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Tan X.-M.,Chinese Academy of Forestry | Tan X.-M.,Chongqing Academy of Forestry | Jin G.-Q.,Chinese Academy of Forestry | Zhou Z.-C.,Chinese Academy of Forestry
Forest Research | Year: 2011

Combining ability of seedling height and shoot elongation parameters for the third generation germplasm of Pinus massoniana were investigated with a 6×6 half diallel cross design, and the parents were selected from the second generation breeding population. The result showed that the net increment of initiation phase, linear phase and later phase of seedling height took 22.82%, 59.05% and 18.13% of the total increment respectively, the increment at linear growth stage played a decisive role in the total increment of seedling height. The result of combining ability showed that, except for total linear growth (TLG), there were not significant differences in general combining ability (GCA) of seedling height, maximum growth rate (MGR), linear growth day (LGD) and linear growth rate (LGR), but for specific combining ability (SCA), except for LGD, there existed significant differences in seedling height, MGR, TLG and LGR, and the dominant gene effect was predominant over the additive gene effect. The reason for this seemed to be that the indirect selection of GCA had been made on mating parents. Compared to the second generation germplasm, which the mating parents had been indirect selected on GCA, the change was little for genetic control model of this trait in the third generation germplasm, and only the variance component of SCA increased to a certain extent.

Xue P.P.,Chongqing Academy of Forestry | Xue P.P.,Beijing Forestry University | Wang B.,Beijing Forestry University | Wang B.,Chinese Academy of Forestry | Niu X.,Beijing Forestry University
Plant Biosystems | Year: 2015

The contribution of fine roots to forest ecosystem health (FEH) is still poorly understood, although fine roots are recognized to provide benefits to ecosystems. To address the relationship between fine roots and forest health, minirhizotrons was used to observe fine root ( < 2 mm) dynamics during a 1-year period in nine Moso bamboo [Phyllostachys pubescens Mazel ex J. Houz.] plots having three levels of forest health (health, general health, and sub-health) 6 months after minirhizotron installation in the Dagang mountains (China). Forest health status was assessed by an improved Costanza model in 2011, 3 years after the great 2008 Chinese ice storm. Fine root number, length, and turnover in health plots were significantly higher than those in general health and sub-health plots, indicating that fine root number, length, and turnover rate were positively correlated with forest health condition. On the contrary, fine root diameter increased from 0.39 ± 0.03 to 0.52 ± 0.04 mm as forest health decreased, suggesting a strong negative correlation between fine root diameter and forest health condition. Fine root turnover rate ranged from 0.68 ± 0.19 to 1.37 ± 0.32 year− 1 as forest health condition increased. All trees in the nine plots showed a unimodal peak of fine root production with distinct seasonality. The fine root number growth rate peaked in mid-summer and declined over the remainder of the growing season. Thus, fine root of Moso bamboo appear highly sensitive to forest health status, and this study concluded that fine root turnover rate of the minirhizotron tube surface can be used as an indicator to assess FEH in Dagang mountain. © 2014 Società Botanica Italiana.

Tong L.,Chinese Academy of Forestry | Wang L.,Forest Bureau of Rongchang County | Xie J.-Z.,Chinese Academy of Forestry | Chen L.-J.,Chongqing Academy of Forestry | And 2 more authors.
Forest Research | Year: 2015

In order to understand the influence of truncation on canopy biomass accumulation, distribution and branch and leaf size of Dendrocalamus latiflorus, the modular biomass, biomass ratio, leaf area and dry weight, the size of branch biomass distribution ratio and the quantity of commodity leaves of D. latiflorus with different ages were measured and analyzed. The results showed that the aboveground modular biomass of D. latiflorus was in the order of stem>branch>leaf. The leaf biomass, leaf/branch biomass ratio and leaf/stem biomass ratio showed a trend of 2a > 3a > 1a. With the increase of age, the aboveground biomass, branch biomass, stem biomass branch/stem biomass ratio of D. latiflorus followed an increasing trend. The allocation proportion of branch biomass and leaf biomass of 2- and 3-year-old D. latiflorus were significantly higher than that of 1-year-old D. latiflorus, while the allocation proportion of stem biomass of 2- and 3-year-old D. latiflorus were significantly lower than that of 1-year-old D. latiflorus. In order to improve the spatial expansion capability to intercept more light resources, the D. latiflorus stand reduced the 0-8 mm branch biomass allocation, while increased the branch biomass input of the 8-16 mm, 16 mm or above. Truncation strongly affected the biomass distribution pattern, significantly reduced the branch, leaf, stem, and aboveground biomass. After truncating, the D. latiflorus stand increased the allocation proportion of branch biomass and leaf biomass, reduced the allocation proportion of stem biomass. At the same time, it improved the single leaf area and dry weight and increased the biomass allocation proportion of 8-16 mm, 16 mm or higher branch, reduced the biomass allocation proportion of 0-8 mm branch for the purpose of balancing the growth of branch and leaf, and improve the environmental suitability of truncated D. latiflorus. After D. latiflorus stand was truncated, the biomass ratio of leaf/branch, leaf/stem, and branch/stem increased, indicating that the biomass allocation inclined to the leaf and branch. Truncation reduced the picking height, the results showed that after D. latiflorus was truncated, the commodity leaf increased by 29.68% compared with the untruncated stand, the number of commodity leaf at the bottom of canopy increased by 79.73% and that in the middle of canopy increased by 25.81%. The change of the relationship between branch and leaf showed that truncation influenced the resource utilization strategy of D. latiflorus stands in the first growing seasons after truncating. However, further studies on change regulation with the age of truncation are needed. ©, 2015, Chinese Academy of Forestry. All right reserved.

Zhou Y.-Q.,Chinese Academy of Forestry | Zhou Y.-Q.,Chongqing Academy of Forestry | Gu X.-P.,Chinese Academy of Forestry | Wu X.-L.,Chinese Academy of Forestry | And 2 more authors.
Forest Research | Year: 2011

Sympodial bamboo is an important bamboo resource in China. Three sympodial bamboo plantations (Dendrocalamus farinosus, Bambusa pervariabilis × Dendrocalamopsis daii, and Bambusa rigida) planted in Southern Sichuan province were studied. Four pairs bamboo buds which located at stem basal were named at first bud, second bud, third bud and fourth bud from bottom to top in sequence, bamboo shooting and growth of four pairs bamboo buds were surveyed. The survival rate of bamboo shoots, shooting rate and relative growth rate of mother bamboos with different ages and buds location were calculated respectively. The result showed that the reproductive capacity decreased rapidly with increasing age, one-year-old mother bamboo had the best reproductive capability, but decreased quickly in the second year, and the mother bamboo almost lost reproductive capacity in the third year. For different bamboo buds locations, the shooting rate and survival rate of bamboo shoots were in the order of second bud>first bud>third bud>fourth bud, the first and the second buds were significantly higher than the third and the fourth buds. The result of analyzing the effect of age of mother bamboo and bud location on the ability of bamboo shooting showed the germination ability of the first and the second buds at one-year-old mother bamboo were the optimal. By sequential sample cluster analysis, the shooting period was divided into three stages: initial, abundant and final stage. The number of shoots at the initial shooting stage was few, but the survival rate of bamboo shoots was very high, the abundant and final stage showed the opposite situation. Germination age and shooting time of bamboo buds were related with the buds locations, the germination age and shooting time of the first and the second bamboo buds located in middle and lower location were earlier than that of the third and the fourth bamboo buds. Based on their study, the authors proposed some suggestions for tending, intermediate cutting, fertilization and shooting control.

Fang W.,Southwest University | Fang W.,Chongqing Academy of Forestry | Liu Y.,Southwest University | Ma L.,Southwest University | And 3 more authors.
Journal of Food, Agriculture and Environment | Year: 2014

Influences of litter mixing on leaf litter decomposition, N, and P releases were investigated in a Pinus massoniana plantation ecosystem in montane China. The hypothesis was tested that the decomposition rate and nutrient release of P. massoniana litter was promoted by litters of native broadleaved trees (Cinnamomun camphora, Quercus fabri, Camellia spp.) with high quality during mixing decomposition, whereas the decomposition rate and nutrient release of native broadleaved tree litters were retarded by P. massoniana litter with low quality. Therefore, a litter mixing experiment was carried out in a montane plantation forest ecosystem in China to reveal the effects of litter mixing on the litter decomposition and nutrient release. Over a 12-month period, the results showed that litter mixing had the non-additive effects on mass loss and nutrient release. The mass loss of P. massoniana was decreased by litter mixing, whereas the mass loss of Q. fabri was increased. Litter mixing increased the N release of P. massoniana litter, whereas mixing slowed the N and P release of C. camphora and Camellia spp. litter. However, litter mixing increased the N and P release of Q. fabri litter, and decreased the P release of P. massoniana litter. Our results indicated that the combinations of masson pine needle litter with other broadleaved leaf litters could synergise litter decomposition, nutrient availability and thus it had advantages in degraded soil restoration and sustainable land management.

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