An easy and reliable method for establishment and maintenance of leaf and root cell cultures of Arabidopsis thaliana

Cell suspension cultures are useful for a wide range of biochemical and physiological studies, yet their production can be technically demanding and often unreliable. Here we describe a protocol for producing Arabidopsis cell suspension cultures that is reliable and easy to use.

Coffee leaf and stem anatomy under boron deficiency

Boron deficiency in coffee is widely spread in Brazilian plantations, but responses to B fertilizer have been erratic, depending on the year, form and time of application and B source. A better understanding of the effects of B on plant physiology and anatomy is important to establish a rational fertilization program since B translocation within the plant may be affected by plant anatomy. In this experiment, coffee plantlets of two varieties were grown in nutrient solutions with B levels of 0.0 (deficient), 5.0 µM (adequate) and 25.0 µM (high). At the first symptoms of deficiency, leaves were evaluated, the cell walls separated and assessed for B and Ca concentrations. Scanning electron micrographs were taken of cuts of young leaves and branch tips. The response of both coffee varieties to B was similar and toxicity symptoms were not observed. Boron concentrations in the cell walls increased with B solution while Ca concentrations were unaffected. The Ca/B ratio decreased with the increase of B in the nutrient solution. In deficiency of B, vascular tissues were disorganized and xylem walls thinner. B-deficient leaves had fewer and deformed stomata.

Leaf and root volatiles produced by tissue cultures of Alpinia zerumbet (pers.) Burtt & Smith under the influence of different plant growth regulators

Volatiles produced by plantlets of Alpinia zerumbet were obtained by means of simultaneous distillation-extraction (SDE). The effects of indole-3-acetic acid, kinetin, thidiazuron and 6-benzylaminopurine on leaf and root volatile composition obtained by tissue cultures were investigated. A higher content of b-pinene and a lower content of sabinene were observed in leaf volatile of plantlets cultured in control, IAA and IAA+ TDZ media, as compared with those of donor plants. In vitro conditions were favorable to increase caryophyllene content. Volatile compounds from the root were characterized mainly by camphene, fenchyl-acetate and bornyl acetate; which constitute about 60% of total volatile.

Coffee leaf and stem anatomy under boron deficiency

A deficiência de B é muito comum nos cafezais brasileiros, mas as respostas do cafeeiro ao B têm sido erráticas, dependendo do ano, do modo e época de aplicação e, ainda, da fonte de B empregada. Um melhor entendimento dos efeitos do B na fisiologia e anatomia do cafeeiro é importante para o desenvolvimento de um programa racional de adubação boratada, uma vez que a anatomia da planta pode influenciar a translocação do nutriente. Neste experimento, plantas de dois cultivares foram cultivadas em soluções nutritivas com 0,0 (deficiente), 5,0 (adequado) e 25,0 µM (alto) de B. Quando os primeiros sintomas de deficiência apareceram, as folhas foram cortadas e tiveram suas paredes celulares isoladas e analisadas quanto aos teores de B e Ca. Cortes foram feitos em folhas novas e no ápice de ponteiros e fotografados em microscópio eletrônico de varredura. A resposta dos dois cultivares ao B foi semelhante, não tendo sido observados sintomas de toxidez. O teor de B nas paredes celulares foi aumentado com o incremento da concentração desse elemento na solução, enquanto o teor de Ca não foi afetado. A relação Ca/B decresceu com o aumento da concentração de B na solução. Com deficiência de B, os tecidos vasculares foram desorganizados e as paredes do xilema ficaram mais finas. Folhas de café com deficiência deste nutriente apresentaram menos estômatos, os quais se encontravam.

Leaf and stem anatomy of Vochysiaceae in relation to subfamilial and suprafamilial systematics

Several leaf anatomical features are potentially systematically informative within both the family Vochysiaceae and the order Myrtales, notably tracheoidal idioblasts, mucilage cells and secretory canals. Tracheoids with spiral wall thickenings are present in the mesophyll of most species of Vochysia, and also occur in several other families of Myrtales. Mucilage cells are common in the leaf epidermis in some Vochysiaceae. Secretory ducts are present in the midrib in Salvertia and Vochysia, which are apparently closely related, although Salvertia also shares some leaf anatomical characters with Qualea and Callisthene. Anatomical data do not support the segregation of Ruizterania from Qualea; leaves of R. albiflora leaves are very similar to those of Q. paraensis in venation pattern, and leaf and stem anatomy. Different venation patterns are characteristic of sections within the genus Qualea, but within the large genus Vochysia, leaf anatomy is variable even within a subsection. Amongst other Myrtales, leaf anatomy of Vochysiaceae most closely resembles that of Combretaceae and Onagraceae. © 2002 The Linnean Society of London.

Host genotype and age shape the leaf and root microbiomes of a wild perennial plant.

Bacteria living on and in leaves and roots influence many aspects of plant health, so the extent of a plant's genetic control over its microbiota is of great interest to crop breeders and evolutionary biologists. Laboratory-based studies, because they poorly simulate true environmental heterogeneity, may misestimate or totally miss the influence of certain host genes on the microbiome. Here we report a large-scale field experiment to disentangle the effects of genotype, environment, age and year of harvest on bacterial communities associated with leaves and roots of Boechera stricta (Brassicaceae), a perennial wild mustard. Host genetic control of the microbiome is evident in leaves but not roots, and varies substantially among sites. Microbiome composition also shifts as plants age. Furthermore, a large proportion of leaf bacterial groups are shared with roots, suggesting inoculation from soil. Our results demonstrate how genotype-by-environment interactions contribute to the complexity of microbiome assembly in natural environments.

Biochemical and histological characterization of tomato mutants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biochemical and histological characterization of tomato mutants

Biochemical responses inherent to antioxidant systems as well morphological and anatomical properties of photomorphogenic, hormonal and developmental tomato mutants were investigated. Compared to the non-mutant Micro-Tom (MT), we observed that the malondialdehyde (MDA) content was enhanced in the diageotropica (dgt) and lutescent (l) mutants, whilst the highest levels of hydrogen peroxide (H2O2) were observed in high pigment 1 (hp1) and aurea (au) mutants. The analyses of antioxidant enzymes revealed that all mutants exhibited reduced catalase (CAT) activity when compared to MT. Guaiacol peroxidase (GPOX) was enhanced in both sitiens (sit) and notabilis (not) mutants, whereas in not mutant there was an increase in ascorbate peroxidase (APX). Based on PAGE analysis, the activities of glutathione reductase (GR) isoforms III, IV, V and VI were increased in l leaves, while the activity of superoxide dismutase (SOD) isoform III was reduced in leaves of sit, epi, Never ripe (Nr) and green flesh (gf) mutants. Microscopic analyses revealed that hp1 and au showed an increase in leaf intercellular spaces, whereas sit exhibited a decrease. The au and hp1 mutants also exhibited a decreased in the number of leaf trichomes. The characterization of these mutants is essential for their future use in plant development and ecophysiology studies, such as abiotic and biotic stresses on the oxidative metabolism.

Aluminum in corn plants: influence on growth and morpho-anatomy of root and leaf

Aluminum (Al) toxicity is one of the most limiting factors for productivity. This research was carried out to assess the influence of Al nutrient solution on plant height, dry weight and morphoanatomical alterations in corn (Zea mays L.) roots and leaves. The experiment was conducted in a greenhouse with five treatments consisting of Al doses (0, 25, 75, 150, and 300 µmol L-1) and six replications. The solutions were constantly aerated, and the pH was initially adjusted to 4.3. The shoot dry matter, root dry matter and plant height decreased significantly with increasing Al concentrations. Compared to the control plants, it was observed that the root growth of corn plants in Al solutions was inhibited, there were fewer lateral roots and the development of the root system reduced. The leaf anatomy of plants grown in solutions containing 75 and 300 µmol L-1 Al differed in few aspects from the control plants. The leaf sheaths of the plants exposed to Al had a uniseriate epidermis coated with a thin cuticle layer, and the cells of both the epidermis and the cortex were less developed. In the vascular bundle, the metaxylem and protoxylem had no secondary walls, and the diameter of both was much smaller than of the control plants.

Aluminum in corn plants: influence on growth and morpho-anatomy of root and leaf

A toxicidade do alumínio (Al) é um dos fatores mais limitantes para a produtividade. Esta pesquisa foi realizada para avaliar a influência do Al, em solução nutritiva, na altura de plantas, no peso da matéria seca e nas alterações morfoanatômicas de raízes e folhas de milho (Zea mays L.). O experimento foi conduzido em casa de vegetação com tratamentos constituídos de cinco doses de Al (0; 25; 75; 150; e 300 µmol L-1) e seis repetições. As soluções foram constantemente aeradas e o pH foi ajustado a 4,3, inicialmente. A matéria seca da parte aérea e das raízes e a altura das plantas diminuíram significativamente com o aumento da concentração de Al. As raízes de plantas de milho cultivadas em soluções com Al tiveram seu crescimento inibido e apresentaram menos raízes laterais e desenvolvimento do sistema radicular inferior, em comparação com as das plantas-controle. As folhas das plantas crescidas em soluções que continham 75 e 300 µmol L-1 de Al não apresentaram muita diferença anatômica em relação às das plantas-controle. A bainha da folha das plantas exposta ao Al apresentou epiderme uniestratificada revestida por uma fina camada de cutícula e as células da epiderme e do córtex foram as que menos se desenvolveram. No feixe vascular, o metaxilema e protoxilema não tinham paredes secundárias, e o diâmetro de ambos foi muito menor quando comparado com os das plantas-controle.

Changes in anatomy and root cell ultrastructure of soybean genotypes under manganese stress

The deleterious effects of both Mn deficiency and excess on the development of plants have been evaluated with regard to aspects of shoot anatomy, ultrastructure and biochemistry, focusing mainly on the manifestation of visual symptoms. However, there is little information in the literature on changes in the root system in response to Mn supply. The objective of this study was to evaluate the effects of Mn doses (0.5, 2.0 and 200.0 μmol L-1) in a nutrient solution on the anatomy of leaves and roots of the Glycine max (L.) cultivars Santa Rosa, IAC-15 and IAC-Foscarin 31. Visual deficiency symptoms were first observed in Santa Rosa and IAC-15, which were also the only cultivars where Mn-toxicity symptoms were observed. Only in IAC-15, a high Mn supply led to root diameter thickening, but without alteration in cells of the bark, epidermis, exodermis and endodermis. The degree of disorganization of the xylem vessels, in particular the metaxylem, differed in the cultivars. Quantity and shape of the palisade parenchyma cells were influenced by both Mn deficiency and toxicity. A reduction in the number of chloroplasts was observed in the three Mn-deficient genotypes. The anatomical alterations in IAC-15 due to nutritional stress were greater, as expressed in extensive root cell cytoplasm disorganization and increased vacuolation at high Mn doses. The degree of changes in the anatomical and ultrastructural organization of roots and leaves of the soybean genotypes studied differed, suggesting the existence of tolerance mechanisms to different intensities of Mn deficiency or excess.

Leaf mineral composition of grafted eggplant grown in soil infested with Verticillium and root-knot nematodes

The objective of this work was to determine differences in leaf mineral composition between ungrafted and grafted onto (Solanum torvum) eggplant (Solanum melongena), cultivars 'Faselis' and 'Pala', grown in a soil infested with Verticillium dahliae and Meloidogyne incognita, or in a noninfested soil. Grafting increased leaf P and Mn concentrations, and decreased N concentrations, in both soils. Grafting also enhanced leaf Ca concentration of 'Pala', but it did not affect that of 'Faselis' depending on the cropping year. Leaf Mg concentration of grafted plants in infested soil was lower than that of ungrafted ones in noninfested soil. Results showed that, under the same fertilization program, the grafted 'Faselis' plants used the nutrients more efficiently than the 'Pala' ones. Use of S. torvum as a rootstock for 'Faselis' resulted in an effective protection against multiple pathogen infestation. Fertilization may be necessary when grafted 'Faselis' plants are grown in a soil infested with the pathogens, since grafting and infestation generally decrease leaf N, Mg, Ca and Fe concentrations, either by reducing the nutrient concentrations directly or by increasing leaf Mn concentration.

Leaf blade quantitative anatomy of sugarcane cultivars and clones

The objective of this study was to make a quantitative assess of the anatomic characteristics of leaf blade of the sugarcane cultivars RB855113, SP80-1842, SP80-1816, RB867515 and clone RB957689 presenting different sensitivity to the mixture of sodium trifloxysulfuron + ametryn herbicides. Compared to the other cultivars assessed, RB855113 cultivar, considered more sensitive to the herbicide mixture, presented relevant differences such as greater proportion of bulliform cells, greater tissue proportion in the transverse section of the leaf blade, greater stomata and trichome density on both surfaces, thinner epidermis on the adaxial surface and length of stomata on both surfaces. The external paraclinal wall of the bulliform cells was thinner than in the common epidermis cells in all the genotypes on the adaxial and abaxial surfaces. Multivariate analysis of the data on the variables considered most relevant to explain the herbicide penetration singled out the sensitive RB855113 from the other materials. Such characteristics can explain the greater penetration, and consequently, greater sensitivity of this cultivar to the sodium trifloxysulfuron + ametryn mixture.

Comparative wood anatomy of root and stem in Styrax camporum (Styracaceae)

Styrax camporum Pohl is a shrub common in the cerrado vegetation of south-eastern Brazil. Root and stem wood in Styrax camporum differ quantitatively and qualitatively. Quantitative differences follow normal expectations: roots have wider and longer vessel elements, a lower vessel frequency, a lower ray frequency, and wider rays. Qualitative features of the roots are: simple perforation plates, vestured pits, and septate libriform fibres; qualitative features of the stems are: multiple perforation plates, non-vestured pits, and non-septate fibre-tracheids. Based on generally accepted evolutionary trends, root wood of Styrax camporum has more specialized features than stem wood. Additional comparative studies of stem and root anatomy are needed to determine if such differences between root and stem anatomy are widespread, and consistent with the lines of specialization observed in monocotyledons.

Leaf and inflorescence peduncle anatomy: a contribution to the taxonomy of Rapateaceae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)