East Malling Research, New Road, East Malling, Kent ME19 6BJ, UK.
J Exp Bot. 2012 Sep;63(14):5093-104. doi: 10.1093/jxb/ers155. Epub 2012 Jul 12.
Co-ordination of metabolic and physiological activity between plant parts is key to the control of growth and development. Here the movement of resources and their allocation between mother plants and daughter ramets along Fragaria stolons was quantified with respect to hierarchy. Gradients of internodal ramet leaf water potential (ψ) and stolon and ramet hydraulic conductivities (L) were measured together with apparent stolon IAA movement via the polar auxin transport pathway (PAT). These processes are linked with measurements of stolon vascular development. The pattern of tissue differentiation and lignification in sequential stele sections of stolons demonstrated the rapid acquisition of the capacity for water transport, with transpiration potentially varying systematically with stolon lignification and the acropetal decline in stolon xylem ψ. Stolon and ramet L declined acropetally, with L across older ramets being significantly lower than that of the connecting stolons. The capacity for polar IAA transport increased with stolon age; this was due to increased transport intensity in older tissues. The partitioning of dry matter was strongly hierarchical with younger ramets smaller than older ramets, while foliar concentrations of N, P, and K were greater for the younger ramets. The results show that stolon anatomy develops rapidly at the apical end, facilitating hierarchical ramet development, which is evident as a basipetal increase in L. The rapid development of transport tissue functionality enables young unrooted ramets to acquire water, in order to supply an expanding leaf area, as well as mineral ions disproportionally with respect to older ramets. This facilitates colonization and self-rooting of apical ramets. The unidirectional increase in basipetal PAT along stolons facilitates hierarchical ramet development.
植物各部分之间代谢和生理活动的协调是控制生长和发育的关键。本研究定量分析了草莓匍匐茎中母株和子株之间资源的移动及其分配与等级结构的关系。测量了节间子株叶片水势（ψ）和匍匐茎及子株水力传导度（L）梯度，同时通过极性生长素运输途径（PAT）测量了明显的匍匐茎 IAA 运动。这些过程与匍匐茎血管发育的测量有关。匍匐茎连续茎段的组织分化和木质化模式表明，其快速获得了运输水分的能力，蒸腾作用可能与匍匐茎木质化和木质部 ψ 的向顶下降系统变化。匍匐茎和子株 L 向顶端逐渐下降，较老子株的 L 明显低于连接的匍匐茎。极性 IAA 运输的能力随匍匐茎年龄的增加而增加；这是由于较老组织中的运输强度增加。干物质的分配具有很强的等级性，年轻子株比老年子株小，而年轻子株的叶片氮、磷和钾浓度较高。结果表明，匍匐茎解剖结构在顶端快速发育，促进了等级结构的子株发育，这表现为 L 的向基增加。运输组织功能的快速发展使年轻的无根子株能够获得水分，以供应不断扩大的叶片面积，以及相对于老年子株不成比例的矿物质离子。这有利于顶端子株的定植和自生根。匍匐茎中沿向基方向 PAT 的单向增加促进了等级结构的子株发育。
