Search

Leaf ontogenesis is imperative for the establishment and regulation of its structural and functional properties, in addition to being an excellent tool for assigning specimens to different groups of angiosperms. Even though the importance of leaf morphology and anatomy for taxonomic use is well known, few studies have addressed the processes of leaf ontogeny in Melastomataceae. Herein, we sought to define the ontogenetic steps of leaves of Trembleya phlogiformis DC., highlighting the indumentum, to understand the main functional traits. Shoot apex, young, and fully expanded leaves were processed by typical light microscopy procedures. At the first node, leaf primordia are densely covered with trichomes and emergences. The adaxial layer of ground meristem gives rise to the palisade parenchyma, the procambium originates from median layers of ground meristem, and the spongy parenchyma develops from abaxial layers of ground meristem. The differentiation of isobilateral mesophyll on leaves of T. phlogiformis, a common feature in Microlicieae, comes from ground meristem stratification. However, T. phlogiformis stands out by showing cells with irregular shapes in the leaf mature spongy parenchyma. The leaf ontogeny reveals distinct mechanisms of cell differentiation and may be important for the establishment of functional adaptive traits.

Copper (Cu) contents in vineyard soils due to the application of cupric fungicides cause changes in the native covering flora. Under these conditions, the surviving individuals accumulate the metal in and decrease its availability in the soil, reducing the potential toxicity to grapevine. We have identified spontaneous plant species and their phytoremediation potential from vineyards of Isabella (Vitis labrusca) on two distinct soil types (Inceptisol and Entisol) contaminated with Cu. The results demonstrated that wild species displayed higher Cu contents in the roots than in the shoot, but had low bioaccumulation potential. During summer, the plants were unable to extract and stabilize the metal, although during the winter, Lolium multiflorum, Cyperus compressus and Chrysanthemum leucanthemum demonstrated phytostabilization potential. Among the investigated species, dry matter production and Cu accumulation by Lolium multiflorum indicated that the species is effective to decrease Cu availability in the soil. Made available in DSpace on 2022-07-12T19:19:53Z (GMT). No. of bitstreams: 1 melo202-p341-3491.pdf: 1213731 bytes, checksum: 02d31dab3c4f48cd3b4aaba2a784fbd5 (MD5) Previous issue date: 2021

Using tolerant genotypes and the correct use of fertilizers can mitigate the negative effect of elevated Cu levels in the growing medium. In this context, the study aimed to evaluate the effects of excess Cu in the root system and the effectiveness of phosphorus (P) in minimizing the phytotoxicity of Cu in three genotypes: IAC 572 [(Vitis riparia x V. rupestris) x V. caribaea], Magnolia (V. rotundifolia) and Paulsen 1103 (V. berlandieri x V. rupestris). The plants were grown in nutrient solutions and were supplemented with the following treatments: 0.3 μM Cu (Control), 60 μM Cu (Cu) and 60 μM Cu and 62 mg L

The increase in zinc (Zn) content in orchard soils caused by successive applications of fertilizers and fungicides to control foliar diseases can modify the structure of the roots of young peach trees. The study aimed to evaluate the effect of the application of Zn doses in soil on the morphological and anatomical structure of the roots and on the growth of young peach plants grafted on three clonal rootstock cultivars. Samples of a Typic Hapludalf were collected, air dried, sieved and subjected to the application of 0, 60 and 120 mg Zn kg−1. After the incubation period, one plant of each rootstock cultivar (Flordaguard, Rigitano and Tsukuba-1) was transplanted into rhizoboxes and grown for 65 days. In the shoots, we determined dry matter production and Zn concentration in tissue. In the roots, we analyzed root morphology using light microscopy. The increase in the availability of Zn in the soil stimulated the production and accumulation of phenolic compounds in the cortex and vascular cylinder of the roots, in addition to increasing the concentration of Zn in plant tissue to values ​​above those considered normal. Rigitano and Tsukuba-1 rootstock cultivars exhibited cell rupture in the cortex, resulting in the formation of intercellular spaces. Flordaguard rootstock cultivar was the least sensitive to morphological and anatomical changes in the root apex and, therefore, may be the most recommended for cultivation in soils with high Zn contents.

Made available in DSpace on 2022-04-28T19:08:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Universidade Federal de Uberlândia In Microlicieae taxonomical delimitation of Lavoisiera, Microlicia and Trembleya is problematic. This study aims to fill this gap by identifying leaf characters that are useful for taxonomy of these genera. Species of Rhynchanthera were also included in this study for comparison, since it is an early-diverging genus of the tribe. Diagnostic characters of Lavoisiera include sessile leaves with spongy parenchyma composed of isodiametric cells, and acute margins with supporting tissue. Trembleya is distinguished by petiolate, microphyllous, and hypostomatic leaves. The presence of depressions on the leaf surface and a homogeneous mesophyll is observed only in species of Microlicia. The leaf characters observed in Rhynchanthera, together with the available phylogenetic studies, were important to indicate evolutionary tendencies in the leaf structure within Microlicieae. Thus, our results indicate a tendency for reduction in leaf size within the tribe, in relation to both the petiole and the lamina. This reduction, which is more pronounced in Microlicia, results in a greater anatomical heterogeneity, due to variations in the organization of both vascular and fundamental tissues. Programa de Pós-graduação em Biologia Vegetal Universidade Federal de Uberlândia Instituto de Biologia Programa de Pós-graduação em Ciências Biológicas (Biologia Vegetal) Universidade Estadual Paulista Instituto de Biociências Departamento de Botânica, Av 24A, 1515 Universidade Federal de Uberlândia Instituto de Biologia Rua Ceará s.n., Bloco 2D Universidade Federal de Santa Maria Departamento de Biologia, Avenida Roraima, 1000, Cidade Universitária Programa de Pós-graduação em Ciências Biológicas (Biologia Vegetal) Universidade Estadual Paulista Instituto de Biociências Departamento de Botânica, Av 24A, 1515

Two new species of Microlicia (Melastomataceae) endemic to campos rupestres from the Espinhaco mountain range in Minas Gerais, Brazil, are described and illustrated, and a discussion on leaf anatomy is also provided. Microlicia cogniauxiana is similar to M. graveolens, M. passerina, and M. tomentella by having an indumentum of stalked glands, pink to pink-magenta petals, and dimorphic stamens with bicolored anthers. It can be distinguished by its leaves with noticeable veins on the adaxial surface, and glandular-ciliate margins. Microlicia naudiniana is similar to M. nervosa, but can be distinguished by its sessile leaves with a conspicuously visible midrib on the abaxial surface and petals with rounded apex and revolute margin. It differs from M. passerina by having a sparser indumentum covering the entire plant.

Successive applications of copper-based (Cu) fungicides have increased Cu concentration in vineyard soils, inducing Cu toxicity in young vines and cover crops such as black oat, thus inhibiting growth and development. However, increasing soil phosphorus (P) content can reduce Cu toxicity symptoms. In this context, the aim of this study was to evaluate the effect of Cu toxicity and its alleviation by P fertilization in black oat cultivated in sandy soil. For the experiment, Typic Hapludalf soil samples were air-dried, prepared, and subjected to increasing doses of Cu (0, 30, and 60 mg kg−1) and P (0 and 100 mg kg−1). Subsequently, the soil was incubated and stored in pots, where black oat seedlings were grown for 30 days in a greenhouse. Plant roots subjected to Cu, especially with the highest Cu concentration and without P addition decreased the root cap size, showing early tissue differentiation and lateral root formation near the apical region. Decrease in dry matter (DM) production of roots (50 %) and shoots (67 %) was also observed in the highest Cu concentration. Plants without P addition, regardless of Cu concentration, also had lower root (33 %) and shoot (65 %) DM production. P addition in soil and its increased concentration reduced root anatomical changes and stimulated plant DM production. Therefore, we conclude that excessive Cu concentration alters black oat root anatomical structure, affecting plant growth, especially in sandy soils with low organic matter content. However, P supply can reduce root Cu toxicity symptoms, thus increasing plant dry matter production.

High copper (Cu) soil contents, due to the continuous vineyard application of Cu fungicides throughout the years, may impair the growth of the shoot and modify the structure of the root system. The current study aimed to investigate the threshold levels of available Cu in the soil causing toxicity effects in young grapevine plants of ‘Red Niagara’ cultivated in clay soils. Grapevine plantlets were cultivated in pots containing vineyard devoted soils with increasing contents of available Cu (25, 80, 100 and 165 mg kg?1 ), for 53 days. Photosynthesis and transpiration rates, and the quantum yield of photosystem II (Fv/Fm) were evaluated during the cultivation period. At the end of the experiment, the plant nutrient and leaf chlorophyll were determined, along with the anatomical analysis of the root system structure and plant dry matter determination. Higher levels of available Cu in the soil increased the apoplastic, symplastic and total fraction of the metal in the roots, reducing the other nutrients, especially in the shoots. Photosynthesis, transpiration rates and Fv/Fm were also reduced. Higher levels of Cu led to anatomical changes in the roots, that increased diameter, number of layers in the cortex, vascular cylinder and total root areas. It also resulted in reduced dry matter production by grapevines. Keywords: Available Cu Net photosynthesis Maximum quantum yield Root diameter Vitis labrusca L Made available in DSpace on 2019-01-11T00:04:58Z (GMT). No. of bitstreams: 1 Highcoppercontentinvineyardsoilspromotesmodi64257cationsin.pdf: 1434017 bytes, checksum: 77453d1f9f03c8da1881ad6ee30af116 (MD5) Previous issue date: 2019-01-09