The Study On Structure And Physiological Differences Of New And Old Pseudobulbs From Cremastra Appendiculata(D. Don) Makino

The study used a method of combining morphogenesis observation, structural anatomy and physiological and biochemical analysis, to learn more about Cremastra pseudobulb process of morphogenesis and structural and physiological differences between new and old pseudobulbs during newborn pseudobulb development. The main results and conclusions are as follows:(1) Cremastra pseudobulb process of morphogenesis can be divided into six stages from the morphological changes: dormancy stage of leaf buds, germination stage of leaf buds, elongate stage of leaf buds and rhizomes, pseudobulb initial formation stage, pseudobulb intumescence stage and pseudobulb full development stage. Under the microscopic structure changes, it can be divided into seven stages: dormancy stage of leaf buds, germination stage of leaf buds, elongate stage of leaf buds and rhizomes, root differentiation stage, pseudobulb initial formation stage, pseudobulb intumescence stage and pseudobulb full development stage.(2) There is no difference between new and old pseudobulbs of Cremastra on structure composition. It all consists of epidermis, cortex, vascular bundle and the basic organization of four parts. Its closed collateral bundle atactostele is in the basic organization; its ringed vessel emerges V arrangement, which is a typical monocotyledon stem structure. The main differences are that the newborn pseudobulbs are greater than the earlier pseudobulb in the cell density and its cell size is smaller than the earlier pseudobulb, inclusions more than earlier pseudobulb.(3) Cremastra new and old pseudobulbs soluble sugar, soluble protein and endogenous hormones(IAA, CTK, GA3 and ABA) content changed regularly during the newborn pseudobulb morphogenesis. Before newborn pseudobulb buds germination, the old and new pseudobulbs soluble sugar content decreased to a minimum. The minimum of pseudobulbs soluble sugar content were annually 9.15 mg.g-1, biennially12.79 mg.g-1 and triennially 7.99 mg.g-1. Except for the slow rise of triennial pseudobulbs soluble protein content, the annual and biennial pseudobulbs soluble protein content were a sharp rise. The annual, biennial and triennial pseudobulbs soluble protein peaks were 8.60 mg.g-1, 7.38 mg. g-1 and 3.72 mg.g-1. In the new and old pseudobulbs, the annual pseudobulb IAA content decreased to a minimum; CTK content was greater than biennial and triennial pseudobulbs; ABA content decreased fastest; GA3 content rose sharply; the ratio of IAA / CTK and IAA / ABA decreased to a minimum. Above all, the budding ability of newborn pseudobulb was comprehensively controlled by the soluble sugar, soluble protein and the changes of endogenous hormone(IAA and CTK, GA3 and ABA) content.(4) According to the significant difference analysis, in each stage the development of newborn pseudobulb, the differences between soluble sugar and endogenous hormones(IAA, CTK, GA3 and ABA) content in old and new pseudobulbs was not significant. In the development of newborn pseudobulb dormancy stage of leaf buds, germination stage of leaf buds, pseudobulb intumescence stage and pseudobulb full development stage, the soluble protein content of annual and triennial pseudobulbs showed significant differences, and during the dormant stage and the pseudobulbs full development stage, the content showed a highly significant difference, while the differences of soluble protein content between biennial pseudobulb and annual, triennial pseudobulbs was not significant. At the same time, pseudobulbs of the same age, during different developmental stages of the newborn pseudobulb, the differences analysis result of above physiological and biochemical indexes were different.