A Research On Characteristics Of Both Rhizome And Fine Root Of Phyllostachys Praecon Stand

Phyllostachys praecon is a kind of important forest resources in China. Phyllostachys praecon is an indigenous bamboo species with characteristics of delicious, nutrition bamboo shoots, which was original growth in Anji, Ling’an, Zhejiang province. What is more, bamboo shoots are yielded during Spring Festival, which is rich the festive dishes of people.Phyllostachys praecon has been introduced and cultivated in many places in recent years, which made a high economic benefit, promoted the local economic development. As both the planting area and the market demand increasing, it has being very important for Phyllostachys praecon intensive and sustainable management.At the moment, Chongyang county of Hubei province is the largest Phyllostachys praecon cultivation base in central China. With different stands (soil covered or not; hook tip or not), a research has been carried out into bamboo structure, rhizome quantity and its spatial distribution, shoot growth process, fine root biomass and its turnover ratio, results were as following:(1) An intensive management was necessary for Phyllostachys praecon bamboo shoot high and stable yield, and stand structure adjustment and maintenance was an effective way. The stand structure with high bamboo shoot yield for Phyllostachys praecon should be:the stem density15000/hm2with1-4a age class; choosing healthy shoots distributed evenly in the forest land, and let new bamboo shoots growing well; hook tip was also necessary for Phyllostachys praecon in order to keep snow damage away; although the number of branch round decreased after hook tip, the average leaf area index for single stem increased, so there was no negative impact on Phyllostachys praecon stand.(2) it is necessary to keep both rhizome system and lateral bud in good health for growth of both bamboo and shoot of Phyllostachys praecon, to maintain rhizome in young condition with1-4a age class by means of digging out old age rhizome every year. With the increase of soil depth, the rhizome number decreases gradually, and young and strong rhizome were mainly distributed in0-30cm soil layer. Strong buds, shoot buds and dormancy buds were mainly distributed in the young and strong rhizome, dead buds mainly distributed in old age rhizome. Strong buds, dormancy buds, dead buds and shoot bud number accounted for39.46%,43.49%,9.93%and7.12%of the total number of buds, respectively, and the difference of bud number among different bud types was significant.When soil covered, the number of both rhizome and lateral bud decreased, and the rhizome distribution trended to the surface of soil, the effect of forest soil covered on the bamboo growth was negative. Therefore, how to deal with the relationship between the economic benefits because of soil surface covered and forest sustainable management was key problem in practice. The production measures, such as when the soil surface should be covered, what time it should be removed, soil surface coverage material selection, thickness of the soil surface covered, coverage interval and so on, were key production technologies in practice as well.(3) There were significantly differences for charachteristics amog different order fine root, for instance fine root diameter, fine root length, specific root length and biomass. With root order increasing the average diameter of fine roots was smaller and smaller, but the fine root length, the specific root length and biomass were bigger and bigger.The fine root turnover rate was influenced by the fine root order of Phyllostachys praecon. The fine root turnover rate value for the root order were2x order fine root>1order root>2order root>3order root, and the difference of the fine root turnover rate value among each order root was significant. Except for2order fine root, the average turnover rate value of fine root decreased with soil depth increasing, but the difference was not significant.(4) Although the average single shoot weight was reduced with growth going by (initial shoot stage, bloom shoot stage and late shoot stage), shoot yield per unit area was in follow order:bloom shoot stage> late shoot stage> initial shoot stage. Although the effect of soil surface covered or not on the average single shoot weight was not significant, the effect of soil surface covered or not on shoot yield per unit area extremely significant.The new bamboo growth process was a rhythm of "slow-fast-slow", it almost completed the whole growth process within a month. The regression of height growth of the new bamboo and days was a S curve, and the new bamboo height growth could be divided into three stages:early stage with slow speed, mid stage with high speed and late stage with slow speed.