盐胁迫对扁桃光合特性和叶绿体超微结构的影响

温室条件下,分别用浓度为150、300、350 mmol/L的NaCl和Na2SO4处理‘石头扁桃’和‘桃扁桃’实生苗植株,处理10 d后分别测定其叶片叶绿素含量、净光合速率、气孔导度、细胞间隙CO2浓度,并观察叶绿体超微结构的变化。研究发现:(1)盐胁迫下,‘石头扁桃’和‘桃扁桃’chl a、chl b均在低浓度盐区含量最高,而在高浓度盐区含量最低,Na2SO4处理区chl a、chl b含量均低于NaCl处理区;(2)‘石头扁桃’和‘桃扁桃’叶片净光合速率随盐浓度的增加而下降,‘石头扁桃’下降的幅度较大;(3)‘桃扁桃’叶片细胞间隙CO2浓度随盐浓度的增加而升高,但‘石头扁桃’叶片细胞间隙的CO2浓度变化没有稳定的规律;(4)2个品种的叶片气孔导度均随盐浓度的增加而降低;(5)盐胁迫后,叶绿体基粒、基质片层扭曲,类囊体肿胀;随盐浓度的增加,形变加剧,叶绿体由椭圆形肿胀成圆形,叶绿体膜解体,且‘石头扁桃’叶绿体对盐胁迫比较敏感。综合分析发现,2种盐胁迫对植物造成伤害的机理不同,‘石头扁桃’的耐盐能力较差。

Effects of Salt Stress on Photosynthetic Characters and Chloroplast Ultra-structure of Almond

150,300 and 350 mmol/L NaCl and Na_2SO_4 were used to treat the seed-originated seedlings of Amygdalus communis L.and A.communis var.persiooides in greenhouse.Then the chlorophyll contents,net photosynthetic rates and stomatal conductance and intercellular CO_2 concentrations in their leaves were determined and the ultra-structures of the leaves were observed.It was shown that(1) both Amygdalus communis L.and A.communis var.persiooides presented the highest chl a and chl b contents at low concentrations of the salts and the lowest chl a and chl b contents at higher concentrations of the salts,and the chlorophyll contents with Na_2SO_4 were lower than those with NaCl;(2) The net photosynthetic rates of Amygdalus communis L.and A.communis var.persiooides declined with increased salt concentration and the decrement in net photosynthetic rate was larger in Amygdalus communis L.;(3) The intercellular CO_2 concentration of A.communis var.persiooides increased with increased salt concentrations and the variation did not appeared regular;(4) The leaf stomatal conductance of the two declined with increased salt concentrations;(5) The salt stresses resulted in the chloroplast grana and stroma distorted and the choloroplast thylakoids swelling and the effects become intensified with increased salt concentrations,the chloroplasts swelling from elliptical shape to round shape and the chloroplast membrane disintegrating,and the chloroplasts of Amygdalus communis L.were more sensitive to the salt stresses.These results indicated that two salt stresses had different action mechanisms to damage the plants.A.communis var.persiooides was more tolerant to the salt stresses than Amygdalus communis L.