NaCl和NaHCO3胁迫下马蔺生长与光合特性的反应

RESPONSE OF IRIS LACTEA VAR.CHINENSIS TO NaCl AND NaHCO_3 STRESS IN GROWTH AND PHOTOSYNTHESIS

采用室内水培实验,以马蔺(Iris lactea Pall.var.chinensis(Fisch.)Koidz.)为研究对象,探讨盐(NaCl)、碱(NaHCO3)胁迫对植株生长、水分状况、质膜透性、叶片叶绿素含量和光合特性的影响,初步比较盐碱胁迫效应的差异。结果表明,在相同Na+浓度下,NaHCO3胁迫组对马蔺生长的抑制、细胞质膜透性的破坏以及叶绿素含量的减少程度均明显大于NaCl胁迫组,这可能是因为碱性盐胁迫下特有的高盐和高pH的共同作用。同时,盐碱胁迫对茎叶生长的抑制作用大于根系,对鲜重的影响大于干重。随着胁迫浓度的增加和胁迫时间的延长,马蔺叶片叶绿素含量显著降低。同时,叶片的电解质外渗率与植株含水量呈显著负相关。碱性盐胁迫下马蔺光合速率下降主要受非气孔限制,而中性盐胁迫下既有气孔限制,又有非气孔限制。

A hydroponical culture experiment of Iris lactea was conducted to explore responses of the plants to NaCl and NaHCO3 stress （0, 70, 210, 350 mmol L^-1） for 10 days in plant growth, water status, cell membrane permeability, chlorophyll content and photosynthetic characteristics. Results indicate that Treatments NaHCO3 were much higher than Treatments NaCl, the same in Na^＋ concentration, in effect inhabiting growth, decreasing water content, damaging cell membrane permeability and reducing chlorophyll content, which may probably be attributed to the combinative effect of high pH and high salinity in the former. Meanwhile, under alkali-saline stress, plant shoots were affected more than roots, and plant fresh biomass decreased more than dry biomass. Plant chlorophyll content decreased with increasing stress concentration and duration of the stress. Plant electrolyte leakage was negatively correlated to water content in leaves. Non-stomatal restriction was the main cause for reduced plant photosynthetic rate under NaHCO3 stress, while under NaCl stress, both stomatal restriction and non-stomatal restriction occurred.