继代培养次数对杜梨生根能力和叶形态及其激素水平的影响

为了探索杜梨组培复幼变化规律,对10年生杜梨进行连续继代培养,统计不同继代次数杜梨丛生芽繁殖系数和生根率,观察记录叶片形态变化并测定内源激素含量。结果表明:(1)通过连续继代培养,杜梨丛生芽生根率由0提升到66.70%,繁殖系数由第1代的2.13提升到第10代的4.20。(2)叶片在继代第3次时出现裂刻且随后裂刻程度逐代加深;在继代过程中,丛生芽叶面积和叶脉数显著降低,叶周长和叶形指数呈先下降后上升的变化趋势。(3)丛生芽叶片内源IAA含量在继代第6次时达到46.39 ng·g-1,且显著高于初代丛生芽;随着继代次数的增加,叶片内源ZR呈先上升后下降的变化趋势,内源GA3含量没有发生显著性变化,而内源ABA含量逐渐降低;叶片IAA/ABA和IAA/ZR的值随着继代次数的增加而增加。(4)丛生芽叶片ABA含量和IAA/ZR与其生根率分别呈显著负相关和显著正相关关系,叶片裂刻数和IAA/ABA与生根率均呈现极显著正相关关系,而叶脉数与生根率则呈现极显著负相关关系。研究认为,连续继代培养可显著提高杜梨丛生芽的生根能力,并且与丛生芽叶形和激素含量及其比值有密切的关系,该研究结果为难生根植物无性繁殖以及树木复幼提供了重要技术借鉴。

Effects of Subculture Times on Rooting Ability, Leaf Morphology and Hormone Level of Pyrus betulaefolia

In order to explore the variation law of rejuvenation based on tissue culture, we selected 10 year old Pyrus betulaefolia for continuous subculture, and then counted the propagation coefficient and rooting rate of multiple shoots of different subculture passages. We also observed and recorded the morphological changes of leaves and measured the content of endogenous hormones. The results showed that: (1) the rooting rate of multiple shoots increased from 0 to 66.70% and the propagation coefficient increased from 2.13 in the first subculture to 4.20 through continuous subculture. (2) The leaves showed a lobes at 3rd subculture and then the degree of lobes gradually deepened; during the continuous subculture, leaf area and vein number of multiple shoots were decreased significantly, and leaf perimeter and leaf index showed a trend of decreasing firstly and then increasing. (3) The endogenous IAA content of multiple shoots reached 46.39 ng·g^-1 at 6th subculture, which was significantly higher than that of 0th subculture; with the increase of subculture passages, the endogenous ZR showed a trend of increasing firstly and then decreasing, and the endogenous GA₃ content did not change significantly, while the endogenous ABA content gradually decreased in the leaves; the values of IAA/ABA and IAA/ZR in the leaves increased with the number of subculture. (4) The ABA content and IAA/ZR of multiple shoots leaves showed significantly negative correlation and significantly positive correlation with rooting rate. The number of leaf lobes and IAA/ABA showed a significantly positive correlation with rooting rate, while the number of leaf veins showed a significantly negative correlation with rooting rate. It can be seen that continuous subculture can significantly improve the rooting ability of P. betulaefolia multiple shoots, and it is closely related to leaf morphology and hormone content and ratio of multiple shoots, which provides reference for vegetative propagation of difficult rooting plants.