外源茉莉酸对盐胁迫下玉米光合特性的影响

Effects of exogenous jasmonic acid on photosynthetic characteristics of maize under salt stress

玉米(Zea mays L.),为禾本科玉米属一年生单子叶植物,是全球种植范围最广、产量最高的谷类作物,居三大粮食之首.植物激素被认为在调节植物对逆境胁迫的响应中起关键作用,其中茉莉酸(JA)被认为可调节应激反应,影响植物生长和发育.为研究外源JA对盐胁迫下玉米光合特性的影响,本研究以玉米植株为实验材料,采用1/2 Hoagland液体培养基培养玉米植株,待植株生长到五叶期时,以50 mmol/L NaCl胁迫2 d,之后每24 h叶面喷施1 mmol/L JA,连续喷施2 d,探究在盐胁迫下外施JA对玉米植株的根系形态、光合特性及叶绿素荧光特性的影响.在盐胁迫下,施用外源JA时,玉米植株的P n增加了31.0%,G s增加了32.2%.ΦPSII和F v/F m显著提高.结果表明JA处理促进了盐胁迫条件下玉米植株根系生长发育,提高了光合系统的能力.外源JA可以减少盐胁迫引起的PSII反应中心的损伤,促进光化学电子的转移,保证碳同化反应的正常化.本研究确定了外源JA对玉米盐胁迫的缓解机理,为缓解玉米盐害提供理论和技术依据.

Zea mays L.is an annual monocotyledonous plant of the genus Cornaceae.It is the world s most widely planted cereal crop with the highest yield and ranks first among the three major foods.Plant hormones are play a key role in regulating plant responses to stress.Jasmonic acid is thought to regulate stress response and affect plant growth and development.In order to study the effect of exogenous JA on the photosynthetic characteristics of maize under salt stress,maize were used as experimental materials to culture maize plants in 1/2 Hoagland liquid medium.When the plants were grown to the five-leaf stage,they were stressed with 50 mmol/L NaCl for 2 d,then sprayed 1 mmol/L JA every 24 h,and sprayed continuously for 2 d.The root morphology,photosynthetic characteristics and chlorophyll fluorescence characteristics of maize were researched under salt stress.Under salt stress,when exogenous JA was applied,the P n of corn plants increased by 31.0%and G s increased by 32.2%.ΦPSII and F v/F m are significantly improved.The results showed that JA treatment promoted the growth and development of maize roots under salt stress and improved the ability of photosynthetic system.Exogenous JA can reduce the damage of PSII reaction center caused by salt stress,promote the transfer of photochemical electrons,and ensure the normalization of carbon assimilation reaction.This study determined the mechanism of exogenous JA on the salt stress of maize and provided theoretical and technical basis for alleviating corn salt damage.