苹果试管苗对盐碱胁迫的生理响应特性

Physiological Characteristics of Two Apple Plantlets in Response to Saline Alkali Stress

以长富2号和嘎啦试管苗为试验材料,采用液体培养法,将NaCl和NaHCO3溶液等体积混合,设置4个盐碱浓度(0、50、100、200mmol/L)进行胁迫处理,测定其生长量、膜透性、抗氧化酶活性及叶绿素含量等生理指标。结果表明,与未胁迫处理相比,盐碱胁迫下2个品种试管苗叶片中的脯氨酸、Na+大量积累;生长量受到抑制,根系活力和叶绿素含量均显著下降;膜透性显著升高。随着盐碱浓度的增大,2个品种试管苗的超氧化物歧化酶(SOD)均呈先降后升的趋势,50mmol/L为峰值;嘎啦的抗坏血酸过氧化物酶(APX)先上升后下降,而长富2号呈相反趋势,且盐浓度为200mmol/L时,2个品种试管苗均死亡。长富2号的生长量、根系活力、叶绿素含量均显著低于嘎啦,嘎啦的APX含量显著高于长富2号。表明嘎啦主要通过提高细胞的抗氧化能力而增加植株的抗逆性,从而更好地适应盐碱胁迫。

Changfu 2 and Gala were employed experimental materials and 4 different concentrations of mixed saline-alkali treatment(0,50,100,200 mmol/L)were simulated on the basis of NaCl and NaHCO3 were mixed in equal volume by using liquid culture method.The changes of mixed saline-alkali on growth,membrane permeability,antioxidant enzyme activity and chlorophyll content were measured.Compared with the no stress control,proline and Na+accumulated in the leaves of two plantlets under saline-alkali stress;the growth was inhibited,root activity and chlorophyll content decreased significantly;whereas the membrane permeability increased remarkcaly.With the increase of saline-alkali concentration,the superoxide dismutase(SOD)of both plantlets decreased first and then increased,with a peak value of 50 mmol/L,Gala ascorbic acid peroxidase(APX)increased first and then decreased,while Changfu 2 showed an opposite trend,and when the salt concentration was 200 mmol/L,both plantlets died.Meanwhile,the growth,root activity and chlorophyll content of Changfu 2 were significantly lower than those of Gala,while the APX content of Gala was markedly higher than that of Changfu 2.Therefore,Gala increases the stress resistance of plants mainly by improving the antioxidant capacity of cells,so as to better adapt to salt-alkali stress,which provides a theoretical basis for screening good varieties of salt-alkali resistance.