The Abscisic Acid Regulation Mechanism for Clonal Growth of Hippophae rhamnoides ssp. sinensis

Most researches focus on external mechanisms for the clonal growth regulation of Hippophae rhamnoides ssp. sinensis. In order to explore the Abscisic acid regulation mechanism for its clonal growth regulation. The soil water gradients were prepared by controlling the irrigation intensity. The responses of the clonal growth parameters, ABA content, and the ratios of ABA/IAA, ABA/ZR, and ABA/GA₃ to the water gradients were analyzed, and the causal relationships between them were further examined. The findings indicated that the clonal growth (ramets, clonal propagation, clonal proliferation), increased first and then decreased with increasing irrigation intensity, while the ABA content and its ratios to other plant growth regulators showed a reverse trend. Therefore, with the change of irrigation intensity as ′deficit-balance-surplus′, the clonal growth of the plant patterned as ′scatter-cluster-scatter′, being regulated by ABA. The ramet in ′cluster′ is thickset with large quantity and strong in diffusion ability, which is beneficial to population stability and clonal persistence. The situation of the ′scatter′ is just the opposite of the ′cluster′, being favor to population adaptation to water stress at the expense of reducing the ramets growth, clonal propagation and the diffusion ability, which increased the probability of premature aging.