不同程度盐胁迫对大豆苗期生物量及生理指标的影响

Effects of Different Degree Salt Stress on Biomass and Physiological Indexes of Soybean Seedling

为研究大豆在不同程度盐胁迫下的耐盐规律,并探讨盐胁迫下影响植株生长的主要生理原因,以4份不同耐盐性大豆品种为供试材料,采用营养液水培法,用不同浓度NaCl溶液处理,测定苗期大豆植株生长指标、叶片SPAD、各部位Na^+、K^+、Cl^-含量并进行规律分析。结果表明:(1)植株地上部鲜重和干重及地下部鲜重随盐溶液浓度的升高先增大后减少,在200 mmol·L^-1高浓度盐胁迫下均显著低于对照,植株地下部干重在盐胁迫下变化未达显著水平。耐盐性品种在高浓度盐胁迫下植株生物积累量受抑制程度较低。高浓度盐胁迫显著降低了植株叶片SPAD,进而影响其光合作用,抑制植株生物量的积累。(2)植株根茎叶中Na^+和Cl^-含量随盐溶液浓度升高而增加,根中Na^+和Cl^-的积累较茎和叶对盐胁迫更敏感,耐盐性品种在盐胁迫下根中Cl^-积累较少,茎叶中Na+积累较多。植株根茎中K+含量随盐溶液浓度的升高而减少,叶片中的K^+含量在盐溶液处理下变化未达显著水平。(3)除耐盐品种晋大73外,其它品种在盐胁迫下植株茎叶中Na^+和Cl^-含量与植株生物量呈显著负相关,所有品种植株叶片中Na^+和Cl^-的含量与叶片SPAD呈显著负相关,表明盐害离子的积累是造成植株生物量减少、叶片失绿的重要原因。耐盐品种植株茎叶中Na^+和Cl^-含量与植株生物量相关性不显著,表明盐害离子对耐盐品种植株生物积累量影响不明显。

In order to study the trent of salt tolerance of soybean under different salt stress, and to explore the main physiological reasons that affecting plant growth under salt stress, we used the methods of nutrient hydroponic culture and different concentration of NaCl solution to determine the traits of four soybean varieties with different salt tolerance at seedling stage. The plant growth index, SPAD of leaves, Na+, K+ and Cl- content of each part were tested. Results showed that:(1) The fresh and dry weight of the aboveground part and the fresh weight of the underground part of the plant increased firstly and then decreased with the increasing of salt solution concentration and it was significantly lower than the control group under high concentration salt stress of 200 mmol·L^-1, but the dry weight of underground part of the plant did not change significantly under salt stress. The plant biomass of salt-tolerant varieties were inhibited to a lesser extent under high salt stress. High concentration salt stress significantly reduced the SPAD of plant leaves, thus affecting photosynthesis and inhibiting the accumulation of plant biomass.(2) The contents of Na^+ and Cl^- in roots, stems and leaves of plants increased with the increasing of salt solution concentration, and the accumulation of Na+ and Cl- in roots was more sensitive to salt stress than in stems and leaves, for salt tolerant varieties, the accumulation of Cl^- in roots was less and Na+ in stems and leaves was more under salt stress. The K^+ contents in roots and stems decreased with the increasing of salt solution concentration, while the K+ contents in leaves did not change significantly under salt solution treatment.(3)The contents of Na^+ and Cl^- in the stems and leaves of plants under salt stress was negatively correlated with the plant biomass in all varieties except the salt-tolerant variety Jinda 73, and the contents of Na^+ and Cl^- in leaves of all varieties were negatively correlated with the SPAD of leaves. This results showed that the accumulation of salt ions was an important reason for the decrease of plant biomass and leaf green loss. There was no significant correlation between the contents of Na^+ and Cl^- in the stems and leaves of salt-tolerant cultivars and the plant biomass, indicating that the effect of salt-damaged ions on the plant biomass of salt-tolerant cultivars was not significant.