不同含氮化合物对NaCl胁迫下紫花苜蓿种子萌发特性的影响

探讨含氮化合物对NaCl胁迫下紫花苜蓿种子萌发及可恢复性的影响。试验共包括6种含氮化合物，各设8种浓度，测定发芽率指标。结果表明：各含氮化合物处理均未表现出缓解250 mmol/L NaCl抑制紫花苜蓿种子萌发的能力。胁迫部分缓解后，低浓度(0.625~10 mmol/L)处理萌发恢复较高，接近或超出对照水平，表明盐分和含氮化合物（氮肥）在一定程度上可以共存。高浓度(20~80 mmol/L)处理则出现2类情形：KNO₃、NaNO₃、(NH₄)₂HPO₄处理恢复萌发低，80 mmol/L处理几乎没有萌发；而NH₄Cl、NH₄NO₃、NH₄H₂PO₄均有较高的恢复萌发。结果显示盐胁迫效应与pH关系密切，盐碱地中改善紫花苜蓿生产时土壤碱性是一个值得优先考虑的限制因素。

Effects of Various Nitrogenous Compounds on Seed Germination of Medicago sativa L. under NaCl Stress

The present study explored the effect of nitrogenous compounds on seed germination and recovery of Medicago sativa L. under NaCl Stress. Six nitrogenous compounds were applied, each at eight concentrations. Seed germination percentage was determined. The result indicated that none of the nitrogenous compounds could alleviate the inhibitory effect of 250 mmol/L NaCl on seed germination of M. sativa. When salt stress was relieved, Treatments at lower concentrations (0.625-10 mmol/L) showed higher recovery germination, near or above the control level, suggesting the possibility of nitrogenous compounds (nitrogen fertilizers) coexisting with NaCl. Treatments at higher concentrations (20-80 mmol /L) divided into two distinct groups: KNO3, NaNO3 and (NH4) 2 HPO4 treatments had lower recovery germination, especially little recovery for 80 mmol/L treatments, whereas NH4Cl, NH4NO3 and NH4H2PO4 had higher recovery germination. These results implied that stress effect of salt is closely associated with pH, and alkaline is a priority for improving crop production in saline-alkali soil.