Studies On The Growth And Development Of Shoots In Bambusa Emeiensis

The early growth and development patterns of shoots in Bambusa emeiensis were studied from the morphology,anatomy,physiology and molecular biology.Firstly,through two years of morphological observations,combined with the meteorological data,the morphological changes during the growth and development process of shoots were analyzed,which provide a sampling standard for the further studies.The main results are as follows:1.The different cohorts in Bambusa emeiensis have different average final base diameters and average FJOSI.The different height growth rate has been found in different growth and development stages of shoots which come from different cohorts or with different final base diameters.2.In the early growth and development process of shoots in Bambusa emeiensis,there is an allometric relationship between the growths of shoot body and shoot sheath.A strict linear relationship between height of shoot and the ratio(net height of shoot body/D value)was found.3.The elongation growth pattern of the first internode is different from the other internodes in Bambusa emeiensis,which is inconsistent with the normal distribution curve.The first internode developed earlier than the others,and the elongation rate was relatively stable.4.The initiation of elongation period in Bambusa emeiensis is different from that of Phyllostachys heterocycle.At the early stage of shoot body development,all internodes did not elongate,and the height of shoots mainly was result from the growth and development of shoot sheaths.Besides,this process of shoot body development takes a relatively long time.At the elongation period,the internodes of shoot in Bambusa emeiensis began to elongate gradually and orderly,and the elongation growth of each internode was the main reason for the height growth of shoots.5.The occurrence of FJOS marks the initial of rapid elongation period of shoots in Bambusa emeiensis.6.In the early growth and development process of shoots in Bambusa emeiensis,the maturity of a node was earlier than that of the adjacent internode.The internodes are always beginning to elongate and grow,in which case the structure of corresponding node is relatively mature,and a little amount of starch granules are deposited in the parenchyma cells of nodes.The maturity of the nodes is from the bottom to top,successively,consistent with the maturity of internodes.7.Shoot sheaths plays an extremely important structural mechanics role in the growth and development of shoots in Bambusa emeiensis.Lack the shoot sheaths supporting,shoots cannot grow normally.The elongation of internodes or shoots need the corresponding shoot sheaths development to a certain extent.8.Within the node near the section of sheath ring,some specialized,plateshaped vascular bundles were found.Around the specialized vascular bundles,parenchyma cells with dense cytoplasm and big nucleus associated specialized vascular bundles and longitudinal vascular bundles together.The vertical vascular bundles are not exactly point to the center of the circle,which are near the specialized vascular bundles,while,turning to the specialized vascular bundles.Moreover,in the radial proximal end of specialized vascular bundles,there are abundant phloem ganglion.These specialized vascular bundles and its surrounding tissues may constitute a material transport center within the nodes,linked internodes,nodes and shoot sheath together closely.