Molecular Basis for Organization of Photosynthetic Functions through Plant Body

1. 细胞分裂素作为器官到器官的信号，从根传递到茎，表明土壤中硝酸盐的存在。鉴定了对细胞分裂素有反应的传感器激酶。His-Asp磷传递系统的其他组成部分（即反应调节因子和含his的光递质），涉及细胞分裂素信号的转导，也被鉴定和表征。此外，还鉴定并鉴定了与植物昼夜节律产生有关的伪反应调节因子。腺苷酸异戊烯基转移酶是细胞分裂素的一种生物合成酶，在拟南芥中发现了编码腺苷酸异戊烯基转移酶的基因，表明这种植物激素是由植物自身合成的，而不是由共生微生物合成的。水稻韧皮部汁液含有某些蛋白质，包括硫氧还蛋白h和几种mRNA。结果进一步表明，这些大分子中至少有一部分是在伴生细胞中合成的，并通过胞间连丝转移到筛元上。谷氨酰胺合成酶和谷氨酸合成酶同工酶分别位于叶片维管束和成熟籽粒中，它们在水稻叶片氮素的动员和向籽粒的转运中起着重要作用。硫酸盐转运蛋白和硫酸盐同化酶的编码基因在拟南芥和其他植物中被鉴定出来。发现了硫和氮同化途径之间的调节联系。

1. Cytokinin was shown to act as the organ-to-organ signal, transmitted from the root to shoot, for the presence of nitrate in the soil. The sensor kinase responsive to cytokinin was indentified. Other components of the His-Asp phosphorelay system (i. e. response regulators and His-containing phophotransmitters), implicated in transduction of the cytokinin signal, were also identified and characterized. In addition, pseudo-response regulators, implicated in generation of circadian rhythm in plants, were identified and characterized.2. The genes encoding adenylate isopentenyltransferase, a cytokinin biosynthesis enzyme, were identified in Arabidopsis thaliana, demonstrating that the plant hormone is synthesized by the plant and not by symbiotic microorganisms.3. Phloem sap of rice was shown to contain certain proteins, including thioredoxin h, and several mRNA species. It was further shown that at least some of these macromolecules are synthesized in the companion cell and transferred to the sieve element via plasmodesmata.4. A particular set of glutamine synthetase and glutamate synthease isozymes, which are localized in the vascular bundle of leaf blade and maturing grains, respectively, was found to play an important role in mobilization of leaf nitrogen and its transfer to rice grains.5. Genes encoding sulfate transporters and sulfate assimilating enzymes were identified in A. thaliana and other plants. Regulatory links between the sulfur- and nitrogen-assimilating pathways were found.