喷施外源激素对‘玉露香’梨叶片表皮蜡质组分、结构及渗透性的影响

[目的]本文旨在揭示外源激素氨基乙酰丙酸（ALA）、茉莉酸甲酯（MeJA）和水杨酸（SA）对植物叶片表皮蜡质合成的影响。[方法]以‘玉露香’梨为试材，叶片喷施不同浓度的ALA、MeJA、SA及MeJA+SA，研究其对叶片表皮蜡质含量、组分、结构以及渗透性的影响。[结果]喷施外源激素后，与对照相比，ALA和MeJA处理的叶片蜡质总量均增加，SA处理的差异不大，而MeJA+SA处理的蜡质总量减少，且不同处理7 d时蜡质总量均高于14 d。喷施不同外源激素后蜡质各组分也发生明显的变化。与对照相比，ALA处理叶片酯类含量在7 d时减少而在14 d时增加，伯醇含量在2个时期均增加。MeJA处理叶片烷烃含量在7 d时增加而在14 d时减少。SA处理7 d时叶片蜡质组分影响较小，14 d时伯醇和酯类含量均增加。MeJA+SA处理叶片酯类含量在7 d时减少，而烷烃、脂肪酸含量在14 d时减少。其中，C27、C30、C31烷烃，C26、C28、C30伯醇和C16、C18脂肪酸是被激素诱导的主要蜡质成分。‘玉露香’梨叶片表面为薄膜状蜡质层，表面较平滑，有褶皱，无裂纹。ALA以及MeJA+SA处理后蜡质层褶皱减少，而MeJA处理后叶片表面褶皱明显增多、变密，且出现较多蜡质晶体。SA处理对蜡质结构影响较小。此外，ALA、MeJA和SA处理能够减缓叶片的水分散失，而MeJA+SA处理加快叶片的水分散失。[结论]本研究表明蜡质层的沉积与结构变化可降低渗透性，减缓叶片的水分散失。SA、MeJA和ALA处理可能通过增加C27以上碳链长度的烷烃含量，减少蜡质的失水率。
[Objectives]The aim of this research is to reveal the regulation effect of aminolevulinic acid(ALA),methyl jasmonate(MeJA)and salicylic acid(SA)to the cuticular wax composition and deposition.[Methods]In this study,the leaves of ‘Yuluxiang’ pear were used as materials,treated with different concentration of ALA,MeJA,SA and combination of MeJA and SA,and their effects on the cuticular wax content,composition,structure and permeability were studied.[Results]The total wax content increased after ALA and MeJA treatments,but no obvious change was detected after SA treatment. On the contrast,the total wax content decreased after the combination treatments of MeJA and SA. Moreover,the total wax content highly improved at 7 days than 14 days after all the different treatments. The wax component significantly changed in ‘Yuluxiang’ pear leaf after exterior hormones treatment. The content of esters decreased at 7 days,whereas increased at 14 days,and the content of primary alcohols both increased at 7 and 14 days after ALA treatment. The content of alkane increased at 7 days,whereas decreased at 14 days after MeJA treatment. SA treatment had a little impact on wax component at 7 days,and the content of primary alcohols and esters decreased at 14 days. The esters content decreased after the combination treatments of MeJA and SA at 7 days,and the content of alkanes and fatty acids decreased at 14 days. C27,C30,C31 alkane,C26,C28,C30 primary alcohol and C16,C18 fatty acid compound were the main cuticular wax constituents induced by exterior hormones application. Scan electric microscope analysis indicted that cuticular wax layer on the leaf surface of ‘Yuluxiang’ pear was smooth and folding without visible wax crystals,shaped like typical smooth wax films. The folding structures of cuticular wax on leaf surface were reduced under ALA and combined of MeJA and SA treatments. MeJA application