Jiang Fan, Veselova Sveta, Veselov Dima, Kudoyarova Guzel, Jeschke W Dieter, Hartung Wolfram
Lehrstuhl Botanik I der Universität Würzburg, Julius-von-Sachs-Platz 2, D-97082 Würzburg, Germany.
Institute of Biology of Russian Academy of Sciences, Ufa Research Center, pr. Octyabrya, 69, Ufa 450054, Russia.
Funct Plant Biol. 2005 Aug;32(7):619-629. doi: 10.1071/FP04168.
Using the facultative root hemiparasite Rhinanthus minor L. and Hordeum vulgare L. as a host, the flows, depositions and metabolism of zeatin-type cytokinins [zeatin (Z), zeatin riboside (ZR), zeatin nucleotide (ZN)] within the host, the parasite and between host and parasite have been studied during the period 41-54 d after planting (i.e. ~30-43 d after successful attachment of the parasite to the host). Parasitism decreased the synthesis of Z in the root (by 57%) and decreased xylem flows (by 56%) and metabolism (by 71%) in leaf laminae. However, phloem flows of Z were increased by 3-fold in the host barley. The deposition of Z in the roots of Rhinanthus and the flows in xylem and phloem were increased by 20, 12, 29-fold, respectively, after successfully attaching to the host barley. However, net biosynthesis of Z in Rhinanthus roots decreased by 35% after attachment. This indicates that a large portion (70%) of xylem flow of Z in attached Rhinanthus was extracted from the host. In singly growing Rhinanthus plants, the balance of Z deposition in the shoot was negative (i.e. Z was metabolised and exported back to root in the phloem). Xylem flows and deposition of ZR and ZN showed comparable quantitative changes after attachment. A significant deposition of Z, ZR and ZN was detected in the haustoria of the Rhinanthus / barley association. The possible physiological functions of the large quantities of Z and ZR and ZN derived from the host barley, for the improved leaf development and the stomatal reactions of the parasitising Rhinanthus are discussed.
以兼性根半寄生植物小花山萝花（Rhinanthus minor L.）和大麦（Hordeum vulgare L.）作为宿主，研究了在种植后41 - 54天期间（即寄生虫成功附着于宿主后约30 - 43天），玉米素型细胞分裂素[玉米素（Z）、玉米素核苷（ZR）、玉米素核苷酸（ZN）]在宿主、寄生虫以及宿主与寄生虫之间的流动、沉积和代谢情况。寄生作用降低了根中Z的合成（降低57%），并降低了叶片木质部的流动（降低56%）和代谢（降低71%）。然而，宿主大麦中Z的韧皮部流动增加了3倍。小花山萝花成功附着于宿主大麦后，其根中Z的沉积以及木质部和韧皮部的流动分别增加了20倍、12倍和29倍。然而，附着后小花山萝花根中Z的净生物合成下降了35%。这表明附着后的小花山萝花中Z的木质部流动的很大一部分（70%）是从宿主中获取的。在单独生长的小花山萝花植株中，地上部Z沉积的平衡为负（即Z被代谢并通过韧皮部运回根部）。附着后ZR和ZN的木质部流动和沉积显示出类似的定量变化。在小花山萝花/大麦组合的吸器中检测到大量Z、ZR和ZN的显著沉积。讨论了源自宿主大麦的大量Z、ZR和ZN对寄生小花山萝花叶片发育改善和气孔反应可能的生理功能。
