ABSTRACT The objective of this research was to evaluate the biochemical and physiological quality of peanut cultivar seeds under periods of imbibition and drying. A completely randomized statistical design was adopted, in factorial scheme, with four replications. The three peanut cultivars were: BR1, BRS 151-L7, and IAC 505. The imbibition and drying periods were: 0, 12, 24, 36 and 48 hours. The seeds were imbibition with the aid of germitest paper and distilled water, then dried on a metal screen in a plastic box with silica, according to the periods studied. Physiological variables were evaluated (percentage of germination, normal seedlings, abnormal seedlings in the first count and abnormal seedlings in the final count, accelerated aging, seedling length, electrical conductivity, speed index, and average germination time) and biochemical variables (sugar concentration total, reducing sugars, hydrogen peroxide, total superoxide dismutase proteins, and total proteins). The desiccation tolerance of peanut seeds is reduced as the period of water absorption followed by drying increases. Seeds of cultivar IAC 505 have greater tolerance to imbibition and subsequent desiccation compared to seeds of BR1 and BRS 151-L7. adopted scheme replications BR 151L7, 151L7 L 151 L7, L7 151-L7 0 12 24 3 4 hours silica studied percentage aging length conductivity index time sugar sugars peroxide proteins proteins. . proteins) increases 50 151L7. L7. 151L 15 151-L 1 2 5

Abstract Sugarcane cultivar RB0442 has a high yield, late maturation and good drought tolerance. It is recommended for planting in restrictive environments, mainly with water-deficient soils, and is resistant to the major sugarcane diseases of the Northeastern region of Brazil.

RESUMO: O objetivo do estudo foi analisar a expressão de genes de referência em cana-de-açúcar sob estresse hídrico. As cultivares RB72454 e RB72910 foram cultivadas em campo e os tratamentos controle e estresse foram aplicados após 135 dias. O estresse das plantas foi mensurado utilizando as variáveis fisiológicas: taxa fotossintética, transpiração e condutância estomática. Para cada repetição biológica, a expressão gênica foi conduzida usando PCR tempo real para os genes α-tubulina, β-tubulina, β-actina, ciclofilina, fator 1 de alongamento eucariótico, gliceraldeído 3-fosfato desidrogenase (GAPDH), histona H3 e ubiquitina. A estabilidade dos genes foi avaliada usando os softwares geNorm,NormFinder e BestKeeper. Entre os genes candidatos, GAPDH foi identificado como o mais estável nos três métodos de análises, indicando ser estável para estudos de expressão gênica em cana-de-açúcar sob estresse hídrico; seguindo o gene β-actina como o segundo mais estável. Os resultados concluem que os genes GAPDH e β-actina são indicados para normalização em expressão gênica relativa, associada com estresse hídrico em cana-de-açúcar.

ABSTRACT: The aim of this study was to analyze the expression of putative reference genes in sugarcane under drought stress. The varieties RB72454 and RB72910 were cultivated and the treatments control and drought stress applied to 135-day-old plants grown under field conditions. The stress level of the plants was measured by rate of photosynthesis, transpiration, and stomatal conductance. For each biological replicate, expression analyses were conducted using quantitative polymerase chain reaction for the genes α-tubulin, β-tubulin, β-actin, cyclophilin, eukaryotic elongation factor 1, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), histone H3 and ubiquitin. Stability was evaluated using the geNorm, NormFinder, and BestKeeper software packages. Among the candidate genes, GAPDH was identified as the most stable in all software, indicating its suitability for gene expression studies in sugarcane undergoing drought stress; the gene β-actin was the second most stable. These findings suggest using GAPDH and β-actin for normalization in relative gene expression in sugarcane.

RESUMO O cultivo de Jatropha curcas visando a produção de biodiesel é uma possibilidade para o uso de áreas salinizadas, no entanto a produção de biomassa nesses solos é limitada. Os fungos micorrízicos arbusculares (FMAs) são uma alternativa promissora para a biorremediação em solos salinizados. Porém, a salinidade também afeta os FMAs, no momento da colonização e, neste caso, nem sempre a simbiose se estabelece. Portanto, este estudo teve como objetivo testar as hipóteses de que três espécies de FMAs comummente encontradas em solos salinos se associam à J. curcas e, se mudas previamente inoculadas com esses FMAs são mais tolerantes ao estresse salino. Foram realizados dois experimentos, o primeiro, em delineamento inteiramente casualizado com cinco tratamentos (controle, Rhizophagus intraradices, Gigaspora albida, Claroideoglomus etunicatum e as três espécies em conjunto) com seis repetições, com o objetivo de investigar a formação da simbiose entre as espécies, e um segundo, realizado em blocos casualizados, em esquema fatorial 4 x 2 (2, 5, 8 e 10 dS m-1, com e sem micorrizas), com oito repetições, para a verificação do desenvolvimento e dependência micorrízica (DM) das mudas previamente inoculadas, em ambiente salinizado. As três espécies de FMAs se associam a J. curcas, isoladamente e em conjunto. A DM aumentou com a salinidade, indicando que J. curcas é uma espécie facultativa. As mudas pré-colonizadas com FMA são uma alternativa para o estabelecimento de J. curcas em solos salinizados.

ABSTRACT The cultivation of Jatropha curcas L. for biodiesel production is possible in salinized areas; however, biomass production is limited in these soils. Arbuscular mycorrhizal fungi (AMF) are a promising alternative for bioremediation in salinized soils. Yet, salinity also affects the AMF at the time of colonization and, in this case, the symbiosis is not always established. Therefore, the aim of this study was to test the hypotheses that three AMF species commonly found in saline soils are associated with J. curcas and if seedlings previously inoculated with these AMF are more tolerant to salt stress. Two trials were performed: the first one was carried out in a completely randomized design with five treatments (control, Rhizophagus intraradices, Gigaspora albida, Claroideoglomus etunicatum, and the three species together) and six repetitions to investigate the formation of symbiosis among species; and the second trial was carried out in randomized blocks in a 4 × 2 factorial scheme (2, 5, 8, and 10 dS m-1, with and without mycorrhizae) with eight repetitions to verify the development and mycorrhizal dependency (MD) of the seedlings previously inoculated, in salinized environment. The three species of AMF are associated with J. curcas both alone and together. Mycorrhizal dependency increased with salinity, indicating that J. curcas is a facultative species. The pre-colonized seedlings with AMF are an alternative to the establishment of J. curcas in salinized soils.

Abstract Drought is a major factor in decreased sugarcane productivity because of the resulting morphophysiological effects that it causes. Gene expression studies that have examined the influence of water stress in sugarcane have yielded divergent results, indicating the absence of a fixed pattern of changes in gene expression. In this work, we investigated the expression profiles of 12 genes in the leaves of a drought-tolerant genotype (RB72910) of sugarcane and compared the results with those of other studies. The genotype was subjected to 80–100% water availability (control condition) and 0–20% water availability (simulated drought). To analyze the physiological status, the SPAD index, Fv/Fm ratio, net photosynthesis (A), stomatal conductance (gs) and stomatal transpiration (E) were measured. Total RNA was extracted from leaves and the expression of SAMDC, ZmPIP2-1 protein, ZmTIP4-2 protein, WIP protein, LTP protein, histone H3, DNAj, ferredoxin I, β-tubulin, photosystem I, gene 1 and gene 2 was analyzed by quantitative real-time PCR (RT-PCR). Important differences in the expression profiles of these genes were observed when compared with other genotypes, suggesting that complex defense mechanisms are activated in response to water stress. However, there was no recognizable pattern for the changes in expression of the different proteins associated with tolerance to drought stress.

Sementes de oito genótipos de milho (BR3123, BR5004, BR5011, BR5026, BR5033, CMS50, D766 e ICI8447) foram semeadas em vermiculita e, após a germinação, transplantadas para vasos contendo solução nutritiva ou solução nutritiva com 100 mmol.L-1 de NaCl, em casa de vegetação. Durante o período experimental avaliaram-se, em plantas de todos os genótipos, sob condições de controle e estresse salino, os seguintes parâmetros: crescimento (matéria seca, relação de matéria seca parte aérea/raiz, área foliar, taxa de crescimento relativo e taxa de assimilação líquida), temperatura foliar, condutância estomática, transpiração, potencial hídrico antemanhã e teores de sódio, potássio, aminoácidos solúveis e carboidratos solúveis. O estresse salino reduziu o crescimento das plantas de todos os genótipos, sendo o BR5033 e o BR5011 caracterizados como tolerante e sensível ao estresse salino respectivamente. A resposta estomática do genótipo tolerante não foi influenciada pela salinidade. Entre os parâmetros estudados, a relação de matéria seca parte aérea/raiz e os teores de sódio e de solutos orgânicos nas folhas não mostraram relação com a tolerância à salinidade, isto é, não foram considerados bons marcadores morfo-fisiológicos para a tolerância à salinidade em milho. Em contraste, os teores de sódio e de solutos orgânicos nas raízes mostraram desempenhar um importante papel na aclimatação dos genótipos estudados ao estresse salino, sugerindo que eles poderiam ser usados como marcadores fisiológicos durante a seleção para tolerância à salinidade.

Seeds from eight different maize genotypes (BR3123, BR5004, BR5011, BR5026, BR5033, CMS50, D766 and ICI8447) were sown in vermiculite, and after germination they were transplanted into nutrient solution or nutrient solution containing 100 mmol.L-1 of NaCl and placed in a greenhouse. During the experimental period plant growth (dry matter, shoot to root dry mass ratio, leaf area, relative growth rate, and net assimilation rate), leaf temperature, stomatal conductance, transpiration, predawn water potential, sodium, potassium, soluble amino acids and soluble carbohydrate contents were determined in both control and salt stressed plants of all genotypes studied. Salt stress reduced plant growth of all genotypes but the genotypes BR5033 and BR5011 were characterized as the most salt-tolerant and salt-sensitive, respectively. Stomatal response of the salt-tolerant genotype was not affected by salinity. Among the studied parameters, shoot to root dry mass ratio, leaf sodium content and leaf soluble organic solute content showed no relation with salt tolerance, i.e., they could not be considered as good morpho-physiological markers for maize salt tolerance. In contrast, sodium and soluble organic solutes accumulation in the roots as a result of salt stress appeared to play an important role in the acclimation to salt stress of the maize genotypes studied, suggesting that they could be used as physiological markers during the screening for salt tolerance.

Plantas de feijão-de-corda (Vigna unguiculata (L.) Walp.) Pitiúba foram cultivadas em solução nutritiva e conservadas em casa de vegetação até o estádio de pré-floração, e foram submetidas a quatro tratamentos, a saber: solução nutritiva; solução nutritiva contendo NaCl a 75 mmol.L-1; solução nutritiva contendo NaCl a 75 mmol.L-1 e CaCl2 a 5 e a 10 mmol.L-1. O estresse salino inibiu fortemente o crescimento, provocou distúrbios no balanço hídrico das plantas e elevou o teor total de solutos inorgânicos nas diferentes partes das plantas, em vista, principalmente, do acúmulo de Na+ e Cl-. Além disso, aumentou o teor de carboidratos solúveis nas folhas e raízes, reduziu o teor de nitrogênio amino-solúvel, tanto nas extremidades das raízes como nas folhas trifolioladas mais jovens, e diminuiu os níveis de prolina nas extremidades das raízes. Embora a adição de CaCl2 ao ambiente radicular de plantas estressadas tenha provocado redução no teor de Na+, especialmente nas raízes, não minorou os efeitos do estresse nas relações hídricas e no crescimento das plantas. Os resultados obtidos, portanto, não dão suporte à hipótese de que o cálcio suplementar minoraria os efeitos inibitórios do estresse induzido por NaCl.

Pitiuba cowpea (Vigna unguiculata (L.) Walp.) plants were grown in nutrient solution and kept in a greenhouse up to pre-flowering stage. They were subjected to four different treatments: nutrient solution; nutrient solution containing 75 mmol.L-1 NaCl; nutrient solution containing 75 mmol.L-1 NaCl and 5 mmol.L-1 CaCl2; and nutrient solution containing 75 mmol.L-1 NaCl and 10 mmol.L-1 CaCl2. Salt stress strongly inhibited plant growth, caused a disturbance in plant-water balance, and increased the total content of inorganic solutes in the different plant parts, due mainly to accumulation of Na+ and Cl-. It also increased leaf and root soluble carbohydrates, reduced soluble amino nitrogen both in root tips and in the youngest trifoliate leaves, and reduced proline levels in root tips. Although the addition of CaCl2 to the root environment of salt stressed plants caused a reduction in Na+ content, specially in roots, it did not ameliorate the salt stress effects on plant-water relations and growth. Therefore, the results obtained do not support the hypothesis that supplemental calcium would ameliorate the inhibitory effects of NaCl-stress.