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SUMMARY: Leaves, as primary photosynthetic organs essential for high crop yield and quality, have attracted significant attention. The functions of DNA topoisomerase 1α (TOP1α) in various biological processes, including leaf development, in Brassica napus remain unknown. Here, four paralogs of BnaTOP1α, namely BnaA01.TOP1α, BnaA02.TOP1α, BnaC01.TOP1α and BnaC02.TOP1α, were identified and cloned in the B. napus inbred line 'K407'. Expression pattern analysis revealed that BnaA02.TOP1α and BnaC02.TOP1α, but not BnaA01.TOP1α and BnaC01.TOP1α, were persistently and highly expressed in B. napus true leaves. Preliminary analysis in Arabidopsis thaliana revealed that BnaA02.TOP1α and BnaC02.TOP1α paralogs, but not BnaA01.TOP1α and BnaC01.TOP1α, performed biological functions. Targeted mutations of four BnaTOP1α paralogs in B. napus using the CRISPR‐Cas9 system revealed that BnaA02.TOP1α and BnaC02.TOP1α served as functional paralogs and redundantly promoted true leaf number and size, thereby promoting true leaf biomass accumulation. Moreover, BnaA02.TOP1α modulated the levels of endogenous gibberellins, cytokinins and auxins by indirectly regulating several genes related to their metabolism processes. BnaA02.TOP1α directly activated BnaA03.CCS52A2 and BnaC09.AN3 by facilitating the recruitment of RNA polymerase II and modulating H3K27me3, H3K36me2 and H3K36me3 levels at these loci and indirectly activated the BnaA08.PARL1 expression, thereby positively controlling the true leaf size in B. napus. Additionally, BnaA02.TOP1α indirectly activated the BnaA07.PIN1 expression to positively regulate the true leaf number. These results reveal the important functions of BnaTOP1α and provide insights into the regulatory network controlling true leaf biomass accumulation in B. napus. Significance Statement: This study helps us understand the important functions of BnaTOP1α and provide insights into the regulatory network controlling true leaf biomass accumulation in B. napus. [ABSTRACT FROM AUTHOR]

Salinity is one of the main limiting factors driving the expansion of Spartina alterniflora by affecting plant functioning. Comparative studies of plant leaves, under 0 (T0), 5 (T5), 10 (T10), and 20 g/kg (T20) soil salinity, were carried out. Results showed that soil salinity significantly affected most leaf traits of S. alterniflora. Total and live leaf numbers first increased and then decreased with increasing soil salinity. Leaf morphology in T5 were substantially larger than another three treatments, and the ratio of leaf length to width considerably decreased with increasing soil salinity. As the soil salinity increased, leaf dry mass and leaf dry matter content (LDMC) displayed a pattern similar to total leaf number. Leaf mass traits indicated that while a more efficient nutrient conservation strategy was adopted in T10, S. alterniflora rapidly produced biomass in T0. Strong correlations were observed between leaf morphological and mass traits except for some parts of LDMC. The confidence ellipses of leaf traits indicated significant differences in leaf traits of the four treatments. We believe that insights into the aforementioned aspects can contribute to a better understanding of the responses of leaf traits of S. alterniflora and provide valuable information about its adaptation strategy. [ABSTRACT FROM AUTHOR]

The study of the effects of magnetic seed treatment (MST) has garnered significant attention from scientists due to its positive results in seed germination and seedling establishment. Few studies have comprehensively evaluated developmental parameters during the plant's vegetative stage. This study aimed to analyze tomato plants developed from magnetically treated seeds during the vegetative stage in terms of i) physiological responses, ii) growth dynamics, iii) correlation between physiological variables, and iv) the contribution of the technique compared with the performance of a highly commercial cultivar. There were 225 experimental units and three experimental groups with 75 plants each. Treatment one (T1) included plants developed from magnetically treated low-cost seeds; control 1 (C1) included plants developed from the same low-cost seeds without magnetic treatment (MT), and a secondary control (C2) was included with plants developed from high-cost seeds without MT to contrast the effect of MT on a low-cost seed with the performance of a high-cost one. Each plant was measured twice a week for leaf area, stem diameter, height, number of leaves, and chlorophyll content. A longitudinal study, using a repeated-measures design over time, was complemented by a correlational cross-sectional study through principal component analysis. A longitudinal study showed that magnetic treatment continuously modified the structure and biomass accumulation of plants throughout the vegetative stage. Plant height, stem diameter, and leaf number were directly and independently correlated with time, whereas chlorophyll content and leaf area were time-dependent. The effect of MST persists and improves the physiological responses of tomato plants up to the vegetative development stage. MST changes the growth dynamics of T1 compared to C1. Lastly, the physiological performance of plants generated from magnetically treated low-cost seeds was superior to that of plants generated from seeds without MST, and it closely followed the trend of the highly commercial cultivar, C2. To ensure the viability of MST as a biotechnological tool applicable to agriculture, future work should include the analysis of the subsequent phenological stages of the plants and determination of crop yield.

Abstract Ornamental foliage plants that have a dense appearance are highly valued. One way to achieve this is by using plant growth regulators as a tool for plant growth management. In a greenhouse with a mist irrigation system, a study was conducted on dwarf schefflera, an ornamental foliage plant, which was exposed to foliar application of gibberellic acid and benzyladenine hormones. The hormones were sprayed on dwarf schefflera leaves at 0, 100, and 200 mg/l concentrations, at 15-day intervals in three stages. The experiment was conducted as a factorial based on a completely randomized design, with four replicates. The combination of gibberellic acid and benzyladenine at 200 mg/l concentration had a significant effect on leaf number, leaf area, and plant height. The treatment also resulted in the highest content of photosynthetic pigments. Furthermore, the highest soluble carbohydrate to reducing sugars ratio was observed in treatments of 100 and 200 mg/l benzyladenine, and 200 mg/l gibberellic acid + benzyladenine. Stepwise regression analysis showed that root volume was the first variable to enter the model, explaining 44% of variations. The next variable was root fresh weight, and the two-variable model explained 63% of variations in leaf number. The greatest positive effect on leaf number was related to root fresh weight (0.43), which had a positive correlation with leaf number (0.47). The results showed that 200 mg/l concentration of gibberellic acid and benzyladenine significantly improved morphological growth, chlorophyll and carotenoid synthesis, and reducing sugar and soluble carbohydrate contents in dwarf schefflera.

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Main conclusion: A stable genetic transformation system for Erigeron breviscapus was developed. We cloned the EbYUC2 gene and genetically transformed it into Arabidopsis thaliana and E. breviscapus. The leaf number, YUC2 gene expression, and the endogenous auxin content in transgenic plants were significantly increased. Erigeron breviscapus is a prescription drug for the clinical treatment of cardiovascular and cerebrovascular diseases. The rosette leaves have the highest content of the major active compound scutellarin and are an important component in the yield of E. breviscapus. However, little is known about the genes related to the leaf number and flowering time of E. breviscapus. In our previous study, we identified three candidate genes related to the leaf number and flowering of E. breviscapus by combining resequencing data and genome-wide association study (GWAS). However, their specific functions remain to be characterized. In this study, we cloned and transformed the previously identified full-length EbYUC2 gene into Arabidopsis thaliana, developed the first stable genetic transformation system for E. breviscapus, and obtained the transgenic plants overexpressing EbYUC2. Compared with wild-type plants, the transgenic plants showed a significant increase in the number of leaves, which was correlated with the increased expression of EbYUC2. Consistently, the endogenous auxin content, particularly indole-3-acetic acid, in transgenic plants was also significantly increased. These results suggest that EbYUC2 may control the leaf number by regulating auxin biosynthesis, thereby laying a foundation for revealing the molecular mechanism governing the leaf number and flowering time of E. breviscapus. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of water stress and the application of potassium sulfate fertilizer on some growth characteristics of "Zahedi" date palm tissue culture-derived plants, this research was conducted as a factorial experiment based on a Randomized Complete Block Design with three replications on 45 plants. Water stress at three levels (Irrigation to the amount of 100, 80 and 60% of cumulative evaporation from Class A evaporation pan) and potassium sulfate fertilizer at five levels (zero, foliar application 2 g L-1 and 4 g L-1, soil application 50 g and 100 g for each plant) were applied to the plants. At the end of the experiment, the growth characteristics including trunk circumference, number of leaves, length and width of leaves, number of leaflets, length and width of leaflets, fresh and dry weight of aerial parts were measured and subjected to statistical analysis. The results showed that the increase in water stress had a significant negative effect on all vegetative growth traits, while the application of potassium sulfate moderated the effects of water stress. At the highest level of water stress (Irrigation to the amount of 60% of the water requirement) without application of potassium, the fresh and dry weight of aerial parts was recorded at 590 and 243 g respectively, but with the soil application of 100 g potassium sulfate at the same level of water stress, the fresh and dry weight of aerial parts increased significantly to 706 and 346, respectively. In this research, the soil application of potassium sulfate fertilizer had better effects on the growth characteristics of date palm plants than the foliar application method. In all levels of water stress, the application of potassium sulfate fertilizer, especially in soil application of 100 g for each plant, increased vegetative growth and fresh and dry weight of the date palm plant and improved its resistance to water stress.

Barley is a long-day plant with a major gene (PPD-H1) that determines its photoperiod sensitivity. Under long days (i.e. 16 h), flowering occurs earlier in sensitive (Ppd-H1) than in insensitive (ppd-H1) genotypes, while under short days (i.e. 12 h) both flower late and more or less simultaneously. We hypothesized that (i) the sensitive line should flower later than the insensitive line under very short days (<12 h), and (ii) both the sensitive and insensitive lines should have similar phenology under very long days (>18 h). When comparing a pair of spring isogenic lines for sensitive and insensitive PPD-H1 alleles (introgressing the PPD-H1 allele into the barley cultivar 'WI4441'), we found responses fully in line with expectations for the commonly explored range from 12 to 16–18 h. When the responses were extended to very short days, sensitivity increased noticeably, and time to flowering of the sensitive line was longer than that of the insensitive one. Under very long days, the sensitive line did not respond further (it seemed to have reached its minimum time to flowering under a 16 h period), while the insensitive line continued shortening its time to flowering until c. 21 h. Consequently, both lines flowered similarly under very long days, which opens opportunities to easily test for differences in earliness per se , as in wheat. [ABSTRACT FROM AUTHOR]

1. Introduction: Growth medium is an important and effective factor in the seedling production process. An appropriate growing medium should be available, relatively low cost and lightweight, resulting in higher use efficiently and better economical transportation. A healthy and strong seedling is necessary for better growth and development of mature plants in the field condition. According to reports, several factors including internal parameters and environmental agents have significant effects on seed germination and seedling growth. Light (intensity and quality), air humidity and substrate characteristics are considered as the most important environmental factors effective on seedling growth and development. Investigating the seed germination indices and seedling growth parameters under influence of type of substrate is crucial to produce seedlings with low cost and high quality. Physalis peruviana L. is an exotic fruit belonging to the Solanaceae family. The fruit is an enriched source of vitamins (C and A), iron, phosphorus and fiber. The fruit or its derivatives are used to produce certain products such as jellies, jams, juices and ice cream. The purpose of the current study was to investigate the possibility of replacement of common and high cost substrate components such as peat moss and coco peat with some other local and economical materials to produce low cost seedlings of Physalis peruviana with appropriate quality. 2. Materials and Methods: The current study was conducted based on completely randomized design with four replications in Mashhad city, Iran. The treatments included A (control): coco peat 60 % + peat moss 30 % + perlite 10 %, B: palm peat 60 % + peat moss 30 % + sand 10 %, C: palm peat 60 % + compost 30 % + sand 10 % and D: palm peat 60 % + vermicompost 30 % + sand 10 %. Physalis seeds was sown in the seedling tray. The number of germinated seeds was recorded every day to calculate germination indices including germination percentage and speed. Germination percentage was calculated by dividing the number of germinated seeds by the total number of sown seeds. At the end of 60th day, the fresh weight of stem and root was measured by digital scale (accuracy 0.001 g). The height of the aerial part and root length were measured with ruler. Leaf chlorophyll index was measured with chlorophyll meter (Model SPAD 502 Plus Chlorophyll Meter). Collar diameter and leaf area were measured by caliper (0.01 mm precision) and leaf area meter (Li-3100 cor), respectively. 3. Results and Discussion: The effect of substrate components on all measured traits such as seed germination percentage and speed, leaf number, leaf area, fresh and dry weight of stem and root, collar diameter, chlorophyll index, height of stem and root, electrolyte leakage and leaf relative water content was statistically significant at 5 % probability level. The results showed that the highest root fresh weight was related to seedlings grown on C substrate (2.3600 g) with no significant difference with D (2.2450 g) and B (2.2125 g) substrates. The highest value of fresh and dry weight of stem was related to control treatment (3.50 g and 0.350 g, respectively). Also, seedlings grown on C substrate had highest root dry weight (0.1525 g). The highest collar diameter was related to treatment D (3.0125 mm). The effect of studied treatments on leaf chlorophyll index was significant and the highest value (30.75 %) was recorded in seedlings grown on D substrate which was significantly higher than the control. The highest seed germination percentage was recorded in control (96.68 %) with no significant difference with substrates D (95.89 %) and B (93.61 %). Seeds sown in substrate C showed the lowest germination rate (82.68 %). The highest and lowest germination speed were recorded in substrate D (14.43 %) and substrate C (13.15 %), respectively. Based on recorded data, the highest electrolyte leakage was for seedlings grown on control substrate (28.985 %). The results showed that substrates B (9.50 cm2) and D (9.25 cm²) had the highest value of leaf area. According to studies conducted in different crops, the kind of substrate components could be effective on morphological, physiological and biochemical characteristics of plant. Generally, seed sowing in substrates with more water storage capacity, porosity and nutrients amount, and better texture and structure lead to better growth and development of root, subsequently resulting in stronger seedlings with higher qualitative characteristics. 4. Conclusion: The results of the current study indicated that the seedlings of P. Peruviana grown on alternative substrates had appropriate growth and proper characteristics (especially treatment D). Due to the easy availability of these compounds in the country, it seems that tested substrates could be used as a low-cost and favorable alternative for imported and expensive control substrate in P. Peruviana cultivation. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of water stress and the application of potassium sulfate fertilizer on some growth characteristics of "Zahedi" date palm tissue culture-derived plants, this research was conducted as a factorial experiment based on a Randomized Complete Block Design with three replications on 45 plants. Water stress at three levels (Irrigation to the amount of 100, 80 and 60% of cumulative evaporation from Class A evaporation pan) and potassium sulfate fertilizer at five levels (zero, foliar application 2 g L-1 and 4 g L-1, soil application 50 g and 100 g for each plant) were applied to the plants. At the end of the experiment, the growth characteristics including trunk circumference, number of leaves, length and width of leaves, number of leaflets, length and width of leaflets, fresh and dry weight of aerial parts were measured and subjected to statistical analysis. The results showed that the increase in water stress had a significant negative effect on all vegetative growth traits, while the application of potassium sulfate moderated the effects of water stress. At the highest level of water stress (Irrigation to the amount of 60% of the water requirement) without application of potassium, the fresh and dry weight of aerial parts was recorded at 590 and 243 g respectively, but with the soil application of 100 g potassium sulfate at the same level of water stress, the fresh and dry weight of aerial parts increased significantly to 706 and 346, respectively. In this research, the soil application of potassium sulfate fertilizer had better effects on the growth characteristics of date palm plants than the foliar application method. In all levels of water stress, the application of potassium sulfate fertilizer, especially in soil application of 100 g for each plant, increased vegetative growth and fresh and dry weight of the date palm plant and improved its resistance to water stress. [ABSTRACT FROM AUTHOR]

The effects of foliar application of potassium silicate and inoculation with mycorrhiza on alleviating the effects of drought stress on Matthiola incana plants were explored in a splitsplit-plot experiment based on a completely randomized design with three replications in Perndis Greenhouse Complex during 2019-2020. The main plot was assigned to drought stress at three levels (25%, 50%, and 70% FC), and the sub-plot was assigned to inoculation with arbuscular mycorrhizal fungi (AMF) at two levels (0 and 200 g of fungi per pot), and the sub-sub-plot was assigned to potassium silicate (PS) at three levels (0, 200, and 400 ppm). The results showed that at moderate drought stress (50% FC), stem dry weight was increased by about 20% compared to the control. The maximum root length (13.9 cm), which was about 53% higher than that of the control, was recorded in AMF-inoculated plants exposed to moderate drought stress and sprayed with 400 ppm SP. The results also showed that the foliar application of 400 ppm PS in the absence of AMF inoculation was related to 46% higher leaf dry weight than the treatments of 0 ppm SP with no AMF inoculation. The highest number of flowers in all drought stress levels was obtained from the application of the higher levels of PS. The maximum root dry weight was observed in AMF-inoculated plants exposed to moderate drought stress and treated with 400 ppm SP. Proline content was reduced by the application of 200 g of AMF and 400 ppm of PS at moderate and severe (25% FC) drought stress levels. In general, at moderate and severe drought stress levels, some vegetative and reproductive traits were improved by the foliar application of 400 ppm PS and AMF inoculation. [ABSTRACT FROM AUTHOR]

Let G be a simple, connected graph with minimum degree δ, radius r and leaf number L(G). We prove that We give similar bounds for triangle-free graphs. Infinite families of graphs are constructed to show that all the bounds here are sharp, except the one for r ≡ 1 modulo 3 in the above piecewise inequality. The results bring to literature new lower bounds on the leaf number and new upper bounds on the radius and connected domination number of a graph. Further, the techniques applied in this paper can be used to improve known asymptotically sharp bounds on the radius and diameter to sharp bounds. We consider simple graphs only. [ABSTRACT FROM AUTHOR]

Ornamental foliage plants have long been cultivated for their attractive leaves. Variation in leaf traits of ornamental foliage plants is one of the goals in breeding. MYB transcription factors regulate many aspects of leaf development, and thus influence morphological traits of leaves. However, little is known about the function of MYB transcription factors in leaf development of Cymbidium, one of the most economically important ornamental plants in the world. In the present study, a MYB transcription factor, CcMYB24, was identified and the corresponding gene cloned from a new orchid mutant, TRIR-2, which produces more leaves than control plants. The CcMYB24 showed a higher expression level in 'TRIR-2' than in control plants, and the protein was located in the nucleus. The sequence of CcMYB24 showed a high similarity with RAX2-like genes which belong to the R2R3-MYB gene family in other Cymbidium plants. Overexpression of CcMYB24 resulted in a phenotype with an increased number of leaves, elevated chlorophyll content, and decreased contents of carotenoids and flavonoids in Arabidopsis. These results provide functional evidence for the role of CcMYB24 in promoting the production of leaves in 'TRIR-2'. Understanding the role of CcMYB24 in Cymbidium will be beneficial for the molecular breeding of ornamental foliage plants. [ABSTRACT FROM AUTHOR]

Background and Aims Main shoot total leaf number (TLN) is a key determinant of plant leaf area and crop adaptation. Environmental factors other than photoperiod can affect TLN in sorghum, implying that leaf appearance rate (LAR) and development rate can differ in response to temperature. The objectives of this study were to determine (1) if temperature effects on TLN can be explained as a consequence of differences in temperature responses across phenological processes and (2) if genotypic differences in these responses can be linked to agroecological adaptation. Methods Nineteen sorghum genotypes were sown on 12 dates at two locations in Ethiopia with contrasting altitude, creating temperature differences independent of photoperiod. TLN and temperature were recorded in all experiments and LAR for six sowing dates. Key Results Eleven of the genotypes showed a temperature effect on TLN, which was associated with a significantly higher base temperature (T base) for LAR than for pre-anthesis development rate (DR). In contrast, genotypes with no effect of temperature on TLN had similar T base for LAR and DR. Across genotypes, T base for LAR and DR were highly correlated, but genotypes with low T base had the greatest difference in T base between the two processes. Genotypic differences were associated with racial grouping. Conclusions Genotypic and racial differences in responses of phenological processes to temperature, in particular in T base, can affect specific adaptation to agroecological zones, as these differences can affect TLN in response to temperature and hence canopy size and the duration of the pre-anthesis period. These can both affect the amount of water used and radiation intercepted pre-anthesis. A multi-disciplinary approach is required to identify genotype × environment × management combinations that can best capture the ensuing specific adaptation. [ABSTRACT FROM AUTHOR]

Quantifying the effects of various environmental conditions on maize leaf number is essential to understanding the environmental adaptations and population structure of maize plants and for enhancing maize productivity. In this study, seeds of three temperate-adapted maize cultivars, each belonging to different maturity classes, were sown on eight different dates. Sowing dates ranged from the middle of April to early July, which allowed us to cover a wide range of environmental conditions. Random forest regression and multiple regression models with variance partitioning analyses were used to assess the effects of environmental factors on the number of leaves and their distributions on maize primary stems. We demonstrated that the total leaf number (TLN) increased in the three cultivars in the following order: FK139 < JNK728 < ZD958, and variations in TLN for each cultivar were 1.5, 1.76, and 2.75 leaves, respectively. The variation in TLN was ascribed to changes in LB (leaf number below the primary ear), which were higher than variations in LA (leaf number above the primary ear). Variations in TLN and LB were mainly affected by the photoperiod during growth stages V7 to V11, and differences in TLN and LB in response to different photoperiods ranged from 1.34 to 2.95 leaves h-l. Variations in LA was mainly affected by temperature-related factors. Therefore, the results of this study enhanced our current understanding of key environmental conditions that affect maize leaf numbers, and provides scientific support for the benefits of adjusting sowing dates and selecting suitable cultivars to mitigate the effects of climate change on maize production. [ABSTRACT FROM AUTHOR]

Rice leaf is a solar panel of photosynthesis and determines the light energy utilization and yield of plants. Leaf numbers appear as S-type or parabola-type growth curves throughout their development. However, the ways in which the genes regulate the process of leaf numbers still remain poorly understood. This paper first identified five QTLs associated with leaf numbers using single-segment substitution lines (SSSLs). Then, the epistatic effects between double QTLs were estimated via the decomposition of the QTL polymerization effects. Additionally, further the expression patterns and functions for these five QTLs and their epistasis were revealed by the methodologies of conditional QTL mapping and functional QTL mapping, respectively. The five SSSLs were detected as having significant additive and/or dominant effects at one or more stages, all of which increased the leaf numbers, except for the negative additive effect of the first SSSL. Seven pairs of QTLs interacted each other via three or four epistatic components, with the opposite effects in the case of single genes, i.e., most epistatic effects were negative. The five QTLs expressed their effects mainly in three stages, namely within 14 days, from 28 days to 42 days, and from 49 days to 63 days after transplantation. Positive effects and negative interactions of the QTLs were observed in the early and the late stages, but opposite interactions were observed in the middle stage. Mainly, three functional parameters, including the inflexion point, the peak value, and the degradation rate, were regulated via the QTL effects and their opposite interactions. This paper uncovered the genetic rule of five QTLs on the leaf numbers, including the interaction, expression, and function features. The information will be helpful to understand the genetic mechanism for developmental traits. [ABSTRACT FROM AUTHOR]

The study of the effects of magnetic seed treatment (MST) has garnered significant attention from scientists due to its positive results in seed germination and seedling establishment. Few studies have comprehensively evaluated developmental parameters during the plant's vegetative stage. This study aimed to analyze tomato plants developed from magnetically treated seeds during the vegetative stage in terms of i) physiological responses, ii) growth dynamics, iii) correlation between physiological variables, and iv) the contribution of the technique compared with the performance of a highly commercial cultivar. There were 225 experimental units and three experimental groups with 75 plants each. Treatment one (T 1 ) included plants developed from magnetically treated low-cost seeds; control 1 (C 1 ) included plants developed from the same low-cost seeds without magnetic treatment (MT), and a secondary control (C 2 ) was included with plants developed from high-cost seeds without MT to contrast the effect of MT on a low-cost seed with the performance of a high-cost one. Each plant was measured twice a week for leaf area, stem diameter, height, number of leaves, and chlorophyll content. A longitudinal study, using a repeated-measures design over time, was complemented by a correlational cross-sectional study through principal component analysis. A longitudinal study showed that magnetic treatment continuously modified the structure and biomass accumulation of plants throughout the vegetative stage. Plant height, stem diameter, and leaf number were directly and independently correlated with time, whereas chlorophyll content and leaf area were time-dependent. The effect of MST persists and improves the physiological responses of tomato plants up to the vegetative development stage. MST changes the growth dynamics of T 1 compared to C 1 . Lastly, the physiological performance of plants generated from magnetically treated low-cost seeds was superior to that of plants generated from seeds without MST, and it closely followed the trend of the highly commercial cultivar, C 2 . To ensure the viability of MST as a biotechnological tool applicable to agriculture, future work should include the analysis of the subsequent phenological stages of the plants and determination of crop yield., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Javier Torres-Osorio reports financial support was provided by Colombia Ministry of Science Technology and Innovation. Javier Torres-Osorio reports financial support was provided by COLFOG MIP S.A.S. Javier Torres-Osorio reports a relationship with University of Caldas that includes: employment. Carolina Zamorano-Montanez reports a relationship with University of Caldas that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Salt stress (SS) refers to excessive soluble salt concentrations in the plant root zone. SS also causes cellular water deficits, ion toxicity, and oxidative stress in plants, all of which can cause growth inhibition, molecular damage, and even plant mortality. Lettuce (Lactuca sativa L.) has a threshold electrical conductivity of 1.3–2.0 dS/m. Thus, this research focused on physiological, morphological, and biochemical attributes in multiple lettuce genotypes under SS compared to plants grown under control conditions. The experiment was arranged in a randomized complete block design with four replications. One month after planting, the salt treatment was applied at the rate of 100 millimoles (mM). The 0 mM salt in water treatment was considered the control. A significant effect of SS on different morphological and physiological traits was observed in one-month-old lettuce plants. PI 212099, Buttercrunch-1, and PI 171676 were highly salt-tolerant. Genotypes with high salt tolerance usually had poor growth potential under control conditions. This suggests that the morphological and physiological response of 38 lettuce cultivars towards SS is genotype dependent. Identifying SS’s physiological, morphological, and biochemical attributes in lettuce may help plant-breeders develop salt-tolerant lettuce genotypes.

Onion is a biennial plant that produces a bulb. The larger the onion bulb, the more valuable it becomes. Therefore, it is important to study bulb weight and plant size components affecting it. For this study, four New Mexico State Univ. breeding lines and two commercial cultivars, 'Rumba' and 'Stockton Early Yellow', were selected. These breeding lines and cultivars were evaluated for plant height, leaf number and sheath diameter, at five different dates two weeks apart throughout the growing season, and for bulb weight upon harvest. The experiment was designed as a randomized complete block design with three blocks each containing four replications. Plant size components were all positively correlated with each other and with bulb weight with correlation coefficients above 0.50. NMSU breeding lines also exhibited greater average bulb weights than commercial cultivars. Sheath diameter proved to be the best predictor of bulb size, showing strong positive correlations with bulb weight at around 12 weeks after transplanting, and positive correlations are observed as early as 6–8 weeks after transplanting. [ABSTRACT FROM AUTHOR]

Grevillea robusta is recognized by the pinnate and deeply lobed fernlike leaves, dark green adaxial, silky with whitish, by showy yellowish flowers clustered on and by black curved pod. Techniques of seed dormancy avoidance were written for different species by different authors. However, a combined effect of watering frequency and germination percentage for successful germination of G. robusta seed is scantly documented. Therefore, this study was conducted with the aim of evaluating the effect of mulching and watering frequency on seed germination, height and leaf number. The research design was factorial experiment in the arrangement of eight different treatments with three replications. The plot size was 1m by 1m and the spacing between plot and block were 0.4m and 1m respectively. The frequency of watering (w) and mulching (M) percentage results variation in height and germination percentage. M0% with watering in one day gap (w1), M0% with watering all day (wa), mulching above 75% and no mulching generally delay total germination percentages of seedling. The optimum mulching (%) and frequency of water for rate of normal seed germination was between mulching M25% wa to M50% wa. The optimum mulching and frequency of water for seedling height was attended at M50% wa. Therefore, the germination responses of seed of G. robusta vary as per mulching percentage and watering frequency it has. Further study on how mulching and watering frequency improve the soil microbial activity and temperature during seed germination of G. robusta species on the seedbed across Agroecology is needed.

A petri dish experiment and pot experiment were conducted to investigate the effect of seed soaking on the germination of Pea and Okra and the early growth of Okra. There were four soaking times, 0h, 5h, 10h, and 24h. The results showed positive effects of seed soaking on the emergence and growth of the two crops. Results showed that the germination percentage did not correlate linearly with the increase in Pea seed soaking time, while in Okra, the germination percentage increased with the increase in soaking time. Both crops had the highest germination percentage at 24h soaking time which was 96% for Pea, and 76% for Okra. Pea seeds soaked for 24h had the longest radicle followed by the control treatment (0h). For Okra, there was a steady increase in the radicle and plumule length along with the increase in soaking period. For Okra, the height of the plant in the fourth week in the treatment of soaking for 24 hours was about twice the height of the plant in the same week in the treatment of the control. These results could be used in improving the growth of the crops.

Rice leaf is a solar panel of photosynthesis and determines the light energy utilization and yield of plants. Leaf numbers appear as S-type or parabola-type growth curves throughout their development. However, the ways in which the genes regulate the process of leaf numbers still remain poorly understood. This paper first identified five QTLs associated with leaf numbers using single-segment substitution lines (SSSLs). Then, the epistatic effects between double QTLs were estimated via the decomposition of the QTL polymerization effects. Additionally, further the expression patterns and functions for these five QTLs and their epistasis were revealed by the methodologies of conditional QTL mapping and functional QTL mapping, respectively. The five SSSLs were detected as having significant additive and/or dominant effects at one or more stages, all of which increased the leaf numbers, except for the negative additive effect of the first SSSL. Seven pairs of QTLs interacted each other via three or four epistatic components, with the opposite effects in the case of single genes, i.e., most epistatic effects were negative. The five QTLs expressed their effects mainly in three stages, namely within 14 days, from 28 days to 42 days, and from 49 days to 63 days after transplantation. Positive effects and negative interactions of the QTLs were observed in the early and the late stages, but opposite interactions were observed in the middle stage. Mainly, three functional parameters, including the inflexion point, the peak value, and the degradation rate, were regulated via the QTL effects and their opposite interactions. This paper uncovered the genetic rule of five QTLs on the leaf numbers, including the interaction, expression, and function features. The information will be helpful to understand the genetic mechanism for developmental traits.

Here, we prove new asymptotically sharp lower bounds on the leaf number in graphs of girth at least 4 or 5. The results imply upper bounds on the diameter of the aforementioned classes of graphs. In addition, we apply the dead leaves method to produce a short, unified, alternate proof to one of the results by Bonsma. We consider simple graphs only unless otherwise specified. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of compensatory behavior of planting density, corm weight and planting depth on vegetative characteristics and yield of saffron stigma (Crocus sativus L.), a factorial split plot experiment based on randomized complete block design with three replications was conducted in the Khorasan Razavi Agriculture and natural resources Research and education Center (Gonabad Research Station) during the three cropping years 2018-2020. In this study, planting density treatment (four levels of 60, 90, 120 and 150 corms per square meter) was considered as the main plots and factorial of planting depth (two levels of 15±2 and 25±2 cm from the soil surface) and corm weight (two Levels 4± 1 and 8 ± 1 gr) were considered as the subplots. The results showed that density increasing caused a significant increase in yield (p <0.05) and the other studied traits. On the based of these, increasing density from 60 to 150 corms per square meter increased the number of flowers and stigma dry weight by 174 and 192 percent in the first year, 100 and 109 percent in the second year, 128 and 129 percent in the third year, respectively. The results also showed that increasing corm weight from 4 to 8 g increased flower number and stigma dry weight by 133 and 138% in the first year, 14 and 15% in the second year respectively, but decreased by 10 and 10% in the third year. Based on the results of this study, increasing the planting depth from 15 to 25 cm reduced the stigma yield and other traits of saffron. The effect of dual and triple interactions on the studied traits was mainly significant. Overall, the results showed that the use of larger mother corms has a higher priority only in the early years and its importance decreases with increasing farm age. It seems that in a different strategy, more profit can be achieved by planting less corm weight (i.e.lower costs) and its effect compensation via a combination of less depth and especially more density (i.e. higher yield and income). [ABSTRACT FROM AUTHOR]

• Biostimulating effects of Nostoc piscinale on maize were investigated in field trials. • N. piscinale suspensions stimulated earlier development of leaves. • Treatments also delayed chlorophyll degradation in the reproductive stages. • These beneficial effects increased grain yield and grain protein content. Biostimulants, when applied to plants in small amounts, increase crop yield and plant tolerance to abiotic and biotic stress. They play an important role in the development of new environmentally sustainable technologies. The aim of the current experiment was to investigate the potential of a cyanobacterium strain (Nostoc piscinale) to improve the growth, grain yield and stress tolerance of maize (Zea mays SY Zephir hybrid). Field trials were established at two sites. Freeze-dried biomass of N. piscinale resuspended in tap water (1g/L DW) was applied as a single foliar treatment (400 L/ha) at the V6-V7 phenological stage. Number of leaves, chlorophyll content, relative water content (RWC%) and free proline content were measured weekly. Grain yield, yield components and grain protein content were measured at harvest. N. piscinale treated maize had significantly earlier development in the vegetative growth stages with a higher number of leaves. Chlorophyll content (SPAD value) was significantly higher in the treated plants during the reproductive stages. There was little difference in the RWC and proline content compared to control plants. Faster vegetative growth and higher chlorophyll content in the cyanobacterium treated plants meant great photosynthetic light absorption over a longer period of time, resulting in significantly higher grain yield (6.5% and 11.5% at the two production sites) and increased grain protein content. Grain yield was significantly influenced by cob length and thousand grain weight. In conclusion, it was proved in field trials conducted in two different regions in Hungary that a single foliar application of a cyanobacterium-based biostimulant can contribute to crop production in a sustainable and environmentally friendly manner. [ABSTRACT FROM AUTHOR]

Candidatus Liberibacter asiaticus' (CLas) is the predominant causal agent of citrus huanglongbing, the most devastating citrus disease worldwide. CLas colonizes phloem tissue and causes phloem dysfunction. The pathogen population size in local tissues and in the whole plant is critical for the development of disease symptoms by determining the load of pathogenicity factors and metabolic burden to the host. However, the total population size of CLas in a whole plant and the ratio of CLas to citrus cells in local tissues have not been addressed previously. The total CLas population size for 2.5-year-old 'Valencia' sweet orange on 'Kuharske' citrange rootstock trees was quantified using quantitative PCR to be approximately 1.74 × 109 cells/tree, whereas 7- and 20-year-old sweet orange trees were estimated to be 4.3 × 1010 cells/tree, and 6.0 × 1010 cells/tree, respectively. The majority of CLas cells were distributed in leaf tissues (55.58%), followed by those in branch (36.78%), feeder root (4.75%), trunk (2.39%), and structural root (0.51%) tissues. The ratios of citrus cells to CLas cells for branch, leaf, trunk, feeder root, and structural root samples were within approximately 39 to 79, 44 to 124, 153 to 1,355, 191 to 1,054, and 561 to 3,760, respectively, representing the metabolic burden of CLas in different organs. It was estimated that the ratios of phloem cells to CLas cells for branch, leaf, trunk, feeder root, and structural root samples are approximately 0.39 to 0.79, 0.44 to 1.24, 1.53 to 13.55, 1.91 to 10.54, and 5.61 to 37.60, respectively. Approximately 0.01% of the total citrus phloem volume was estimated to be occupied by CLas, explaining the difficulty to observe CLas in most tissues under transmission electron microscopy. The CLas titer inside the leaf was estimated to be approximately 1.64 × 106 cells/leaf or 9.2 × 104 cells cm-2 in leaves, approximately 104 times less than that of typical apoplastic bacterial pathogens. This study provides quantitative estimates of phloem colonization by bacterial pathogens and furthers the understanding of the biology and virulence mechanisms of CLas. [ABSTRACT FROM AUTHOR]

Onion is a biennial plant that produces a bulb. The larger the onion bulb, the more valuable it becomes. Therefore, it is important to study bulb weight and plant size components affecting it. For this study, four New Mexico State Univ. breeding lines and two commercial cultivars, ‘Rumba’ and ‘Stockton Early Yellow’, were selected. These breeding lines and cultivars were evaluated for plant height, leaf number and sheath diameter, at five different dates two weeks apart throughout the growing season, and for bulb weight upon harvest. The experiment was designed as a randomized complete block design with three blocks each containing four replications. Plant size components were all positively correlated with each other and with bulb weight with correlation coefficients above 0.50. NMSU breeding lines also exhibited greater average bulb weights than commercial cultivars. Sheath diameter proved to be the best predictor of bulb size, showing strong positive correlations with bulb weight at around 12 weeks after transplanting, and positive correlations are observed as early as 6–8 weeks after transplanting.

The purple passion fruit (Passiflora edulis Sims f. edulis) is a promising crop in Colombia because of its high potential for international markets and high profitability. However, without adequate fertilization, the metabolic processes of plant growth can be affected. The objective of this research was to evaluate the effect of macro- and micronutrient deficiencies on growth, photosynthesis, and transpiration in purple passion fruit plants during vegetative development. Seedlings with four to six leaves (three-months-old) were transplanted to a sand culture and subjected to mineral deficiencies using the missing element technique under greenhouse conditions. The plants subjected to Fe deficiency had the lowest maximum photosynthetic rate at saturation by light (1.72 µmol CO2 m−2s−1) at 72 days after treatment, while the lowest apparent quantum efficiency (0.008 µmol CO2 µmol photons−1) was observed in the plants with Mg deficiency. The lowest values of maximum photochemical efficiency of photosystem II, Fv/Fm (0.69) and transpiration rate (2.39 µg H2O cm−2s−1) were found in the plants with P deficiency. The mineral nutrient deficiencies negatively affected metabolic processes in the purple passion fruit plants, with the highest impact on photosynthesis observed with the Fe or Mg deficiencies. The plants subjected to P deficiencies were the most affected plants in terms of transpiration rate. [ABSTRACT FROM AUTHOR]

Introduction: The fresh, steamed and boiled spinach were used because of antioxidant compounds that have great biological value. This plant is usually rich in nitrates that can play an important role in reducing heart attacks. Each year, more than 30% of the area under cultivation leafy vegetables in Iran, was allocated to spinach. Spinach growing in both spring and autumn or summer, has poor quality due to stem production. Higher spinach yield have been reported in autumn cultivation (compared to spring or winter planting). The nitrogen-rich lands, little light condition, excessive use of nitrogenous fertilizers and plants during the growing season short cause some plants like spinach, are faced with the problem of nitrate accumulation. The accumulation of nitrate in vegetables will be different depending on the species and genetic differences. Materials and Methods: This research was conducted for two years in Kabootarabad Agricultural Research Station of Isfahan in order to determine the most suitable planting prickly seed spinach. Each year, of experiment was based on randomized complete block design with four replications and the results were reported based on two-year combined data analysis. Five planting dates at intervals of 15 days from the beginning of September had been adjusted. Prickly seed spinach was prepared from Seed and Plant Improvement Institute. In full leaf development stage and before the harvest of each plot, 10 plants randomly were selected and measured attributes including number of leaves, leaf length, leaf width and length of the petiole. In order to assess yield, two central rows of plants per plot (surface equivalent to two square meters) were analyzed after removing two distance of half a meter from each side. Nitrate samples were analyzed using ion analyzer. Statistical analyses of the data, correlated traits were performed using SAS software and comparisons of means using LSD at 5%. Result and discussion: According to the results, year had no significant effect on traits. 5 September sowing date, GDD=571 was diagnosed as the best spinach planting date yielding 43 tons per hectare. Delayed planting date of 5 September to 22 October showed significant yield reduction and the amount of nitrate accumulation in plants also increased linearly. Number of leaves can be changed as one of the main factors influencing the performance of spinach according to cultivar and environmental conditions and in some studies they were ranged from 12 to 23. Amounts of nitrate accumulation in spinach were 2675, 2898, 3189 and 3571 ppm of fresh weight in different planting date of 5 September (571 GDD), 22 September (354 GDD), 6 October (193 GDD) and 22 October (84 GDD), respectively. The different sowing date, petiole nitrate accumulation varied from 3513 to 4680 ppm. Nitrate accumulation was ranged from 2135 to 3125 ppm wet weight in leaf blade. Different planting dates can influence on the length of day and intensity of light and thus can affect the amount of nitrate in plant. After planting date of August 22, temperature and radiation also reduced, and therefore it is natural that reduce the activity of the enzyme nitrate reductase and be more prepared conditions for nitrate accumulation. According to the World Health Organization, the uptake of nitrate and nitrite per kg of body weight daily allowance, equal to 0.06 and 0- 7.3 mg has been reported. The quality of light received by the plant also had an effect on nitrate accumulation, and red light compared to blue light has a greater role in stimulating the enzyme nitrate reductase activity and thus is more effective in reducing nitrate accumulation. Conclusion: Climatic conditions affect the quantity and quality of vegetative organs. The results of this study showed that unsuitable spinach planting date will reduce not only yield, but also increases the concentration of nitrate (over 2500 ppm of fresh weight) and it may causes risks for consumers.

Let G be a simple, connected, triangle-free graph with minimum degree δ and leaf number L(G). We prove that if L(G) ≤2δ − 1, then G is either Hamiltonian or G ∈ ℱ2, where ℱ2 is the class of non-Hamiltonian graphs with leaf number 2δ − 1. Further, if L(G) ≤ 2δ, we show that G is traceable or G ∈ ℱ3. The results, apart from strengthening theorems in [17, 16] for this class of graphs, provide a sufficient condition for a triangle-free graph to be Hamiltonian or traceable based on leaf number and minimum degree. [ABSTRACT FROM AUTHOR]

Introduction: With 12 million tons production per year, garlic is the fourth important crop in world. In addition to its medical value, it has been used in food industry. The Hamedan province with 1900 ha cultivation area and 38 percent of production is one of the most important garlic area productions in Iran. Few studies on water use and management of garlic exist in the world. Garlic is very sensitive to water deficit especially in tubers initiation and ripening periods. The current research was done because of scarce research on garlic production under water deficit condition in Iran and importance of plant nutrition and nutrients especially nitrogen on garlic production under stressful conditions. Nitrogen is necessary and important element for increasing the yield and quality of garlic. Application of nitrogen increases the growth trend of garlic such as number of leaves, leaf length and plant body. Reports have shown that garlic has high nitrogen requirement, particularly in the early stages of growth. Materials and Methods: This study was conducted for evaluating the combined effects of nitrogen and irrigation on the yield and quality of garlic (Allium sativumL.). The study was performed as a split-block based on randomized complete blocks design with factors of irrigation at four levels (0-3(normal irrigation), 3-6 (slight water deficit), 6-9 (moderate water deficit) and 9-12 (sever water deficit) meters distance from main line source sprinkler system), nitrogen at four levels (0, 50,100 and 150 kg nitrogen per ha) using three replications and line source sprinkler irrigation system. The total water of irrigation levels was measured by boxes that were fixed in meddle of each plot. The statistical analysis of results were performed using themethod described by Hanks (1980). The chlorophyll index was measured using the chlorophyll meter 502 (Minolta, Spain). The chlorophyll a and bwas measured by the method described by Arnon (1946) and Gross (1991) in fresh leaf samples using spectrophotometer at 645 and 663 nm. Data were subjected to analysis of variance using MSTATC and SPSS softwares. Duncan’s multiple range test at p≤0.05 probability level was applied to compare the mean values of measured attributes. The Excel software (Excel software 2007, Microsoft Inc., WA, USA) was used to draw Figures. Results and Discussion: The results showed that, the application of nitrogen significantly affected most of measured attributes. The application of 150 kg N per ha showed highest stem height (40.5 cm), dry weight of stem (5.34 g),wet weight of stem (69.5 g), chlorophyll index (49.7),chlorophyll a (9.8 mg.g-1dw) and chlorophyll b (4.04 mg.g-1dw) and increased stem height, dry and wet weight of stem, chlorophyll index and chlorophyll a and b around 7, 6, 7, 12, 22 and 36 percent, respectively. The irrigation levels significantly affected most of measured attributes similar to the nitrogen levels. The application of 409 mm irrigation water per growing season resulted to maximum stem height (41.9 cm), leaf number (7.5), dry weight of stem (5.39 g) and wet weight of stem (70.1 g), chlorophyll index (50.5) and chlorophyll a (10.2 mg.g-1dw) and chlorophyll b (4.04 mg.g-1dw). The severe water deficit (application of 138 mm irrigation water per growing season) decreased stem height, leaf numbers, dry and wet weight of stem, chlorophyll index and chlorophyll a and b about 13, 36, 12, 12, 19, 42 and 44 percent, respectively. The two way interaction of nitrogen and irrigation was significant and mostly synergistic on wet and dry weight of stem. The highest amounts of stem wet weight (73.2 g) and stem dry weight (5.63 g) were resulted from application of 150 kg nitrogen per ha under full irrigated condition that increased dry and wet weight of stem 17 and 25 percent respectively comparing with without nitrogen application under sever water deficit condition. Application of 409 mm irrigation and 100 kg N per ha is suitable for condition that enough irrigation waterexists. However in water deficit condition, the application of 150 kg nitrogen per ha could be recommended. Conclusion: In general, to achieve the optimum growth of garlic in similar soils and climatic conditions, application of 100 kg nitrogen per ha would be recommended under normal irrigation conditions while at water deficit conditions the application150 kg nitrogen per ha could be recommended that had only two percent difference with the mentioned treatment and this difference was not significant.

Alfalfa (Medicago sativa L.) plant growth decreases when cultivated under salinity or irrigated with salty water. Inoculation with plant growth-promoting bacteria (PGPB) is a method for mitigating the harmful effects of salinity on plants growth. To investigate salt-tolerant PGPB with salt-tolerant and salt-sensitive alfalfa cultivar interactions under salinity, some physiological and agronomical aspects were investigated. The inoculated plants of alfalfa cultivars with Hartmannibacter. diazotrophicus and Pseudomonas sp. bacteria were compared with non-inoculated plants. Plants were grown in growth room and irrigated with tap water until 6–7 weeks, and then, salinity stress imposed by irrigating with tap water (control), 10 dS m−1 and 20 dS m−1 NaCl. Salinity reduced relative water content (RWC), membrane stability index (MSI), K+, photosynthesis rate (Pn) and stomatal conductance (gs), leaf number, height, and dry weight, and increased sodium in all cultivars. Inoculation of cultivars with both PGPB mitigated the negative effects of salinity on plants growth by increasing the root length and weight, nodule number, chlorophyll pigments, RWC, MSI, Pn, and gs. Chlorophyll pigments, plant height and leaf number, Na+, K+/Na+, and nodule number improved more pronounced through inoculating with Pseudomonas sp., whereas K+, carotenoids, and RWC improved more pronounced through H. diazotrophicus under salinity. The results showed inoculation with two bacteria improved growth performance in salt-tolerant and salt-sensitive cultivars under 10 dS m−1, but at high salinity (20 dS m−1), inoculation was successful only in salt-tolerant alfalfa cultivars. [ABSTRACT FROM AUTHOR]

[Objective] Aiming at the problem of low sugar content in early-ripening citrus fruits in Yunnan province, we studied the effect of number of leaves on bearing branch on fruit hypertrophy and quality of early maturing citrus. [Method] Five early maturing citrus varieties’ Okitus wase’with the same age and similar growth were selected as the test materials, according to the number of different leaves on the bearing branch, we measured transverse diameter, vertical diameter and stalk coarseness of the fruit, determined the contents of soluble sugar (glucose, sucrose, fructose) , soluble solids and titratable acid. [Result] The results showed that the difference of the number of leaves on bearing branch had a significant effect on the fruit stalk coarseness and fruit hypertrophy.From late May to late September, the fruit transverse diameter, vertical diameter of 7 leaves on the bearing branch was significantly higher than that of bearing branch with 1 or 4 leaves;and from mid-May to late September, the fruit stalk coarseness of bearing branch with 7 leaves was significantly higher than that of bearing branch with 1 leaf;the glucose, fructose, single weight, peel weight and titratable acid content of the fruit with 7 leaves on bearing branch were significantly higher than the fruit with 1 leaf;the b value of fruit with 4 leaves on bearing branch was significantly higher than that with7 leaves. [Conclusion] Early maturing citrus’ Okitus wase’with the 7 leaves on bearing branch had a significant effect on fruit hypertrophy and quality.In the process of practical production management, We could stimulate the bearing branch with many leaves, select the best ratio of leaf to fruit, reduce the leafless and less leafless bearing branch, and improve the cultivation management technique and the quality of early maturing citrus’ Okitus wase’in Yunnan Province. [ABSTRACT FROM AUTHOR]

This experiment was conducted to evaluate the effect of four types of nutrient solutions on growth, quantitative and qualitative characteristics of Lilium cut flower (Lilium LA Hybrid Fangio) in soilless culture in a completely randomized design with four treatments, four replications with 10 pots per replicate in the research greenhouse of the University of Guilan. Plants with four treatments of macro elements (S1, S2, S3 and S4 highest to lowest macro elements, respectivly) were arranged on the base of modified Quick nutrient solution with different salts including potassium nitrate, di potassium hydrogen phosphate, potassium dihydrogen phosphate, calcium nitrate, ammonium nitrate, calcium chloride and Magnesium sulfate mg/L. All macro elements contained similar amounts of micro-elements. Results showed that there were significant difference between different treatments of macro elements for length of bud, leaf length and width, number of leaves, daughter bulb weight, total chlorophyll content of leaf, anthocyanin and petal protein, leaf nitrogen, potassium, phosphorus and magnesium. Also, significant difference was not observed for traits such as plant height, number of flowers, number of days to flowering, number of daughter bulb, proline content, ion leakage, leaf relative water content and lipid peroxidation in leaf. Results of mean comparison of data showed that S1 treatment, had the highest concentrations of macro elements, had a positive effect on vegetative characteristics such as length of largest flower bud, leaf length and width, leaf number and weight of daughter bulb as well as biochemical parameters like anthocyanin and protein in petal, chlorophyll in leaf, and concentration of mineral elements of nitrogen, phosphorus, potassium, calcium and magnesium in the leaf of lily cut flower in soilless culture conditions. [ABSTRACT FROM AUTHOR]

مقدمه گندم ازنظر تولید و سطح زیر کشت مهم‌ترین محصول کشاورزی ایران است و مشکل علف­ هرز در آن شاید یکی از مهم‌ترین مسائل زراعی در نقاط گندم ­خیز جهان باشد (Kafi et al., 2005). چاودار گیاهی یک‌ساله با ساقه­ های بلند است که در کشور به‌صورت گیاه­ هرز در مزارع گندم دیده می­شود (Krimi, 2004). توقعات کم این گیاه همراه با توانایی دگر­آسیبی و مورفولوژی و چرخه زندگی مشابه گندم، باعث پایداری و افزایش سطح آن در مزارع گندم پاییزه شده است (Pester et al., 2000). رقابت از موضوعات کلیدی در مباحث اکوفیزیولوژیک جوامع گیاهی است؛ در این نوع تداخل علف‌های هرز از طریق هم‌جواری با گیاه زراعی، برای جذب منابع نور، آب و مواد غذایی به رقابت پرداخته و رشد و نمو و عملکرد گیاهان زراعی را تحت تأثیر قرار می­دهند (Evans et al., 2003). با توجه به محدودیت­های شدید منابع آبی در اکثر مناطق کشور، تنش خشکی به‌عنوان مهم‌ترین تنش تأثیرگذار بر گیاهان زراعی معرفی شده است (Kafi et al., 2009). نتیجه رقابت هم با منابع و هم با شرایط محیطی تحت تأثیر قرار می­گیرد، رقابت بین علف‌های هرز و گیاهان زراعی بر سر آب سبب کاهش رطوبت موجود در خاک شده که می­تواند باعث تنش آب و درنهایت کاهش رشد علف‌های هرز و عملکرد گیاهان زراعی شود. مطالعاتی که مکانیسم‌های ممکن رقابت برای آب را مورد آزمایش قرار دهد، زیاد نیستند. اغلب این مطالعات در شرایط کنترل‌شده محیطی انجام‌گرفته است. بااین‌وجود، این مطالعات بینشی را در مورد مکانیسم‌های ممکن رقابت برای آب، به وجود آورده­اند (Zand et al., 2004). مواد و روش­ ها به‌منظور بررسی تأثیر رقابت درون و برون گونه­ ای بر برخی صفات مرفولوژیکی و رشدی گندم و چاودار تحت شرایط تنش خشکی، مطالعه­ای در سال 1391 در گلخانه تحقیقاتی دانشکده کشاورزی دانشگاه بیرجند به‌صورت فاکتوریل سه عاملی در قالب طرح کاملاً تصادفی با 3 تکرار اجرا شد. فاکتور­های آزمایش شامل چهار تراکم گندم رقم روشن (0، 8، 16 و 24 بوته در گلدان)، چهار تراکم چاودار (0، 2، 4 و 6 بوته در گلدان) و دو سطح تنش خشکی شامل آبیاری در 20 و 60% تخلیه رطوبت ظرفیت زراعی خاک بود. صفات تعداد برگ و کلروفیل برگ گندم و چاودار در زمان ظهور سنبله‌های گندم، ارتفاع آن‌ها، طول پدانکل (دمگل)، طول سنبله و قطر ساقه گندم در 95 روز بعد از کاشت (انتهای دوره رشد) اندازه‌گیری شد. نتایج و بحث نتایج نشان داد که افزایش تراکم گندم و چاودار موجب کاهش معنی‌دار ارتفاع گیاه (به ترتیب حداکثر 51.23 و 39.13 درصد در گندم و 45.24 و 56.6 درصد در چاودار)، تعداد برگ (حداکثر80.35 و 73.30 درصد در گندم و 37.71 و 71.31 درصد در چاودار) و شاخص کلروفیل برگ (حداکثر 12 و 38.11 درصد در گندم و 75.13 و 38.0 درصد در چاودار) شد. تنش خشکی نیز باعث کاهش معنی­دار ارتفاع (58.17 درصد در گندم و 64.7 درصد در چاودار) و تعداد برگ (48.8 درصد در گندم و 75.26 درصد در چاودار) و افزایش معنی‌دار شاخص کلروفیل برگ (20 درصد در گندم و 78.7 درصد در چاودار) شد. افزایش تنش خشکی طول سنبله گندم را تحت تأثیر معنی­دار قرار نداد، اما طول پدانکل (دمگل) و قطر ساقه گندم را به ترتیب 03.26 و 49.3 درصد کاهش داد. با افزایش تراکم چاودار و گندم طول سنبله گندم (به ترتیب حداکثر 70.13 و 21.24 درصد)، طول پدانکل گندم (39.17 و 72.22 درصد) و قطر ساقه گندم (11.11 و 18 درصد) به‌طور معنی­ داری کاهش یافت. نتیجه­ گیری نتایج به‌طورکلی نشان داد در شرایط تنش خشکی، رقابت درون­ گونه­ ای فقط بر ارتفاع گندم اثر معنی­دار داشت، ولی اثر رقابت برون­ گونه­ ای بر شاخص کلروفیل و تعداد برگ گندم و ارتفاع و تعداد برگ چاودار معنی­ دار بود. در نتیجه حضور توأم تنش خشکی و رقابت­ های گیاهی باعث کاهش هر چه بیشتر این صفات گردید همچنین درصد کاهش آن‌ها در گندم بیشتر از چاودار بود. درنتیجه در مناطقی که علف­ هرز چاودار به‌عنوان علف­ هرز مهم مزارع گندم باشد، در هنگام بروز تنش خشکی، خسارت چاودار بیشتر خواهد شد لذا کنترل آن در شرایط محدودیت رطوبتی از اهمیت خاصی برخوردار است.

The final leaf number is an important morphological characteristic of maize (Zea mays L.) and is therefore an important input parameter in some maize crop models. In this study, field experiments were conducted from 2013 to 2016 at 23 sites across China, which were located between latitudes of 26°30′ and 46°45′ N, focusing on five modern maize cultivars, in order to determine the amplitude of variation in mean leaf numbers between each cultivar, identify differences between the mean leaf numbers of cultivars under different climatic conditions, and clarify the effects of the differences in final leaf numbers on aboveground dry matter (DM) and grain yield. The results showed that the mean final leaf numbers increased in the order of XY335 < NH101 < ZD909 < ZD958 < DH11 among the five cultivars, with the wide distribution ranges of final leaf numbers being 17.0–23.3 (DH11), 16.7–22.3 (ZD958), 16.7–22.0 (ZD909), 16.7–22.3 (NH101), and 17.0–22.0 (XY335) across all locations. In addition, leaf numbers above and below the primary ear showed the same trends with the mean final leaf numbers for the same cultivars. Many climatic factors were found to significantly affect the final leaf numbers across four maize-growing regions in China, and the result of stepwise regression indicated that the influences of photoperiod and temperature, in particular, were greater than other climatic factors for these cultivars. Finally, there were found to be significant and positive relationships between the final leaf number and (1) the maximum leaf area index (LAImax), (2) DM at both silking and physiological maturity, and (3) grain yield for the same cultivars across all locations. The results of this study are of great importance for guiding future trans-regional maize cultivation and further model calibration.

Let G be a simple connected, paw-free graph with minimum degree δ, leaf number L(G) and order n. We show for δ≥3 that L(G)≥13n+43 and the bound is sharp. Further, if G is claw-free, paw-free, we prove for δ≥3 that L(G)≥n2+12, and for δ≥5 we prove that L(G)≥47n+67. The results apart from improving some of the results in Griggs et al. (J Graph Theory 13:669-695, 1988), Griggs and Wu (Discrete Math 104:167-183, 1992), Kleitman and West (SIAM J Discrete Math 4, 99-106, 1991), provide new lower bounds on leaf number whose practical applications in network designs are legion. [ABSTRACT FROM AUTHOR]

This study was organised to check the effect of silver nanoparticles and silver nitrate on rice growth against biotic stress. Silver nanoparticles were synthesised by using plant extract as reducing agent, followed by characterisation through UV Vis spectroscopy, XRD, EDS and SEM. Aspergillus application significantly reduced rice plant fresh mass (0.9%), dry mass (0.21%), root length (2.3%), shoot length (5.2%) and root number (1%) in comparison to control. Similarly, leaf area, leaf fresh mass, dry mass and leaf number were also reduced by 23.1, 0.02, 0.11 and 0.9%, respectively. AgNPs and AgNO3 treatments increased the root length (16.2 & 12.8%), shoot length (21 & 20%), root number (8.1 & 6.8%), plant fresh weight (6.4 & 5%) and plant dry weight (4.6 & 3.5%) in 75mg/l treatment of AgNPs and AgNO3 respectively. Similarly, AgNPs and AgNO3 treatment (75 mg/l concentrations) reflected remarkable increase in leaf area (58.8 & 57.2 %), leaf number (4.3 & 3.7 %), leaf fresh weight (1.7 & 1.4 %) and leaf dry weight (0.9 & 0.8 %). Overall AgNPs showed more significant results as compared to AgNO3. The quantity of aflatoxins ranged from 3.1 to 7.7 μg/kg against tolerable limit (4 µg/kg). Overall AgNPs and AgNO3 treatments showed significant results and it could be considered as a strategy for aflatoxin management in rice plants. [ABSTRACT FROM AUTHOR]

[Objective] The effects of soil water content and light intensity on the leaf flexibility of flue-cured tobacco leaves under different leaf number were studied. [Method] Through the greenhouse experiment set,the number of leaves (18, 20, 22) ,different soil moisture content (more 40 % or less 20 %) , and different light intensity (shading, no shading) ,the leaf flexibility of all parts of flue-cured tobacco K326 was studied. [Result] In tin; ease of a certain number of leaves, the lower tin; soil water content was, the less the light was, tin; shorter tin; growth period of flue-cured tobacco was, tin; worse tin; growth the lower the flexibility of tin; flue-cured tobacco leaves was,and tin; more prone to the phenomenon of broken leaves was. [Conclusion] When the flue-cured tobacco was in the environmental condition with the phenomenon of broken leaves, it was necessary to reduce the effective leaf number to improve the flexibility of the leaves to a certain extent so as to achieve the purpose of preventing tin; occurrence of broken leaves. [ABSTRACT FROM AUTHOR]

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