Effect of Environmental Gradients on the Quantity and Quality of Fallen Logs in Tsuga longibracteata Forest in Tianbaoyan National Nature Reserve, Fujian Province,China

We investigated the quantity and quality of fallen logs in different Tsuga longibracteata forest communities in the Tianbaoyan National Nature Reserve. We used redundancy analysis to determine the spatial distribution of fallen logs in the different forest communities and to analyze the relationships among stand structure, topographic factors and human disturbance. The volume, covered area, mean log length and number of fallen logs differed significantly among forest types(P < 0.05), but mean diameter at breast height showed no significant difference(P > 0.05). The log volume and covered area in different forest types showed the following trend: T. longibracteata pure forest < T.longibracteata + Oligostachyum scabriflorur < T.longibracteata + hardwood < Rhododendron simiarum + T. longibracteata < T. longibracteata +Phyllostachys heterocycla pubescens. The spatial distribution patterns of logs quantity and quality indicated that log volume and covered area were strongly affected by environmental factors in the following order: human disturbance > elevation >slope position > bole height > tree height > slope aspect > density > basal area > slope gradient. The relative contribution of environmental variables on the total variance was topography(76%) >disturbance(42%) > stand structure(35%).Topography and disturbance combined explained83% of the variance. Fallen logs quantity and qualitywere negatively related to elevation and slope position,and positively associated to human disturbance. The log volume decreased from northern to southern slopes. Environmental factors had the highest impact on class I(slightly decayed), and lowest impact on class V(highly decayed).

Effects of forest cover types and environmental factors on soil respiration dynamics in a coastal sand dune of subtropical China

Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for secondary natural Litsea forest and plantations of casuarina,pine, acacia and eucalyptus. Results show that significant diurnal variations of Rsoccurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of Rswere found in all five forest stands. Rschanged exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of Rs variations. Positive relationships between seasonal Rsand soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter(Q10 value) of Rsranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual Rswas highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter,and soil properties(pH, total N, available P, and exchangeable Mg) were also significant factors.

Spatio-temporal Variation of Landscape Heterogeneity under Influence of Human Activities in Xiamen City of China in Recent Decade

Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern.

In vitro propagation of a medicinal plant: Tripterygium wilfordii Hook f.

In this study a reliable protocol was developed for the establishment of commercial in vitro cultures of Tripterygium wilfordii Hook f.. Juvenile shoots from one-year-old elite plants were used as the source of explants. New axillary shoots were obtained after 30 days of culture on a MS medium supplemented with BAP （2.0 mg.L^-1） and NAA （0.1 mg.L^-1）. The optimal multiplication medium was a modified MS medium supplemented with BAP （1.0 mg.L^-1） and NAA （0.1 mg.L^-1）. This yielded a multiplication rate of 2.4 for each subculture. Slightly more than 92% of shoots rooted when cultured on a modified MS medium containing IBA （0.2 mg.L^-1） and activated charcoal （0.5 mg.L^-1）. Activated charcoal promoted both a strong and a high rooting rate during the rooting phase. Plantlets were transferred to pots for a short acclimatization stage in a greenhouse where 95% of the plantlets survived. This highly reproducible procedure can be adopted for large-scale propagation of T. wilfordii.

Spatial analysis increases efficiency of progeny testing of Chinese fir

We used spatial, global trend and post-blocking analysis to examine the effectiveness of a progeny trial in a tree breeding program for Chinese fir （Cunninghamia lanceolata （Lamb.） Hook） on a hilly site with an environmental gradient from hill top to bottom. Diameter at breast height （DBH） and tree height data had significant spatial auto-correlations among rows and columns. Adding a firstorder separable autoregressive term more effectively modelled the spatial variation than did the incomplete block （IB） model used for the experimental design. The spatial model also accounted for effects of experimental design factors and greatly reduced residual variances. The spatial analysis rel- ative to the IB analysis improved estimation of genetic parameters with the residual variance reduced 13 and 19% for DBH and tree height, respectively; heritability increased 35 and 51% for DBH and tree height, respectively; and genetic gain improved 3-5%. Fitting global trend and postblocking did not improve the analyses under IB model. The use of a spatial model or combined with a design model is recommended for forest genetic trials, particularly with global trend and local spatial variation of hilly sites.

Inheritance of growth and survival in two 9-year-old, open-pollinated progenies of an advanced breeding population of Chinese firs in southeastern China

Tree growth traits （tree height, DBH and stem volume） and survival from two 9-year-old, open-pollinated progeny tests of Chinese fir were investigated for heri- tability, genotype × environment interaction, age-age genetic correlation and selection efficiency. The 97 and 79 families planted at two sites were collected from the thirdcycle seed orchard. Individual heritability was estimated between 0.05 and 0.21 for tree height, DBH, and volume and between 0.45 and 1.0 for survival. Family heritability was between 0.20 and 1.14. Significant genotype x envi- ronment interaction was observed for the three growth traits. Type B genetic correlation was between 0.41 and 0.67 with an increasing trend as tree grows. High age-age genetic correlation was observed with correlation reaching 0.9 after age 4 for height, DBH, and volume. The genetic gains were estimated at 3.26, 3.39 and 5.98 % for tree height, DBH, and volume with 10 % selection intensity. The implication for advanced tree breeding in Chinese fir is discussed.

SPARTINA CONTROL STRATEGY OF CHINA

Spartina is a kind of very important and invasive grass. In its native range, it is very important for erosion control, fish, wildlife, and estuary reclamation. Therefore, it was introduced to many countries. Since 1963, it was introduced to China. Up to now, it was intentionally or accidentally planted nearly all estuaries in the east coast of China and the area was estimated over 0.1×106 hm2. As other introduced plants, Spartina grows very vigorously in China, and this caused many environmental and economical problems. So, it is an emergency to develop a Spartina control strategy of China. In the paper, the history of Spartina introduction in China was reviewed, and several methods which were probably feasible for China to control Spartina were introduced, including physical/mechanical (such as mowing, digging, and dredging), chemical, and biological methods. Before taking any measurments to control Spartina, 2 things should be done. The first was to develop a plan and make an inventory; the second was to select a feasible method according to local climatic, economic, social, and ecological conditions. It was suggested that it would be very important to assess the possible effect of control methods on the environment in order to prevent from causing other environmental problems.

Seasonal variation and ecological importance of tannin and nutrient concentrations in Casuarina equisetifolia branchlets and fine roots

In this study,we investigated the effects of environmental factors on plant phenolic variability,seasonal dynamics of total phenolic content(TP),extractable condensed tannins(ECT),protein-bound condensed tannins(PBCT),fiber-bound condensed tannins(FBCT),total condensed tannins(TCT),protein precipitation capacity(PPC)and nutrient content in the branchlets and fine roots of Casuarina equisetifolia.TP and TCT concentrations in branchlets were lowest in the spring,then increased in summer and autumn,similar to the seasonal dynamics in air temperature.TP and TCT concentrations in fine roots were highest in summer,coinciding with heavy precipitation.In general,TP and TCT concentrations were higher in branchlets than in fine roots.No significant difference was found in C concentration among various seasons for either branchlets or fine roots.Branchlets had significantly higher N and P concentrations than fine roots in most seasons.The C/N and N/P ratios in branchlets were significantly lower than in fine roots in all seasons,except summer.The relationship between branchlets and fine roots was significant for C,P and FBCT,but no significant relationships were found for N,TP,ECT,PBCT and TCT.Additionally,TP and TCT content were each significantly correlated with PPC in branchlets and in fine roots.Both TP/N and TCT/N ratios were highest in the autumn for the branchlets and in the summer for fine roots.The results indicate that high temperatures lead to increased tannin production in branchlets,but that the tannin content in fine roots is mainly affected by precipitation.Tannin content was greater in branchlets than in fine roots,which may indicate that selective pressure is greater on branchlets than on fine roots.

The Effects on the Cutting Propagation of Cinnamomum micranthum in Different Seasons

Cinnamomum micranthum is one of China Third-class Endangered Tree Species. The seedlings of C. micranthum are difficult to obtain. It is important to study the cutting propagation of C. micranthum in different seasons to improve the rooting rate for providing seedling propagation technique for the afforestation industry. In this study,the optimal season for the cutting propagation of C. micranthum was summer( May),providing 80. 6% rooting rate. The rooting rate in Summer was 33. 4% higher than that in Spring( March). This technique is important to make the best use of rare C. micranthum resources and to provide plenty of seedlings for afforestation and greening industry.

Improvement of the tissue culture technique for Melaleuca alternifolia

Tea tree oil is extracted from the leaves and twigs of Melaleuca alternifolia （Maiden ＆ Betche） Cheel, and it is widely used in medicines, food preservatives, cosmetics and health care products. Traditional propagation of M. alternifolia from seeds does not necessarily transfer the desired characteristics from their mother trees, the seedlings are not uniform, and the multiplication rate from cuttings is relatively low. For these reasons, it is necessary to develop tissue culture techniques for this species. This study showed that an efficient explant initiation medium for M. alternifolia was MS 1/2 ＋ BA 0.6mg L^-1 ＋NAA 0.1 mg L^-1＋sucrose 30g L-l, which yielded a 75.9 % initiation rate. An efficient multi- plication medium was MS ＋ BA 0.3 mg L^-1＋ NAA 0.15 mg L^-1 ＋ sucrose 30 g L^-1, which yielded a 4.3 multiplication rate and 3.2 cm shoot length. The rooting medium was MS 1/2 ＋ IBA 0.1-0.25 mg L^-1 ＋ sucrose 15 g L^-1, which yielded a 100 % rooting rate, 2.94-3.32 roots per individual and 1.36-1.44 cm root length. Local red-core soil was suitable as a transplant medium, and yielded 98 % survival. This study improved the tissue culture technique for mass-propagation of M. alternifolia, enabling the production of high quality plants for market.

In Vitro Propagation of Ardisia mamillata Hance

Ardisia mamillata Hance is a rare plant with highly ornamental and medicinal value. The traditional propagation methods for A. mamillata by seeds or cutting provided low proliferation rate. This study is to optimize the propagation technique of A. mamillata by tissue culture and set up an industrial production system to provide plenty of A. mamillata seedlings for the human demand. The optimal initiation medium for A. mamillata is MS +2.0 mg/L BA +0.1 mg/L NAA +30 g/L sugar, providing76.4% initiation rate. The optimal shoot proliferation medium for A. mamillata is MS+1.0 mg/L BA+0.1 mg/L NAA+30 g/L sugar, providing 4.56 fold proliferation rate and3.10 cm shoot in height. The optimal shoot elongation medium for A. mamillata is MS+0.5 mg/L BA+0.1 mg/L NAA+30 g/L sugar, providing 2.77 fold proliferation rate and 4.27 cm shoot in height. The optimal rooting medium for A. mamillata is 1/2MS+0.1 mg/L IBA +15 g/L sugar, providing 99.7% rooting rate, 4.0 roots per individual,7.53 cm root in length and 3.94 cm shoot in height. This provides a reliable mass propagation method for A. mamillata.

The Chloroplast Genome of Cerasus Campanulata Diverges from Other Prunoideae Genomes

Cerasus Campanulata is one of several species belonging to the Prunoideae focke,a subfamily of the flowering plant Rosaceae.We investigated the details of its chloroplast genome which may reveal its genus independent of morphological determination.Here,we determined the complete chloroplast(cp)genome sequence of C.campanulata and performed sequence analysis to reveal the presence of 18 forward repeats,20 palindrome repeats,2 complement repeats,4 reverse repeats and 93 simple sequence repeats(SSRs).We additionally performed a comparative study of C.campanulata and seven other Prunoideae focke species.Then,maximum parsimony(MP)and maximum likelihood(ML)phylogenetic analyses were carried out in the little part of Rosaceae,respectively.The results strongly support a position of C.campanulata as a member of the Cerasus in the Rosaceae family.Moreover,the complete cp genome can be used for plant phylogenetic and evolutionary studies that will provide insight into the degree of gene conservation.

Comparison of the Effects of Pesticide Application on Biston suppressaria Larvae in Different Damage Stages

[Objective] The paper was to determine the optimal control period of Biston suppressaria, the most serious defoliator in eucalyptus forests in southern Fujian Province. [Method] By spraying 2% abamectin + Bacilus thuringiensis powder in the forest, the first generation larvae of B. suppressaria was controlled in the early damage stage(May 2), middle damage stage(May 13) and late damage stage(May 30), respectively.[Result] When 500 g of pesticide was sprayed per 667 m^(2) in the early damage stage of the first generation larvae, the population reduction rate was97.5 % at 5 d post spraying. When 500 g of pesticide was sprayed per 667 m^(2) in the middle damage stage, the population reduction rate was 95.3% at 5 d post spraying. When 1 000 g of pesticide was sprayed per 667 m^(2) in the late damage stage, the population reduction rate was 83.9%, conspicuously lower than those in the early and middle damage stage. If pesticides were sprayed in the early and middle damage stage, the second gen-eration larvae would not cause harms, but the second generation larvae would cause slight harms if pesticides were sprayed in the late damage stage.[Conclusion] Control before the middle damage stage has significant effect on improving the control effect and reducing losses while reducing the usage of pesticides.

Correlation between Inclusion Contents in Casuarina spp. Twigs and Its Resistance to Lymantria xylina

[ Objective ] The paper was to explore the correlation between inclusion contents in Casuarina spp. twigs and its resistance to Lymantria xylina. [ Method] Three types of representative Casuar/na spp. strains including resistant strains （Zhanjiang 3, Hui 76, Hui 83, Guangdong A8-2）, moderate resistant strains （Pingtan 2, Hui 1, Long 7-18） and susceptible strains （Dongshan 2, Guangdong 501, Kang[eng） were tzst~ as materials to determine the contents of six kinds of inclusions, total phenol, tannin, flavonoids, protein, soluble sugar and polysaccharide. [ Result] The resistant strains had higher flavonaids, tannin and total phenol contents and lower soluble sugar and protein contents than the susceptible strains, while the content of polysaccharide acted randomly. The grey correla- tivity analysis showed that resistance degree, pupation rate and pupal weight had high correlation with protein and soluble sugar contents, with correlation index equal to or above 0.500 0. [ Conclusion] The study provided a theoretical basis for screening and promotion of resistant strains against L xylina.

Seasonal changes in tannin and nitrogen contents of Casuarina equisetifolia branchlets

Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT), and protein precipitation capacity (PPC) in young, mature and senescent branchlets of Casuarina equisetifolia were studied at Chishan Forestry Center of Dongshan County, Fujian Province, China. In addition, nitrogen contents of branchlets at the different developmental stages were also determined. The contents of TP and ECT, and PPC in young branchlets were significantly higher than those in mature and senescent branchlets through the season. However, PBCT contents were significantly higher in senescent branchlets than those in young and mature branchlets; FBCT fluctuated with season. Young branchlets had the highest N content, which decreased during branch maturity and senescence. The highest contents of TP and the lowest contents of TCT and N in young and mature branchlets were observed in summer. There was a significant negative correlation between TP and N contents. In contrast, TCT contents were positively correlated to N contents. Nutrient resorption during senescence and high TCT:N ratios in senescent branchlets are the important nutrient conservation strategies for C. equisetifolia.

Physiological Responses of Mangroves to Flooding and Anaerobic Stress

Flooding and anaerobic stress is one of the stress factors affecting mangroves.Mangrove species,differing considerably in their susceptibility to the stress,are distributed in different tidal elevation zones.Growing in regular seawater dipping and anoxic mud,mangroves have developed a set of adaptation mechanisms of flooding and anaerobic stress.This paper emphatically reviewed four physiological responses of mangroves to flooding and anaerobic stress,i.e.nutrition allocation, photosynthesis and respiration,carbon and nitrogen metabolism and antioxidant mechanism.Finally,it was proposed that studies should be further focused on the path of roots metabolism,non-structure carbohydrates and secondary metabolism of the mangroves under flooding and anaerobic condition.