RESUMEN
Nitrate (NO3 - ) nutrition is known to mitigate the damages caused by individual stresses of waterlogging and salinity. Here, we investigated the role of NO3 - in soybean plants exposed to these stresses in combination. Nodulated soybean cultivated under greenhouse conditions and daily fertilised with a nutrient solution without nitrogen were subjected to the following treatments: Water, NO3 - , NaCl, and NaCl+NO3 - . Then, plants were exposed to waterlogging (6days) and drainage (2days). Compared to plants exposed to isolated stress, the saline waterlogging resulted in higher concentrations of H2 O2 , O2 Ë- , and lipid peroxidation at the whole-plant level, mainly during drainage. Furthermore, saline waterlogging increased fermentation and the concentrations of Na+ and K+ in roots and leaves both during waterlogging and drainage. NO3 - supplementation led to augments in NO3 - and NO levels, and stimulated nitrate reductase activity in both organs. In addition, NO3 - nutrition alleviated oxidative stress and fermentation besides increasing the K+ /Na+ ratio in plants exposed to saline waterlogging. In conclusion, NO3 - supplementation is a useful strategy to help soybean plants overcome saline waterlogging stress. These findings are of high relevance for agriculture as soybean is an important commodity and has been cultivated in areas prone to saline waterlogging.
Asunto(s)
Nitratos , Nitrógeno , Cloruro de Sodio , Glycine max , Fermentación , Solución Salina , Estrés OxidativoRESUMEN
In this study, we tested whether waterlogging priming at the vegetative stage would mitigate a subsequent waterlogging event at the reproductive stage in soybean [Glycine max (L.) Merr.]. Plants (V3 stage) were subjected to priming for 7days and then exposed to waterlogging stress for 5days (R2 stage) with non-primed plants. Roots and leaves were sampled on the fifth day of waterlogging and the second and fifth days of reoxygenation. Overall, priming decreased the H2 O2 concentration and lipid peroxidation in roots and leaves during waterlogging and reoxygenation. Priming also decreased the activity of antioxidative enzymes in roots and leaves and increased the foliar concentration of phenols and photosynthetic pigments. Additionally, priming decreased fermentation and alanine aminotransferase activity during waterlogging and reoxygenation. Finally, priming increased the concentration of amino acids, sucrose, and total soluble sugars in roots and leaves during waterlogging and reoxygenation. Thus, primed plants were higher and more productive than non-primed plants. Our study shows that priming alleviates oxidative stress, fermentation, and carbohydrate consumption in parallel to increase the yield of soybean plants exposed to waterlogging and reoxygenation.
Asunto(s)
Fabaceae , Glycine max , Glycine max/metabolismo , Agua/metabolismo , Hojas de la Planta/metabolismo , Fabaceae/metabolismo , Carbohidratos , Estrés OxidativoRESUMEN
Resistance to the root-knot nematodes Meloidogyne spp. would be a valuable attribute of lettuce Lactuca sativa L. cultivars grown in tropical regions. The looseleaf lettuce 'Grand Rapids' is resistant to both M. incognita and M. javanica. Resistance to M. incognita has a high heritability, under the control of a single gene locus, in which the 'Grand Rapids' allele, responsible for resistance (Me), has predominantly additive gene action, and has incomplete penetrance and variable expressivity. We studied the inheritance of the resistance of 'Grand Rapids' (P(2)) to M. javanica in a cross with a standard nematode-susceptible cultivar Regina-71 (P(1)). F(1)(Regina-71 x Grand Rapids) and F(2) seed were obtained, and the F(2) inoculated, along with the parental cultivars, with a known isolate of M. javanica to evaluate nematode resistance. A high broad sense heritability estimate (0.798) was obtained for gall indices. Class distributions of gall indices for generations P(1), P(2), and F(2) were in agreement with theoretical distributions based on a monogenic inheritance model for the range of assumed degrees of dominance between approximately -0.20 and 0.20. M. javanica resistance appears to be under control of a single gene locus, with predominantly additive gene action. Whether or not the Grand Rapids allele imparting resistance to M. javanica is the same Me allele imparting resistance to M. incognita remains to be determined.