中国沙棘克隆生长对灌水强度的响应规律及其激素调控机制

关于中国沙棘克隆生长调节研究目前局限于外在机制,旨在探讨其克隆生长对灌水强度的响应规律及其激素调控的内在机制。结果表明:随着灌水强度的增大,分株生长、克隆繁殖、克隆扩散能力先升后降,IAA(吲哚-3-乙酸)、ZR(玉米素核苷)、GA_3(赤霉酸)含量及其与ABA(脱落酸)的比值先升后降而ABA含量先降后升。同时,分株生长、克隆繁殖、克隆扩散能力与IAA、ZR、GA_3含量以及IAA/ABA、ZR/ABA、GA_3/ABA呈极显著或显著正相关,与ABA含量呈极显著负相关。灌水强度过小或过大,IAA、ZR、GA_3含量以及IAA/ABA、ZR/ABA、GA_3/ABA低而ABA含量高,克隆生长潜力受到抑制,种群以分株小、数量少(分布稀疏)、扩散(水平根延伸和分枝)能力弱为特征,克隆生长格局倾向于"游击型"、种群早衰概率高;灌水强度适宜,IAA、ZR、GA_3含量以及IAA/ABA、ZR/ABA、GA_3/ABA高而ABA含量低,克隆生长潜力得以充分发挥,种群以分株大、数量多(分布密集)、扩散能力强为特征,克隆生长格局倾向于"聚集型"、种群稳定性高。随着灌水强度过小-适宜-过大的连续变化,中国沙棘通过改变激素状况调控克隆生长,从而形成与灌水强度相适应的克隆生长格局连续体"游击型-聚集型-游击型",种群稳定性呈"低-高-低"的连续变化过程。由此可见:灌水强度诱导内源激素发生改变,激素特征调控克隆生长格局,克隆生长格局决定种群稳定性。

Clonal growth response of Hippophae rhamnoides ssp. sinensis to irrigation intensity and its hormone regulation mechanism

Studies of the clonal growth regulation of Hippophae rhamnoides ssp. sinensis have been confined to the external mechanisms. This aim of this study was to investigate the response of clonal growth to irrigation intensity and the relationship between the internal mechanism and hormone regulation. With increasing irrigation intensity, the growth capacity, clonal propagation, and clonal expansion of the ramets first increased but then decreased. This trend was also observed for IAA (Indole-3-acetic acid), ZR (Trans-zeatin-riboside), and GA₃ (Gibberellic acid), and their ratios to ABA (Abscisic acid), while ABA content showed the opposite trend. The growth capacity, clonal propagation, and clonal expansion were significantly positively correlated with the contents of IAA, ZR, and GA₃, and the ratios of IAA/ABA, ZR/ABA, and GA₃/ABA, while significantly negatively correlated with ABA content. Deficient or excessive irrigation lowered the contents of IAA, ZR, and GA₃ and the ratios of IAA/ABA, ZR/ABA, and GA₃/ABA and increased ABA content. Clonal growth potential was inhibited and the populations were small ramets, showing a low quantity (sparse distribution) and weak expansion (horizontal root extension and branching). The clone growth was patterned as "guerrilla," and the population was prone to presenility. Appropriate irrigation intensity increased the contents of IAA, ZR, and GA₃, and their ratios to ABA and decreased the ABA content, indicating the cloning growth potential. The populations were characterized as having large ramets, high quantity (density distribution), and strong expansion ability. The clone growth was patterned as "aggregation," and populations were stable. With increased irrigation from deficiency to adequacy to excess, the clonal growth was patterned from guerrilla to aggregation to guerrilla in response to the irrigation intensity by regulation of hormone conditions, and the population stability changed from low to high to low. The change in endogenous hormones, which was induced by irrigation intensity, regulated the clonal growth pattern, which determined the population stability.