Studies On Physiological Characteristics Of Main Rhizomatous Grasses

The thesis studied on physiological characteristics of main rhizomatous grasses. The contents were composed of the difference and regularity in phonological periods and the biomass, the correlation between above-ground parts of plants and under-ground parts of plants, the correlation of nutrient growth and regenerative growth, the difference and correlation in nutrients distribution and photosynthetic traits in different phase, the dynamics of endogenous hormones content and the way controlling plant development, as well as the exploration between seed dormancy and rhizomatous development. The main purpose is to indicate the developmental traits in seven rhizomatous grasses. The regeneration periods of rhizomatous grasses were 250 days longer than others, and the difference in species, genera and different rhizomatous types were not obvious. The sexual reproduction periods were shorter than vegetative repoduction periods in long-rhizome types. In periods of nutrient growth, the lasting time of the early vegetative developing periods and the late vegetative developing periods was remarkably different in species, genera and different rhizomatous types. The development dynamics of above and under ground parts of plants showed difference in different rhizomatous types. The curves of the biomass of above ground showed one lop. The curves of the biomass of under ground showed "S" forms. The curves of root-shoot ratio showed "U" forms. But the different rhizomatous types had different varication degree. The contents of major elements (nitrogen, phosphor, potassium and carbohydrate) were obviously different in different developmental phases, different organs, and different rhizomatous types. And the peak values of the contents were complementary between root and shoot, nutrient growth and regenerative growth. The corrlation between soluble sugar contents and growth center was remarkable. The peaks of starch contents and soluble sugar were complementary. Soluble sugar played an important role in rhizomatous development. There was obviously difference of ABA yearly dynamics in different rhizomatous grasses. It might be contributed to their seed dormancy. It was primarily concluded that there was a possibility that ABA could be transported from rhizomatous to dormancy organs. A positive correlation existed between the degree of seed dormancy and the length of rhizomatous. In under-ground organs, the content of ZR was the lowest in three hormones. There were a small peak of ZR content in rhizomatous of long, mid-long rhizomatous, while short rhizomatous grasses was not so. It is primarily thought that the small peak of ZR was to make the growth center transfer to under organs in the late vegetative developing periods. The yearly dynamics of GA3 in root was double peak curve. The first peak value was significantly higher than the second one, and they correlated with the two peaks of the above ground organs' nutrient growth. The main function was to advance the development of nutrient organs above ground. The yearly dynamicses of photosynthetic rate (Pn), water utility efficiency (WUE), stomatal conductance (Gs), intercellular carbon dioxide concentration (Ci) were nearly consistent, and they all single peak curves. The yearly dynamics of transpiration rate (Ti) was opposite to Pn, WUE, Gs, Ci. Different developmental stages and different types of rhizomatous both had different nitrate reductase activity. The daily varivation of photosynthesis rate in rhizomatous grasses were all double peak curves. The seed of the seven species of rhizomatous grasses were all dormant. Their seed germination rates, germination indices, and dormancy were significantly different. The extent of seed dormancy was concerned with rhizomatous types. The longer the rhizomatous were, the more dormancy the seeds were.