NaCl胁迫对马齿苋离子吸收及荧光特性的影响

Effects of NaCl Stress on the Ion Distribution and Chlorophyll Fluorescence in Portulaca oleracea L.

以马齿苋为材料采用温室盆栽法,研究了NaCl胁迫处理对其生长发育、品质积累、离子分布和叶绿素荧光特性的影响。结果表明,马齿苋种子发芽率、幼苗的鲜质量和株高在25～50 mmol/L NaCl胁迫时比对照略有下降,但其随着NaCl浓度的继续增加均显著降低。0～75 mmol/L NaCl处理浓度可提高马齿苋幼苗维生素C含量。盐胁迫影响植物组织的离子分布,Na+浓度持续增加,K+、Ca2+和Mg2+浓度下降。NaCl胁迫下,马齿苋幼苗叶片的初始荧光(Fo)、最大荧光(Fm)、PSⅡ潜在光化学效率(Fv/Fo)和PSⅡ实际光化学效率(ФPSⅡ)均降低。但在0～50 mmol/LNaCl浓度下,各荧光参数与对照差异不显著。可见,NaCl胁迫下,马齿苋产生了光合作用的光抑制伤害。低浓度下,植株能够较多地将光能用于光化学反应,光抑制程度较低,保持了较高的净光合速率,最终明显减轻盐胁迫对植株生长的影响。

Pot experiments were carried out to study the effects of NaCl stress on the growth,quality,ion distribution and chlorophyll fluorescence in Portulaca oleracea L.Eight different concentrations of NaCl were applied：0,25,50,75,100,150,200,250 mmol/L.The results showed as follows：The germination rate,plant fresh weights and heights of seedlings had no difference with the control when the concentration of NaCl was 25-50 mmol/L,but decreased when the NaCl concentration was above 50 mmol/L.When the concentration of NaCl was 0-75 mmol/L,the Vc content of Portulaca oleracea L.increased.Increased treatment of NaCl induces increased of Na＋ and decreased of K＋,Mg2＋ and Ca2＋.Minimal fluorescence（Fo）,maximum fluorescence（Fm）,PSⅡ potential fluorescence efficiency（Fv/Fo） and PSⅡ actual fluorescence efficiency（ФPSⅡ） all decreased when stressed by NaCl.And at low concentrations NaCl（0-50 mmol/L） stress,the fluorescence parameters changed slightly.So Portulaca oleracea L.was injured by photo-inhibition on NaCl stress,and at low concentrations,plant applied more light energy to photochemical reaction to maintain a high net photosynthetic rate,the degree of photo-inhibition was lower,therefor,NaCl stress had little effect on growth.