‘黄冠’梨正常试管苗与玻璃化苗生理生化及超微结构的比较研究

Comparative Study on Physiological and Biochemical Characteristic and Ultra-structure in Normal and Hyperhydric Shoots in Vitro of ‘Huangguan’ Pear

以正常和玻璃化‘黄冠’梨试管苗为试材进行组培快繁、生理生化及组织结构比较研究。结果表明:玻璃化苗较正常苗增殖能力显著降低,增殖出的试管苗仍为玻璃化苗,并且玻璃化程度加重;干物质积累较正常苗低31.3%,淀粉含量低29.57%,而可溶性糖含量高13.92%;叶绿素a、叶绿素b及叶绿素总含量分别降低40.16%、43.24%和39.52%;ZR、IAA、GA含量,GA/IAA和ZR/IAA均高于正常苗,而ZR/GA显著低于正常苗;叶绿体数量减少、体积变小、类囊体叠跺不整齐,细胞核畸形或缺失。碳水化合物含量较低、激素代谢紊乱、光合结构破坏及细胞核物质减少是梨玻璃化苗的重要特征,可能是后代增殖能力显著降低的主要因素。

In vitro shoots of ＇Huangguan＇ pear（Pyrus pyrifolia Nakai）were selected as materials.Characteristics of propagation,physiology,biochemistry and ultra-structure were compared between normal and hyperhydric shoots.The results showed that proliferation ability of hyperhydric shoots was significantly lower than that of the normal shoots,the proliferated shoots derived from hyperhydric shoots were still hyperhydric and the degree of hyperdricity was increased.Compared to the normal shoots,the dry matter accumulation and starch content of hyperhydric shoots were decreased by 31.3% and 29.57% respectively,while the soluble sugar content increased by 13.92%.In addition,the contents of chlorophyll a,chlorophyll b and total chlorophyll in hyperhydric shoots were decreased by 40.16 %,43.24 % and 39.52 % respectively.Relative to normal shoots,hyperhydric shoots had higher contents of ZR,IAA,GA and the ratio of GA/IAA and ZR/IAA and significantly lower ratios of ZR/GA.Furthermore,the quality of chloroplast in hyperhydric shoots was lower than that in normal shoots,and chloroplast volume in the former was smaller than that in the latter.Moreover,the thylakoid stacked irregularly and the nucleus was deformed or missing in hyperhydric shoots.Taken together,these results suggest that the low content of carbohydrates,the disorder of endogenous hormone metabolism,the damage of photosynthetic structure,and the decrease in content of nuclear material in cells are the main features of hyperhydric shoots,which were the leading reasons for the decrease in proliferation ability of their offsprings.