四倍体刺槐的抗盐性

 以四倍体刺槐(Robinia pseudoacacia)为主要试验材料，以二倍体刺槐为对照材料，在两种盐胁迫下，对苗木的形态、生理生化、光合特性和解剖结构等指标的变化规律进行了研究。利用NaCl和Na₂SO₄盐溶液对两种刺槐进行盐处理，在30 d后每7 d处理1次，共处理4次，并在处理前和处理后每7 d进行各项指标的测定。结果发现：1)在盐胁迫下二倍体刺槐的植株生长受到强烈抑制，叶片含水量和叶绿素含量显著低于对照,有明显的盐害症状；对四倍体刺槐植株的生长影响较小,叶片含水量和叶绿素含量也与对照差异不显著，无盐害症状。2)四倍体刺槐经过盐处理后相对电导率和脯氨酸(Proline, Pro)含量虽然也稍有上升，但与对照相比未达到显著水平，而二倍体刺槐显著高于对照；同时作为保护酶系统的过氧化物酶(Peroxidase, POD)、超氧化物歧化酶(Superoxide dismutase, SOD)、过氧化氢酶(Catalase, CAT)在四倍体刺槐经盐胁迫后期也保持了较高的活性，从而提高了其抗盐性，而对盐敏感的二倍体刺槐3个保护酶活性均较低。 3)经盐胁迫后对四倍体刺槐光合特性影响不大，净光合速率（Net photosynthetic rate, P_n）和胞间CO₂浓度（Intercellular CO₂ concentration, C_i）均无显著变化，而二倍体刺槐P_n和C_i显著下降。4)经盐胁迫后四倍体刺槐在解剖结构上做出了积极的反应：叶肉栅栏组织拉长、排列更为紧密、 海绵组织变小、排列紧密。而二倍体刺槐出现了相反的现象。综合以上分析认为：四倍体刺槐具有较强的抗盐性。

SALT RESISTANCE OF TETRAPLOID ROBINIA PSEUDOACACLA

Aims Our objective was to compare tetraploid vs. diploid Robinia pseudoacacia for salt stress effects on their morphology, physiology, physiobiology, photosynthesis and anatomy. Methods We grew tetraploid and diploid R. pseudoacacia treated four times with two salts, NaCl and Na₂SO₄, and untreated diploid R. pseudoacacia as a control. After 30 days, we examined them every 7 days. Important findings The growth of diploid R. pseudoacacia was restrained, its water content and chlorophyll content had obvious differences to the control, and salt injury was eventually observed. The water content and chlorophyll content of tetraploid R. pseudoacacia had no obvious differences to the control, and salt injury was not observed. Relative REC （Relative conductivity）　and Pro (Proline) activity of tetraploid R. pseudoacacia increased slightly, but were not different from the control. Relative REC and Pro activity in treated diploid R. pseudoacacia were higher than the control. The protective systems of peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) retained higher activity at late periods in tetraploid R. pseudoacacia under salt stress, which contributed to salt tolerance, but they retained lower activity in treated diploid R. pseudoacacia. Photosynthesis in tetraploid R. pseudoacacia was not affected by salt stress, as net photosynthetic rate (P_n) and intercellular CO₂ concentration (C_i) were unchanged, but changes did occur in diploid R. pseudoacacia. The leaf anatomy of tetraploid R. pseudoacacia changed, e.g., palisade cells were longer and more densely packed and spongy mesophyll cells were more densely packed. Based on these findings, tetraploid R. pseudoacacia had stronger salt tolerance.