细胞分裂素对植物生长发育的调控机理研究进展及其在水稻生产中的应用探讨

细胞分裂素(cytokinin, CTK)对植物的形态、生理及产量有重要调控作用,是调控氮素吸收、转运与代谢的主要因子之一。本文概述了氮素的吸收、转运、代谢以及CTK的代谢、转运和信号转导路径,重点阐述了CTK与氮素协作调控根-冠关系的生理机制,即反式玉米素(tZ)及其核苷(tZR)受氮素诱导在根中合成,并转运至地上部,调控地上部氮的转运及分布,影响氮代谢酶的生理特性,从而影响植株光合特性及产量;冠层中氮能够诱导异戊烯基腺嘌呤(iP)及其腺苷(iPR)的合成,并通过韧皮部转运至根系,抑制根系氮素吸收、转运,抑制根系形态建成。在此基础上,进一步论述了CTK在协调源-库关系及提高籽粒充实度方面的作用,分析了栽培措施对CTK生理代谢的影响及其与作物生长相关的机理。同时探讨了CTK上述功能应用于水稻大田生产时存在的问题,并对今后的研究方向提出了建议。

Regulations of Plant Growth and Development by Cytokinins and Their Applications in Rice Production

Cytokinins (CTKs) play important roles in regulating crop morphology, physiology, and yield. In the development of crops, CTKs are the main factors controlling the uptake, translocation, and metabolisms of nutrients, especially for nitrogen. In this paper, we summarized the uptake, translocation and metabolism of nitrogen, and synthesis, translocation and signaling of cytokinins, with a focus on the coordination of CTKs and nitrogen in regulating root-shoot relationships and their influences on crop agronomic traits. Generally, the synthesis of trans-zeatin (tZ) and tZ riboside (tZR) was up-regulated by nitrogen in roots, and they are translocated to shoots, regulating the portioning and metabolism of nitrogen, influencing the photosynthetic characteristics and yield. In shoots, the synthesis of N⁶-(Δ²-isopentenyl)- adenine (iP) and iP riboside (iPR) were up-regulated by nitrogen, and they are translocated to roots by phloem, reducing the uptake and translocation of nitrogen, influencing the root morphology. Based on current knowledge, we further discussed the role of CTKs in coordinating source-sink relationships and improving grain filling. We also analyzed the influence of cultivation practices on metabolism of CTKs and its correlation with crop growth. At the same time, we also discussed the existing problems in the application of CTKs in rice production systems. We hope that it could provide valuable information for high yielding and high efficiency rice production.