NaCl胁迫对甘薯某些生理性状的影响

Effects of NaCl Stress on Some Physiological Characters in Sweet Potato

应用水培法研究了NaCl胁迫对甘薯不同耐盐性品种的生理影响。结果表明,叶片细胞质膜透性、Na^+含量和游离脯氨酸积累均随NaCl浓度提高而显著提高,叶片含水量、K^+含量、K/Na比及叶绿素含量与之相反。在NaCl逆境下,耐盐性强的品种质膜透性及Na^+含量的增加幅度,K^+含量、叶片含水率及叶绿素含量的下降幅度均显著小于耐盐性差的品种;而脯氨酸的积累速度前者显著高于后者。质膜透性与Na^+含量呈极显著正相关,但二者均与叶片含水量、幼苗存活率、K/Na比以及叶绿素含量有极显著相关关系。因此,Na^+的积累及次生水分胁迫是导致膜伤害的主要原因,质膜透性可以作为甘薯耐盐性生理参数之一。

The effects of salinity on physiological changes were studied with five sweet potato varieties cultured in solution containing 0. 0% , 0. 4% and 0. 8% NaCl for 12 days. It was observed that plasmalemma permeability (PP), Na+ content and proline accumulation in leaves increased markedly with the increase in NaCl concentration, but the water content, K+ content , K/Na ratio and chlorophyll content decreased. Both the increases of PP and Na+ content and the decreases of chlorophyll, K+ and water content in leaves of high salt-tolerant varieties (HSTV) were much less than those of low salt-tolerant varieties (LSTV) at higher NaCl concentration. It was also found that proline accumulated sharply with the increase of NaCl concentration in the HSTV and slowly in the LSTV. Under NaCl stress condition, a highly significant (P<0. 01) positive correlation between PP and Na+ content in leaves was found. PP as well as Na+ content had significant negative correlations with the water content of leaves, survival percentage of cuttings, K/Na ratio and chlorophyll content of leaves, while the chlorophyll and water contents were significantly correlated with K/Na ratio. Thus the surplus accumulation of Na+ in internal body and the secondary water stress induced by NaCl stress are the main causes of salt injury, and PP may be considered as one of the physiological indexes for salt tolerance of sweet potato.