水杨酸和茉莉酸甲酯对丹参幼苗叶片显微结构、光合及非结构糖积累的影响

研究了水杨酸(SA)和茉莉酸甲酯(MeJA)处理对丹参(Salvia miltiorrhiza Bunge)幼苗叶片显微结构、叶片光合能力及幼苗中非结构糖积累的影响.结果显示:SA处理增加了丹参幼苗叶片气孔密度；叶肉细胞排列紧密、体积减小,叶肉细胞内叶绿体数目减少,但叶绿体体积增大,叶绿体基粒片层结构的数目增加；叶片中叶绿素a、b含量、叶气孔导度、蒸腾速率以及净光合速率均增加；同时,幼苗根中和叶片中酸性转化酶活性降低,幼苗地上部分蔗糖含量及可溶性糖总量显著高于对照.MeJA处理减少了叶片气孔密度,气孔发育畸形；叶肉细胞间隙增大,栅栏细胞层数减少,叶肉细胞内叶绿体数目减少,叶绿体体积减小,叶绿体基粒片层结构被破坏；叶片中叶绿素a及类胡萝卜素含量、叶片的净光合速率低于对照,叶气孔导度、蒸腾速率增强；同时,幼苗根中及叶中酸性转化酶活性增加,幼苗根中蔗糖含量及可溶性糖总量显著低于对照.可见,SA处理能促进植物叶片显微结构发育,增强叶片光合能力,抑制蔗糖降解并促进蔗糖积累；而MeJA处理则破坏了植物叶片显微结构,降低了叶片光合能力,促进了蔗糖降解并减少蔗糖积累.

Influence of Salicylic Acid and Methyl Jasmonate on Leaf Microstructure, Leaf Photosynthesis,and Non-structure Sugar Accumulation of Salvia miltiorrhiza Bunge Seedlings

We investigated the effects of salicylic acid （SA） and methyl jasmonate （MeJA） fo- liar applications on photosynthesis and accumulation of non-structure sugar of Salvia miltiorrhiza Bunge seedlings. Results showed that SA treatment was favorable in developing leaf micro- structure and increased leaf stomata density. Intercellular space in the mesophyll tissue,size of mesophyll cell,and number of chloroplast per mesophyll cell were also reduced,but the size of chloroplast and number of granum in the chloroplast were markedly increased. Corresponding- ly,contents of chlorophyll a and b in the leaves,net photosynthetic rate of the leaves,and con- tents of sucrose and soluble sugar in shoots of the SA-treated seedling were together signifi- cantly increased following decreased activity of acid invertase in both shoots and roots. The MeJA application to the seedlings resulted in contrary effects in decreasing density of leaf sto- mata,incurring a number of abnormal stomata, decreasing layer of palisade cell and increasing intercellular space in mesophyll tissue, while number and size of chloroplast was notablyreduced and granum in the chloroplast was destroyed. The MeJA treatment also decreased contents of chlorophyll a and carotenoid in leaves but significantly increased activity of acid in- vertase in both shoots and roots of the seedlings ; as a consequence leaf net photosynthetic rate,contents of sucrose and total amount of soluble sugar in roots of the seedlings were de- creased. In conclusion,the SA application to S. miltiorrhiza seedling accelerated sucrose ac- cumulation by promoting the development of leaf microstructure to accelerate photosynthesis and inhibiting sucrose hydrolysis,while MeJA application to the seedlings decreased sucrose accumulation by damaging leaf microstructure to impair photosynthesis and accelerating su- crose hydrolysis.