四种暖季型草坪植物的盐胁迫反应及其耐盐阈值

Salinity stress responses and tolerance thresholds in four warm-season turfgrasses

以百慕大‘Tifdwarf’、假俭草、海滨雀稗‘Salam’和结缕草4种暖季型草坪植物为材料,研究了不同盐(NaCl)浓度处理对草坪植物生长和生理的影响。结果表明,海滨雀稗耐盐性最好,海滨雀稗的目测质量、相对生长率、叶片相对含水量、叶绿素指数、光化学效率在600 mmol/L盐浓度处理36 d时分别下降了52.2%,76.2%,62.1%,59.4%和72.9%,相对电导率上升至71.5%,与其他3个草种相比,海滨雀稗各指标仍能维持较高的水平,膜伤害程度相对较小;结缕草耐盐性次之,600 mmol/L盐处理36 d时目测质量、相对生长率、叶片相对含水量、叶绿素指数、光化学效率分别下降了85.2%,85.3%,70.5%,73.9%和49.3%,相对电导率上升至81.8%,表现出较好的耐盐性;耐盐性表现很差的为百慕大和假俭草,在600 mmol/L盐浓度处理36 d时,2种草的各指标皆下降至0,膜伤害程度达到最大,草坪草已枯死。盐处理36 d时,将生长量与盐处理浓度建立回归方程,以生长量下降50%作为耐盐阈值的确定指标,求得4个草种的耐盐阈值分别为为:假俭草222.4 mmol/L,百慕大232.4 mmol/L,结缕草374.8 mmol/L和海滨雀稗474.0 mmol/L。

Four warm-season turfgrass species EBermudagrass ‘Tifdwarf’ （Cynodon dactylon × C. transadlensis）, Centipedegrass （Eremochloa ophiuroides）, Seashore Paspalum ‘Salam＇ （Paspalum vaginatum）, and Zoysiagrass （Zoysia matrella）] were grown in PVC pots under a series of NaCl concentrations to study the salinity stress responses of turfgrass growth and physiological parameters. Seashore Paspalum showed the best salinity tolerance. The visual quality, relative growth rate, relative water content, chlorophyll index, and Fv/ Fm decreased 52.2%, 76.2%, 62.1%, 59.4%, and 72.9%, respectively after 36 d at 600 mmol/L NaCl, but the electrolyte leakage increased to 71.5%. The ceil membrane damage in Seashore Paspalum was the lowest of the three species. Zoysiagrass also showed good salinity tolerance, with decreases in visual quality, relative growth rate, relative water content, chlorophyll index, and Fv/Fm of 85.2%, 85.3%, 70.5%, 73.9%, and 49.3%, respectively after 36 d at 600 mmol/L NaCl, and with an increase in electrolyte leakage of 81.8%. Bermudagrass and Centipedegrass showed the lowest salinity tolerance with treatment of 600 mmol/L NaCl and both species were dead after 36 d. The salinity tolerance thresholds of four turfgrass species were determined using linear regression of plant growth rate against NaCl concentration. After 36 d treatment plant growth rate was reduced to 50% of the control. The tolerance thresholds are Centipedegrass 222.4 mmol/L, Bermudagrass 232.4 mmol/L, Zoysiagrass 374.8 mmol/L, and Seashore paspalum 474.0 mmol/L.