenetic framework. In the dioecious genus Leucadendron (Proteaceae), transitions from insect to wind pollination have occurred at least four times. Using analyses that controlled for relatedness among Leucadendron species, we investigated how these transitions shaped the evolution of floral structural and signaling traits, including the degree of sexual dimorphism in these traits. Pollen grains of wind-pollinated species were found to be smaller, more numerous, and dispersed more efficiently in wind than were those of insect-pollinated species. Wind-pollinated species also exhibited a reduction in spectral contrast between showy subtending leaves and background foliage, reduced volatile emissions, and a greater degree of sexual dimorphism in color and scent. Uniovulate flowers and inflorescence condensation are conserved ancestral features in Leucadendron and likely served as exaptations in shifts to wind pollination. These results offer insights into the key modifications of male and female floral traits involved in transitions between insect and wind pollination.

Understanding the environmental and genetic mechanisms underlying locally adaptive trait variation across the ranges of species is a major focus of evolutionary biology. Combining transcriptome sequencing with common garden experiments on populations spanning geographical and environmental gradients holds promise for identifying such mechanisms. The South African shrub Protea repens displays diverse phenotypes in the wild along drought and temperature gradients. We grew plants from seeds collected at 19 populations spanning this species' range, and sequenced the transcriptomes of these plants to reveal gene pathways associated with adaptive trait variation. We related expression in co-expressed gene networks to trait phenotypes measured in the common garden and to source population climate. We found that expression in gene networks correlated with source-population environment and with plant traits. In particular, the activity of gene networks enriched for growth related pathways correlated strongly with source site minimum winter temperature and with leaf size, stem diameter and height in the garden. Other gene networks with enrichments for photosynthesis related genes showed associations with precipitation. Our results strongly suggest that this species displays population-level differences in gene expression that have been shaped by source population site climate, and that are reflected in trait variation along environmental gradients.

Banksia ericifolia is killed by fire and so depends upon seeds for persistence. In contrast, B. oblongifolia can persist after fire by resprouting from protected buds, as well as by recruiting seedlings. These serotinous species coexist in the fire-prone scrublands of the Sydney Basin. Here we report experiments that compared seed release from cones retained in the canopy, seed germination, and seedling establishment in these two species. B. oblongifolia seeds were released more quickly than B. ericifolia seeds after a fire, and B. oblongifolia follicles opened and shed seeds after exposure to lower temperatures than those of B. ericifolia. B. oblongifolia seeds germinated more quickly than those of B. ericifolia. The relative growth rates and leaf mass ratios (mean ratio of leaf dry mass to plant dry mass over sequential harvests) of the two species did not differ. Root : shoot ratios were significantly large and biomass allocation to roots was faster in B. oblongifolia seedlings. B. ericifolia seedlings survived low and intermediate levels of droughting better than B. oblongifolia under greenhouse conditions. In a field experiment in which water was not limiting, large B. oblongifolia seedlings had the highest survival rate. These results suggest that selection has acted on B. ericifolia to minimize the chance of zero seedling survival by distributing the risks over more than one germination episode. There was no consistent evidence to support the hypothesis that selection on this species has increased its probability of seedling survival during any one germination opportunity relative to its congener.

Oreocallis grandiflora (Lam.) R. Br. is an Ecuadorian species belonging to the Proteaceae family, commonly known as cucharillo (Loja and Zamora provinces), cucharilla (Sierra region), gañal (Bolívar province), and algil (Chimborazo province). Its leaves and flowers, collected during blooming, are traditionally used for oral administration to treat liver diseases, vaginal bleeding, and ovary/uterus inflammation and as digestive, diuretic, and hypoglycemic remedy. Related literature does not report any scientific evidences regarding the chemical composition of the used parts of this species (leaves and flowers), while few indications are reported about the healthy properties of their preparations. Based on these premises, the present research was performed with the objectives to fill the gaps of the chemical and biological knowledge about this species, enriching the knowledge related to the plant biodiversity of Amazonian Ecuador and to the ethnobotanical tradition of Andean communities. Chemical and biological investigation (in vitro antioxidant and anti-inflammatory activity) of flower and leaf hydroalcoholic extracts shed a light on the functional metabolites putatively involved in healthy properties of the O. grandiflora traditional preparations. The chemical fingerprinting achieved by HPTLC and 1HNMR analyses showed the presence of flavonoids, subsequently quantitatively estimated by AlCl3 complexation assay and HPLC-DAD. Silica gel chromatography allowed the isolation of the main compounds of the flower extract: quercetin 3-O-β-glucuronide and myricetin 3-O-β-glucuronide. RP-HPLC-DAD-MS analyses showed the presence of quercetin 3-O-rutinoside and isorhamnetin 3-O-rutinoside, in addition to the above-mentioned molecules, in the leaf extract. Regarding the antioxidant (DPPH test, a radical scavenging assay) and anti-inflammatory (WST-1 assay, an oxidative burst test) activities, leaf extract showed the most promising results when compared to the positive controls. The same extract, however, exhibited a higher cytotoxicity compared to the flower extract, indicating the latter preparation as the most interesting anti-inflammatory crude drug.

SUMMARY The response of seedlings of the sclerophyllous shrub, Protea repens (L.) L., to increasing concentrations of phosphorus (P), nitrogen (N) and a mixture of all essential nutrients excluding N and P (M) was determined in potted Clovelly soil collected from a lowland fynbos site at Pella, south-western Cape, South Africa. Pot culture resulted in increased soil mineral nitrogen, in particular nitrate, and decreased available (resin-extractable) phosphorus concentrations compared to field soil. High amounts of N (4-64 g m-2N) and M addition resulted in seedling mortality. Plant dry mass, leaf area and phosphorus and nitrogen contents increased in response to increasing application of P, but no significant differences were found in response to M. Increasing applications of N resulted in reduced plant dry mass, leaf area and phosphorus content. These patterns of mortality and growth are interpreted as a response to an imbalance between nitrogen and phosphorus availability. These results are compared to the response of mature fynbos shrubs to fertilizer additions in the field and the responses of potgrown sclerophyllous plants from other Mediterranean-type e,cosystems.

Euplassa cantareirae is a Neotropical Proteaceae, native to the Restinga forest in Brazil and it experiences a wide array of adverse environmental conditions, especially seasonal flooding and low nutrient availability. We aimed to investigate the effects of phosphorus (P) supply on plant growth and cluster root formation, as well as to characterize the main carboxylates released by the cluster roots of this species. We conducted a greenhouse experiment where seedlings were grown in a sandy soil and watered three times a week with nutrient solution with the following P concentrations: 0, 10, 50 or 100 μM. Cluster-root production per plant, tissue P concentrations, growth parameters and carboxylate release were recorded and analyzed. Remarkably, cluster-root formation, biomass production and leaf P concentration did not depend on P supply. These results differ from what have been found for almost all other investigated species, except for one other plant that inhabits a similar habitat in south-western Australia, Viminaria juncea (Fabaceae). The carboxylates that were found in the rhizosphere were similar to those reported before for other Proteaceae. Euplassa cantareirae is a Neotropical Proteaceae producing cluster roots, and contrary to what is known for other family members, it does not appear to regulate its cluster-root formation, growth and leaf P concentration by the soil P availability.

Rising temperatures associated with global climate change may alter the physiology and phenology of Protea species and cultivars. Protea species are assumed to be well adapted to warm summers characteristic of their natural Mediterranean-type habitat, but their plasticity in responding to higher growth temperatures is not known. Using infrared lamps, a greenhouse-based temperature gradient was constructed, with temperatures ranging from ambient to ambient + 3.1 °C. Potted plants of Protea ‘Pink Ice’ (P. compacta R. Br × P. susannae Phill.) were grown at five positions along this gradient for 12 months under irrigation. Simultaneously, a field verification experiment in a nearby commercial ‘Pink Ice’ orchard was conducted under ambient temperature and ambient + 2.9 °C. Increased sclerophylly (leaf dry weight per unit area) with increasing temperature indicated leaf structural changes. While leaf area based gas exchange (net CO2 assimilation rate, stomatal conductance and dark respiration rate) did not differ across the temperature gradient, leaf weight based CO2 assimilation rate and dark respiration rate decreased significantly towards the upper end of the temperature range. The optimum temperature for net CO2 assimilation rate (Topt) showed seasonal adjustments, but increased in response to experimental warming only in the field experiment. Significant temperature elevation resulted in an earlier onset of spring bud break, but warming extended inflorescence initiation from the spring flush to the summer flush, leading to delayed flowering. Aboveground biomass allocation shifted from inflorescences to leaves and to a lesser degree to stems, with elevated temperatures, whereas root growth was stimulated in the middle of the warming range. The results of this study suggest that elevated temperature may prolong the vegetative growth period in some Protea cultivars where water is not limiting, at the expense of flower production. This could have significant economic and marketing consequences for commercial cut flower production systems. The findings are also of significance to ecologists studying the responses of Proteaceae to climate change.

Plant species distributed across terrestrial islands can show significant genetic divergence among populations if seed and pollen dispersal are restricted. We assessed the genetic connectivity between populations of Grevillea georgeana, restricted to seven disjunct inselbergs in semi-arid Western Australia. The phylogeographical pattern and population genetics of populations were determined using sequence data from two plastid DNA intergenic spacers and ten nuclear microsatellite loci. The plastid DNA markers indicated high genetic differentiation among the majority of populations. Haplotypes were restricted to individual inselbergs, with the exception of two that were shared among three isolated populations that formed part of an elongated greenstone belt and that may be connected via inaccessible populations of G. georgeana. There was also strong differentiation within some of the populations, suggesting long-term isolation and persistence of G. georgeana on these terrestrial islands. Overall, the genetic patterns suggest limited seed dispersal, with differentiation in the plastid DNA genome being driven by genetic drift. In contrast, pollen movement, although generally restricted, may occur between neighbouring populations, resulting in a pattern of isolation by distance in the nuclear markers. This potential for limited or no seed dispersal, but connectivity via pollen flow, should be considered, given that many of the inselbergs are under consideration for resource development. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178, 155–168.

Protea mundii Klotsch (Proteaceae) has a disjunct distribution, with a large range in the Eastern Cape between Knysna and Port Elizabeth, and a smaller one in the Western Cape between Betty's Bay and Hermanus. Here, we provide population genetic and morphological evidence that populations in the two ranges belong to two distinct evolutionary lineages. Using 10 microsatellite loci, we show not only that the populations in the two ranges are genetically distinct but also that they may not even be sister to each other. We measured floral and leaf traits and determined that despite broad morphological similarities, the two lineages can be distinguished from each other by the width of their leaves (western — wider leaves, eastern — narrower leaves), the angle of the leaf bases (western — less acute, eastern — more acute), and the mass of their seeds. We conclude that these two lineages should be treated as independent entities for management and conservation purposes.

Because of the importance of reproduction in plant life history, the physiological costs of reproduction often influence vegetative structure and function. In dioecious species, these effects can be quite obvious, as different costs of male and female reproductive functions are entirely separated among different individuals in a population. In fire-prone ecosystems, in which recruitment is driven by fire frequency, many plants will maintain their seeds in the canopy, only to be released after a fire. The dioecious genus Leucadendron is a notable case of this, as females can maintain their seed cones for years, and, even more interestingly, species in the genus differ substantially in the degree to which males and females are sexually dimorphic. A recent study (Harris and Pannell 2010) argued that the hydraulic costs of maintaining seed cones for many years would effect the degree of sexual dimorphism among species. However, this assumed that shoot hydraulic architecture would be related to traits exhibiting sexual dimorphism. Here we explicitly test this hypothesis on two Leucadendron species. We found (1) that metrics of branch ramification used in the previous study to characterize dimorphism do not conform to known scaling relationships and (2) that sexual dimorphism in shoot architecture has no effect on hydraulic efficiency. Both of these results seriously question the pattern described by Harris and Pannell (2010) and suggest that the hydraulic costs of prolonged seed retention in Leucadendron do not significantly affect branch architecture.

Seed and seedling predation by small mammals, thought to be significant factors controlling the recruitment of Proteaceae in fynbos shrublands, were studied in a fynbos shrubland before and after a fire in March 1987. Seeds of Protea neriifolia R.Br. were planted inside and outside 14 mm mesh exclosures. The abundance of small mammals was recorded at two fynbos and five forest sites before the fire and at an additional forest and fynbos site after the fire. Seed predation reduced seedling recruitment from seeds planted in March 1986 in mature fynbos, but the reduction was significant only at the site with the highest abundance of small mammals. Seed predation did not significantly reduce seedling recruitment from seed planted in July, August and September 1986 in mature fynbos. The primary cause of seedling mortality before the fire was wilting, presumably owing to moisture stress. After the fire small mammal abundance decreased in burnt fynbos and increased in unburnt forest refuges until eight months after the fire when it increased again in the fynbos to a maximum of 41 animals per 100 trapnights two years after the fire. Seedling predation by small mammals had a limited impact after the fire probably because their numbers dropped soon after the fire. The effects of seed predation did not decrease with increasing distance from a forest refuge. Fungal pathogens and herbivory by insects were the primary causes of seedling mortality after the fire. Small mammal abundance in mature fynbos 25-30 years after a fire may have been too low to prevent the recruitment of a second cohort of P. neriifolia seedlings.

Six Hakea species varying greatly in seed size were selected for cotyledon damage experiments. The growth of seedlings with cotyledons partially or completely removed was monitored over 90 days. All seedlings perished by the fifth week when both cotyledons were removed irrespective of seed size. Partial removal of cotyledons caused a significant delay in the emergence of the first leaf, and reduction in root and shoot growth of the large-seeded species. The growth of seedlings of small-seeded species was less impacted by cotyledon damage. The rate of survival, root and shoot lengths and dry biomass of the seedlings were determined after 90 days. When seedlings were treated with balanced nutrient solutions following removal of the cotyledons, survival was 95–98%, but 0% when supplied with nutrient solutions lacking N or P or with water only. The addition of a balanced nutrient solution failed to restore complete growth of any species, but the rate of root elongation for the small-seeded species was maintained. Cotyledons provide nutrients to support early growth of Hakea seedlings, but other physiological roles for the cotyledons are also implicated. In conclusion, small-seeded Hakea species can tolerate cotyledons loss better than large-seeded species.

center dot Background and Aims The basal eudicot family Proteaceae (approx. 1700 species) shows considerable variation in floral symmetry but has received little attention in studies of evolutionary development at the genetic level. A framework for understanding the shifts in floral symmetry in Proteaceae is provided by reconstructing ancestral states on an upated phylogeny of the family, and homologues of CYCLOIDEA (CYC), a key gene for the control of floral symmetry in both monocots and eudicots, are characterized. center dot Methods Perianth symmetry transitions were reconstructed on a new species-level tree using parsimony and maximum likelihood. CYC-like genes in 35 species (31 genera) of Proteaceae were sequenced and their phylogeny was reconstructed. Shifts in selection pressure following gene duplication were investigated using nested branch-site models of sequence evolution. Expression patterns of CYC homologues were characterized in three species of Grevillea with different types of floral symmetry. center dot Key Results Zygomorphy has evolved 10-18 times independently in Proteaceae from actinomorphic ancestors, with at least four reversals to actinomorphy. A single duplication of CYC-like genes occurred prior to the diversification of Proteaceae, with putative loss or divergence of the ProtCYC1 paralogue in more than half of the species sampled. No shifts in selection pressure were detected in the branches subtending the two ProtCYC paralogues. However, the amino acid sequence preceding the TCP domain is strongly divergent in Grevillea ProtCYC1 compared with other species. ProtCYC genes were expressed in developing flowers of both actinomorphic and zygomorphic Grevillea species, with late asymmetric expression in the perianth of the latter. center dot Conclusion Proteaceae is a remarkable family in terms of the number of transitions in floral symmetry. Furthermore, although CYC-like genes in Grevillea have unusual sequence characteristics, they display patterns of expression that make them good candidates for playing a role in the establishment of floral symmetry.

Premise of research. Evolutionary transitions from insect to wind pollination are thought to have occurred many times during the angiosperm radiation. On the basis of floral features, several such transitions have been postulated for Leucadendron (Proteaceae), a dioecious genus of 96 taxa confined almost entirely to the Cape Floristic Region. To confirm whether these transitions took place, we carried out experimental tests for wind pollination and sampled insect flower visitors in 15 Leucadendron species, representing six clades in the genus.Methodology. In three clades in which an insect-wind shift has been inferred, we sampled species with traits suggestive of either wind or insect pollination. Plants were bagged with fine-mesh exclusion bags that excluded insects but allowed the passage of airborne pollen. Insects visiting female inflorescences were collected for identification and analysis of their pollen loads.Pivotal results. We found that insect exclusion had little effect on seed set of five spec...

Despite the diversity of branching architectures in plants, the impact of this morphological variation on hydraulic efficiency has been poorly studied. Branch junctions are commonly thought to be points of high hydraulic resistance, but adjustments in leaf area or xylem conduit abundance or dimensions could compensate for the additional hydraulic resistance of nodal junctions at the level of the entire shoot. Here we used the sexually dimorphic genus Leucadendron (Proteaceae) to test whether variation in branch ramification impacts shoot hydraulic efficiency. We found that branch ramification was related to leaf traits via Corner’s rules such that more highly ramified shoots had smaller leaves, but that branch ramification had little consistent impact on shoot hydraulic efficiency, whether measured on a leaf area or stem cross-sectional area basis. These results suggest that the presumed increase in resistance associated with branching nodes can be compensated by other adjustments at the shoot level (e.g. leaf area adjustments, increased ramification to add additional branches in parallel rather than in series) that maintain hydraulic efficiency at the level of the entire shoot. Despite large morphological differences between males and females in the genus Leucadendron, which are due to differences in pollination and reproduction between the sexes, the physiological differences between males and females are minimal.

Interspecific variation in plant hydraulic traits plays a major role in shaping species distributions across climates, yet variation within species is poorly understood. Here we report on intraspecific variation of hydraulic traits in Banksia serrata (L.f.) sampled from three sites characterised by contrasting climates (warm-wet, warm-dry and cool-wet). Hydraulic characteristics including vulnerability to embolism, hydraulic conductance, pressure-volume traits and key morphological traits were measured. Vulnerability to embolism in leaf and stem, defined by the water potential inducing 50 and 88% loss of hydraulic conductivity (P50 and P88 respectively), did not differ across sites. However, plants from the warm-dry environment exhibited higher stem conductivity (Ks) than the cool-wet environment. Leaf turgor loss point (TLP) did not vary among sites, but warm-dry site plants showed lower leaf capacitance (C*FT) and higher modulus of elasticity (ε) than the other two sites. Plants from the cool-wet site had lower specific leaf area (SLA) and plants from the warm-dry site had lower sapwood density (WD). Overall, key hydraulic traits were generally conserved across populations despite differences in mean site water availability, and the safety-efficiency trade-off was absent in this species. These results suggest that B. serrata has limited ability to adjust hydraulic architecture in response to environmental change and thus may be susceptible to climate change-type drought stress.