The objective of this work was to compare the contents of polyamines (putrescine, spermidine and spermine), and total soluble phenols and flavonoids in parts of plants grown under either organic or conventional cropping, commonly discarded during food preparation. The contents of free polyamines, total phenols and total soluble flavonoids in peels (zucchini squash, banana, potato, eggplant, orange, lime, mango, passion fruit and radish), leaves (zucchini squash, broccoli, carrot, collard, cassava, radish and grape), stalks (broccoli, collard and spinach) and zucchini seeds were analysed. Most analysed vegetables presented higher contents of polyamines and total phenols under organic cropping, contrary to the results obtained for total flavonoids, possibly because of the cultural practices adopted.
Strobilurins are fungicides with beneficial physiological effects on crop yield due to promotion of net carbon assimilation, nitrate reductase enzyme activity, stress tolerance and hormonal balance. The carboxamides complement the action of the strobilurins when applied alternately or together. This study aimed to evaluate the effect of application of pyraclostrobin, azoxystrobin and boscalid on grafted and ungrafted Japanese cucumber (Cucumis sativus L.) in order to analyze the effects of these fungicides on plant physiology and increased fruit production. The experimental design was completely randomized in a 2 × 5 factorial scheme, with grafted and ungrafted cucumber plants and 5 fungicide treatments: control; azoxystrobin 60 g a.i ha −1 ; boscalid 50 g a.i ha −1 ; pyraclostrobin 50 g a.i ha −1 ; and boscalid 100 g a.i ha −1 + pyraclostrobin 50 g a.i ha −1 , applied 18 days after transplanting and then at intervals of seven days. The effect of the treatments was evaluated based on the average yield and fruit mass, in addition to observations of gas exchange, lipid peroxidation, and the activities of peroxidase, superoxide dismutase, catalase and nitrate reductase. Based on the results obtained, it was concluded that the fungicide treatments resulted in different responses between the grafted and ungrafted plants. The physiological benefits were more evident in the grafted plants treated with pyraclostrobin or boscalid alone, and these benefits manifested in terms of fruit production and increased the activity of the antioxidative system, thereby reducing stress. The higher productivity probably occurred due to the better physiological performance of these plants, mainly at the beginning of development, presenting greater activity of the enzyme nitrate reductase, in addition to the higher net CO 2 assimilation and carboxylation efficiency.
ResumoO trabalho objetivou verifi car o efeito de reguladores no crescimento de plantas de soja (Glycine max (L.) Merrill cv. BRS-184) e conteúdo de clorofi la. Em experimento instalado em casa-de-vegetação, plantas de soja (Glycine max (L.) Merrill cv. BRS-184) foram cultivadas em vasos de 10L, com terra da camada arável corrigida e adubada conforme a análise do solo. , os quais foram aplicados três vezes a intervalos de 30 dias e realizadas seis avaliações a intervalos de 13 dias. Os resultados revelaram que a maior produção de massa seca total ocorreu com a aplicação de IBA, Stimulate e cloreto de mepiquat. A área foliar foi inferior à testemunha na maioria dos tratamentos; o teor de clorofi la e a taxa de crescimento foram pouco infl uenciados pelos tratamentos. O tratamento com citocinina isolada ou associada a outros reguladores manteve por mais tempo o teor de clorofi la. A TCR e a TAL foram reduzidas a partir dos 99 dias após a semeadura com aplicação de cloreto de mepiquat.
Unitermos: Glycine max, retardantes de crescimento, auxina, citocinina
AbstractGrowth analysis of soybean plants treated with plant growth regulators. This work aimed to verify the effect of plant growth regulators on soybean plant growth and chlorophyll content. In an experiment carried out in a greenhouse, soybean plants were cultivated (Glycine max (L.) Merrill cv. BRS-184) in 10-liter pots containing soil from the arable layer, corrected and fertilized according to the soil analysis. The treatments used were: control; GA 3 100mg.L . Treatments were applied three times at 30-day intervals. Six samplings were taken at 13-day intervals. The results indicated that the highest total dry weight value resulted from the application of IBA and Stimulate, and that the application of mepiquat chloride in association with IBA and BAP reduced total dry matter production. The leaf area was smaller than the control in most treatments. The chlorophyll content and growth rate were slightly infl uenced by the treatments. The cytokinin treatment alone or in association with other plant growth regulators retained Biotemas, 21 (3): 53-63, setembro de 2008
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