外源NO对NaCl胁迫下玉米幼苗生长和渗透调节能力的影响

采用水培法,研究了50、100、200μmol·L~(-1)外源一氧化氮(NO)供体硝普钠(SNP)对盐胁迫下玉米幼苗生长和渗透调节能力的影响。结果表明,外施NO可明显缓解Na Cl胁迫对玉米幼苗生长的抑制作用,与不施SNP的处理相比,100μmol·L~(-1)SNP处理全株干重的增加幅度达到19%。外施NO降低盐胁迫下玉米幼苗叶片及根系中可溶性糖和可溶性蛋白的含量,其中叶片中可溶性糖和可溶性蛋白分别降低19.9%和7.9%,根系中可溶性糖和可溶性蛋白含量分别降低9.6%和9%。外源一氧化氮(NO)使盐胁迫下玉米幼苗根系、生长叶和成熟叶叶鞘的Na~+含量分别降低38.4%、5.1%和17.2%;同时,增加根系和成熟叶叶鞘中K~+、Ca~(2+)、Mg~(2+)含量,降低玉米幼苗各器官内的Na~+/K~+、Na~+/Ca~(2+)比值,维持盐胁迫下玉米幼苗中的离子平衡,但对成熟叶片中离子含量的影响不大。研究认为,外源NO可维持盐胁迫下玉米幼苗的碳氮代谢平衡,改善玉米幼苗离子的吸收与分配,缓解Na Cl胁迫对玉米幼苗带来的伤害,其中以100μmol·L~(-1)的SNP处理效果最明显。

Effects of exogenous nitric oxide on growth and osmoregulatory capability of maize (Zea mays L.) seedlings under salt stress

A water culturing method was adopted to study the effects on the growth and osmoregulatory capability of maize seedling under NaCl stress and exogenous nitric oxide (NO ) donor sodium nitroprusside (SNP ) that was applied with three levels of treatments including 50 ,100μmol·L-1 and 200μmol·L-1 .The results indicated that the exogenous nitric oxide (NO ) could alleviate the inhibited growth induced by NaCl stress .Compared with the treatment without ap-plying SNP ,the total whole plant dry weight with 100 μmol·L-1 SNP was increased by 19% .The contents of soluble sugar and soluble protein in leaves of seedlings and roots were reduced by exogenous nitric oxide (NO ) ,being decreased by 19 .9% and 7 .9% in leaves and the 9 .6% and 9% in roots ,respectively .The content of Na+ in roots ,young blade and mature sheath of maize seedling under salt stress was apparently decreased by 38 .4% ,5 .1% and 17 .2% through the application of exogenous NO ,respectively .The contents of K+ ,Ca2+ ,and Mg2+ in root and mature sheath were rather increased .The ratios of Na+ /K+ and Na+ /Ca2+ in different organs of maize seedling were decreased ,and the ions balance in maize seedling under salt stress was maintained by exogenous NO .Exogenous NO caused subtle effect on the mature blade . It was concluded that exogenous nitric oxide (NO ) can keep the balance of carbon-nitrogen metabolism ,improve ions uptake and distribution in maize seedling under NaCl stress ,and alleviate the damage induced by NaCl stress .The concentration of SNP for the most apparent result was 100 μmol·L-1 .