Efeitos do estresse hídrico prolongado sobre a produção de biomassa, crescimento e a nodulação em plantas de soja

Effects of prolonged drought on biomass production, growth and nodulation in soybean
M. E. F. Pereira (1), T.A. Souza (2)
(1,2)

Viçosa Federal University, Viçosa, Brasil ([e-mail]),

(2)

([e-mail])

Abstract: soybean producing regions with lower rainfall of 2.5 mm at the beginning of culture can induce water stress at various growth stages of soybean. The magnitude of adverse done depends on the intensity and duration of stress. The tolerance of soybean to short periods of water deficit is attributed to root development and the relatively long period of flowering.
Accordingly, this study aimed to evaluate the effects of prolonged drought periods during the vegetative and reproductive growth of soybean [Glycine max (L.) Merrill] cultivars MGBR46 and Monarca cycle medium late. The experiment was conducted in protected and nonlimiting conditions of light, temperature and nutrition at research areas of salt stress DEA /
UFV. The plants were grown in pots containing six liters of soil which were irrigated daily to keep them in 80 and 40% of field capacity for plants without and with water stress, respectively, between 21 and 100 days of the cycle. The critical limit of water stress was determined in 33% of field capacity with the manifestation of mild wilting leaves. We measured the evolution of biomass production, nodulation, biomass relative shoot / root, and the average weight of pods + immature grains, a similar time intervals. The results showed that water stress still presents significant manifestations between 21 and 42 days after water restriction (DAWR), demonstrations intensify with duration. Evaluations of characteristics in
R7 were found reductions in dry mass of leaves, stems and roots in the order of 4.6, 6.0 and
10 times, respectively, in plants under water stress versus irrigated. The reductions were significant between 35 and 42 DAWR in dried pasta leaves, stems and roots. Early, were affected the