Chlorophyll a fluorescence of NO3-FED vs N2-fixing soybean grown under two water treatments

摘要: Abstract Diurnal courses of chlorophyll a fluorescence horizontally restrained and heliotropic leaves soybean plants (Glycine max (L.) Merr., cv. Cumberland), inoculated with N2-fixing Bradyrhizobium species grown under conditions high (HW) low (LW) water availability supplemental application 15 mM (NO3-fed) or 0.2 (N2-fixing) nitrate, were measured non-modulated fluorimeter for 3 consecutive days. Earlier studies have shown increased paraheliotropism in water-stressed nitrogen-grown plants. Since results lower irradiances, we hypothesized that midday quenching would be reduced oriented compared to horizontal leaves. A depression the ratio variable maximum (Fv/Fm) was all treatments. Of same nitrogen treatments, had greater reduction Fv/Fm orienting Within source, LW higher leaf angles less during periods relative those HW In contrast, Horizontally NO3-fed/LW plants, N2-fixing/HW N2-fixing/LW progressive decline early morning Fv/Fm. After 2 days being held horizontal, significantly than The minimum (F0) NO3-fed/LW, N2-fixing/HW, after horizontal. supported our initial hypothesis, indicated orientation light, temperature may result cumulative damaging effects upon metabolism soybean.