[Effect of exogenous α-naphthaleneacetic acid on carbon metabolism of soybean under drought stress at flowering stage]. / 外源α-è˜ä¹™é ¸å¯¹èŠ±æœŸå¹²æ—±å¤§è±†ç¢³ä»£è°¢çš„å½±å“.

With pot experiment, two soybean (Glycine max) varieties, Jindou 21 (drought-tole-rant) and Xudou 22 (drought-sensitive), were used to examine the effects of α-naphthaleneacetic acid (NAA) on carbon metabolism of soybean under drought stress at flowering stage. The results showed that under drought stress, compared to Xudou 22, Jindou 21 had smaller decrease in net photosynthetic rate (Pn), smaller increase in photorespiration rate (Pr) and soluble sugar content of leaves, while a greater increase in the activities of sucrose phosphate synthase (SPS) and sucrose synthetase (SS) (synthesis) of leaves and sucrose content of roots. NAA treatment increased Pn and decreased Pr under drought stress, and thus obviously alleviated the growth inhibition of drought stress on plants. NAA treatment reduced the activities of starch-degrading enzymes, acid invertase (AI) and SS (cleavage), thereby inhibited the accumulation of soluble sugar induced by drought stress. In addition, NAA treatment increased SPS and SS (synthesis) activities of leaves, sucrose content of roots and shoot-root ratio, indicating that NAA treatment improved the transportation of sucrose from leaf blade to root under drought stress. In conclusion, exogenous NAA could enhance drought tolerance in soybean by regulating carbon metabolism.

[Effects of exogenous α-naphthaleneacetic aid on the antioxidation system in soybean leaves subjected to long-term drought stress during flowering].

Two different drought tolerance soybean ( Glycine max) varieties (Nannong 99-6 and Kefeng 1) were used to study the effects of α-naphthaleneacetic acid (NAA) on the antioxidation system under long-term drought stress after flowering with pot experiment, which lasted for 110 days at Pailou Experiment Station, Nanjing Agricultural University, in 2012. The results showed that long-term stress decreased the shoot dry mass significantly, however, increased the level of reactive oxygen species (ROS) and malondialdehyde (MDA) content. It also obviously increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) , ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), glutathione reductase (GR) and glutathione peroxidase (GPX). The contents of ascorbic acid (AsA) and glutathione (GSH), and the ratios of AsA/DHA (dehydroascorbic acid) and GSH/GSSG (L-glutathione oxidized) were obviously enhanced. Kefeng 1 showed a higher antioxidation ability than Nannong 99-6, and could consequently maintain lower ROS and MDA levels. NAA distinctly enhanced the activities of APX, POD, CAT, MDHAR, GPX, and ratios of AsA/DHA and GSH/GSSG, while decreased the levels of ROS and MDA. The AsA content and dehydroascorbate reductase (DHAR) activity were significantly increased in Kefeng 1.