Studies On Biology Of Chenglü Bamboo No3 Clonal Population

Chenglu bamboo is a hybrid breaded by Guangxi Institute of Forestry Science in 1980using Bambusa pervariabilis McClure as female and Dendrocalamopiss daii Keng as maleparent. Four clones, No3, No6, No8 and No30, were selected, which are suitable for cultivationin south China. Among them the clone of No3 has been mostly cultivated. In 2003, the clone ofNo3 was introduced to north Guizhou for the purpose of pulping. The biological and ecologicalcharacters of Chenglu bamboo No3 clonal population were investigated in this paper.The effects of main site factors on the growth of the clone No3, using multiple regression,were analyzed. The results showed that: (1) The altitude, slope position, soil thickness andsloppiness were the leading factors which had the significant effects on the growth of the cloneNo3. (2) According to the leading factors, 3 site type regions, 6 sub-regions of site type, 12site type groups and 72 site types were divided. (3) Combining with the result from t-test, thebest suitable site types wereâ… Cb5 andâ… Sb5. The suitable site types wereâ… Cb6,â… Cb3,â… Sb6,â… Sb3,â…¡Cb5,â…¡Sb5. The not well suitable site types wereâ… Cb4,â… Sb4,â…¡Cb6,â…¡Sb6 and the unsuitable were allâ…¢(≥800m) and all a(upper slope) or 1 and 2 (thin soil).The development of young culm of the clone No3 was observed successively in 104 days.(1) The observed results showed that the height growth process of the Chenglu Zhu No.3 wasdivided into the initial period, peak period and end period according to the Fisher method.(2)The mathematical model of the height growth is Y=-7.8784+0.4659t+0.1663t²-0.0008t³,with R²=0.996. (3)The height growth was different between the daytime and the nighttime.The total trend was that the growth at nighttime was greater than that at daytime. The heightgrowth at nighttime could account for 67.2% of the total growth of one day, but the growth atdaytime was only 32.8%. The lowest growth rate was at 14:00 and the fastest rate were at 2:00and 6:00. (4)The relative humidity, the maximum temperature and sunny hours had asignificant negative effects on the height growth. But the rainfall, mean daily temperature andminimum temperature had no significant effect on it.The investigation of vegetation spaces of Chenglu bamboo No3 clone showed that foursite factors as soil thickness, altitude, slope position and slope degrees affected the spaceextension significantly. But the factors like different slope directions and soil types does notaffected significantly. (1) The sites with thin soil, above 800m, or upper slope were poor for the bamboo clump crown dimension extension, so were not suitable for the planting thebamboo. (2) The sites with thin soil, above 800m, or slope degree with more than 16°was poorfor the bamboo stump dimension extension, so were not suitable for the planting the bamboo.(3)The differences of the site conditions had the effects on the vegetation space extension, so asto the planting density. A unifying planting density was not practicable. The density of 3m×4mcould be used in well site, but in the poor site with mid soil thickness,the planting densitywould be increased to 3m×3.5m or 3m×3m for fastening the early crown closed.The results of the analysis of biomass were as follows: (1)The factors of diameter, height,culm weight, branch weight, leave weight, and the total aboveground weight have the closelyrelationship, with a more significant level. (2)The equation between biomass and the diametersis W=0.0849D2^2.0036. (3)The biomass distribution show that culm＞branch＞leaf. The biomassof the single culm increased with the ages. The bigger the diameters, the more the biomass.(4)The average culm biomass is 15.3kg,and the biomass of the plantations are 12 500.0～16666.7kg/hm². (5)According to the cluster analysis, the plantations could be divided into 5 types,the lowest yield plantation, low yield plantation, mean yield plantation, high yield plantationand the super high yield plantation.The water contents of bamboo culms varied with the different ages, 1a (71.5%)＞2a (56.3%)＞3a(47.9%). The water contents varied also with the different height along a single culm,base (62.4%)＞middle (59.0%)＞upper (54.4%).The observation of root vigor showed that 2a one＞3a one＞1a one.The chlorophyll contents of the foliage leaf at different aged culms are 2a one＞1a one＞3a one. The content of chlorophyll of the foliage leaf at different positions of a single culm arebase one＞middle one＞upper one.The optimum model between the diameter and the leave areas is M=91974.8-50277D+10460.2D²-56.144D³, R²=0.9012. The leaf area index of the plantations at moment is mostlybelow 6. This means that these plantations do not reach the high yield structure.The fiber characters varied with the culm positions and ages. The length and width offiber are 1990.23μm and 13.65μm respectively in average. The rate of length to width is 145.87.It indicated that the clone No3 is suitable for paper-making. Meanwhile, some chemicalcompositions related paper-making were analyzed. The holocellulose is 67.54%.The chemicalcompositions also show that this bamboo is a good bamboo for pulping.The trial result of plantation structure regulation shows that some old bamboos should beremained in the plantation. The traditional harvest modle "all cut each four year" is notrationale. The felling intensity should not be more than 60%. Through the analysis of soil nutrients and bamboo nutrients, the results show that thedemands of N,P,and K for the bamboo are 83.34Kg/hm²,15.38Kg/hm² and 72.43Kg/hm², witha proportion of 5: 1: 5. The practical use is 6: 1: 0, so the proportion of fertilization in theproduction should be regulated.The pests and diseases of the Chenglübamboo No3 clone were identified. There are 14fungal diseases and 22 species of pests. The genetic rules of main pests were preliminarilystudied. The species of pests and diseases are more than the reported, so it should be intensivelymonitored and controlled to make the healthy development of the bamboo clonal population.