Insects in the order Hymenoptera defend themselves, attack prey and regulate hosts using toxins that are effective in small quantities. In this study, advances in the researches on parasitic hymenopteran toxins are summarized in terms of the production, categories, components, properties, ecological functions and mechanisms. The glands that produce venoms derive from the ectoderm tissue and evolve from the accessory glands of the reproductive system. Venoms are excreted by the poison gland or acid gland of mature female wasps and stored in reservoirs. The components of insect toxins are very complicated, and hymenopteran venoms contain alkanes, alcohols, aldehydes, ketones, organic acids, esters, lactones, proteins, polypeptides, enzymes, amines and other compounds. Toxins of parasitic hymenoptera play an important adaptive role. They can increase the probability of successful oviposition by paralyzing hosts, enhancing offspring survival by inhibiting host development and immunoreaction, and improving the nutrition available for their progeny by disturbing the hosts’ physiological response. Venoms of the ectoparasitoids often lead to arrested development, permanent paralysis and even death of hosts. These toxins are usually broad-spectrum and act on the central nervous system or at the neuro-muscular junction. While most endoparasitoids are koinobionts, these parasitoids can regulate the physiology and development of the hosts, but no longer paralyze the hosts permanently. Also, they kill the hosts in a concealed but safe position after the hosts cocoon or build their pupal cells. Venoms of koinobiont parasitoids can contain polydnaviruses (PDV) that regulate the growth and development of the hosts by inhibiting the immune system and influencing the metamorphosis of hosts. Thus, PDVs are commensal and mutualistic, but non-pathogenic, with parasitoids at the molecular level. Promising prospects for the utilization of insect toxins, especially as medicines or specific bioinsecticides, are discussed. Because insect toxins are mixtures of complex ingredients and are usually produced in small quantities, isolation and purification of all the ingredients with bioactivity are needed for biochemical and toxicological research and for practical application.

Many textural measures have been developed and used for improving land cover classification accuracy, but they rarely examined the role of textures in improving the performance of forest aboveground biomass estimations. The relationship between texture and biomass is poorly understood. In this paper, SPOT5 HRG datasets were ortho-rectified and atmospherically calibrated. Then the transform of spectral features is introduced, and the extraction of textural measures based on the Gray Level Co-occurrence Matrix is also implemented in accordance with four different directions (0°, 45°, 90° and 135°) and various moving window sizes, ranging from 3 × 3 to 51 × 51. Thus, a variety of textures were generated. Combined with derived topographic features, the forest aboveground biomass estimation models for five predominant forest types in the scenic spot of the Mausoleum of Sun Yat-Sen, Nanjing, are identified and constructed, and the estimation accuracies exhibited by these models are also validated and evaluated respectively. The results indicate that: 1) Most textures are weakly correlated with forest biomass, but minority textural measures such as ME, CR and VA play a significantly effective and critical role in estimating forest biomass; 2) The textures of coniferous forest appear preferable to those of broad-leaved forest and mixed forest in representing the spatial configurations of forests; and 3) Among the topographic features including slope, aspect and elevation, aspect has the lowest correlation with the biomass of a forest in this study.

Regressive models of the aboveground biomass for three conifers in subtropical China-slash pine (Pinus elliottii), Masson pine (P. massoniana) and Chinese fir (Cunninghamia lanceolata)-were established. Regression analysis of leaf biomass and total biomass of each branch against branch diameter (d), branch length (L), d³ and d²L was conducted with functions of linear, power and exponent. A power law equation with a single parameter (d) was proved to be better than the rest for Masson pine and Chinese fir, and a linear equation with parameter (d³) is better for slash pine. The canopy biomass was derived by adopting the regression equations to all branches of each individual tree. These kinds of equations were also used to fit the relationship between total tree biomass, branch biomass, foliage biomass and tree diameter at breast height (D), tree height (H), D³ and D²H, respectively. D²H was found to be the best parameter for estimating total biomass. However, for foliage biomass and branch biomass, both parameters and equation forms showed some differences among species. Correlations were highly significant (P < 0.001) for foliage biomass, branch biomass and total biomass, among which the equation of the total biomass was the highest. With these equations, the aboveground biomass of Masson pine forest, slash pine forest and Chinese fir forest were estimated, in addition to the allocation of aboveground biomass. The aboveground biomass of Masson pine forest, slash pine forest and Chinese fir forest was 83.6, 72.1 and 59 t/hm² respectively, and the stem biomass was more than the foliage biomass and the branch biomass. The underground biomass of these three forests which estimated with others’ research were 10.44, 9.42 and 11.48 t/hm², and the amount of carbon-fixed were 47.94, 45.14 and 37.52 t/hm², respectively.

To discover the site adaptability and density suitability of Larix principis-rupprechtii as a water conservation forest in Wutai Mountain, Shanxi Province, the growth process and diameter distribution characteristics of 10-year-old artificial L. principis-rupprechtii forests with density structures of 2600 trees/hm² and 3500 trees/hm² were studied using trunk analysis of a sample tree. The results showed that: 1) The tree height increment of the two kinds of forests were the same, and it was almost not affected by density. However, the growth process of the diameter and timber volume showed a great distinction. The growth status and density structure of the low density forest were superior to the high density forest. 2) The skewness (S_k) of diameter distribution had great distinction. The S_k (0.01) of the low density forest approached a normal distribution, which showed that the density structure was reasonable, while the S_k (0.45) of the high density forest was partial to a normal distribution, which showed that the density structure was on the high side. The kurtosis (K) of the two forests (one was -0.64, the other was -0.74) had little distinction and the density factor had limited function to forest polarization. 3) The increment of diameter at breast height, timber volume and trunk stock of the low density forest increased yearly without the effect of density. However, the increment of high density forests had declined from the sixth year, which was restricted by high density. 4) The reasonable density of the 10-year-old L. principis-rupprechtii artificial forest was about 2600 trees/hm², which is also the reasonable planting density if the utilization of double cutting is not considered.

In the semi-arid Horqin sandy land of north China, Caragana microphylla, a leguminous shrub, is the dominant plant species and is widely used in vegetation reestablishment programs to stabilize shifting sand. The sand-fixing effects of 6- and 11-year-old C. microphylla plantations were studied. The results showed that: 1) the wind velocity and sand transport rate in the plantation were less than those in dunes; 2) the air temperature in the plantation was lower than those in dunes. Relative humidity was higher and the soil temperature was lower, which benefits plant growth; 3) the physical and chemical characteristics of soil were improved to some extent over age. The porosity and percentage of tiny sand (diameter 0.05–0.1 mm) and clay particle (diameter < 0.05 mm) increased, bulk density in surface soil decreased, and saturated water-holding capacity improved. Organic C, total N, available N and available K content increased gradually, and soil fertility was enhanced.

Historical forest fire records from Alaska State (1950–2000), California State (1895–2001), USA and Heilongjiang Province (1980–1999), China were used to calculate the longitude and latitude of the annual burned area’s centroids for these regions. Fluctuation phenomena by year were analyzed using spectrum analysis. The results show that centroids of burned areas in these three regions are in a fluctuating condition that encircles the distribution center. The distribution centers are 151.11°W, 64.96°N in Alaska State, 120.02°W, 37.11°N in California State and 127.07°E, 49.59°N in Heilongjiang Province, respectively. The fluctuation of the burned area’s centroids in Alaska State and California State in longitude has obvious periodicity, and the periodicities are 4.2 years, 6.25 years in Alaska State and 6.24 years, 106 years in California State. The fluctuation of the burned area’s centroids in Heilongjiang Province has a periodicity both in longitude and latitude, and the periodicities are both 3.3 years, 6.67 years. Fluctuation of the burned area’s centroids in Alaska State and California State in latitude does not have periodicity, and big forest fires with low frequencies predominate.

Water is the key factor in vegetation growth in a loess area. Researchers have been keen on the study of tree transpiration for a long time. To provide a scientific basis and practical instruction for vegetation reconstruction and recovery in a loess area, the paper measured and calculated the water consumption of potted Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis separately during the growing season (from Apr. to Nov.). The four were the main afforestation species in a loess area of western Shanxi based on the principle of water balance. Using data on soil water dynamics and the range of available moisture on potted mature trees, the relationship between water supply and consumption and soil moisture availability and deficit state were analyzed. Several conclusions are listed as follows: 1) In the dry year (2002), during the growing season the precipitation was 430.7 mm and the water consumption of potted trees was from 430 to 490 mm. More water consumption and less available water supply occurred, showing a serious water deficiency. In the rainfall-rich year (2003), during the growing season the precipitation was 870.2 mm and the water consumption of potted trees was from 480 to 515 mm. Due to the uneven distribution of rainfall, the water budget balance was slightly affected in May and November. 2) The curves of soil water content of different species had similar annual changes, although the trends were different in the same month, and those of the same tree species in different test plots also had different trends in the same month. 3) Non-available soil water content of Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis was less than 8.0%, 8.4%, 9.2% and 9.7% respectively, which indicated that Pyrus orentalis used water more efficiently than the others. In the dry year (2002), for several months, soil water content of potted trees was lower than its threshold value for non-available soil water content, which could influence the healthy growth of trees. After supplements of precipitation of winter in the year and spring in the next year, soil water content was higher than the lower limit of soil readily available moisture content, which implied that a balance between inter-annual water supply and consumption could be maintained.

The process of rainfall interception by an inhomogeneous forest canopy composed of tree crowns with some gaps among them were considered, and the previous theoretical models of rainfall interception were modified to model an inhomogeneous canopy instead of a statistically homogeneous canopy. The paper deals with the following. First, the process of rainfall interception in tree crowns and that of rainfall in the gaps among them are studied respectively to acquire the average rainfall interception of a forest canopy. Based on the model derived by Liu (1987) and setting the canopy density value, both the relevant partial equations and a formula to estimate rainfall interception were derived. Moreover, the new model was solved through a numerical method and was illustrated with typical values of some ecological factors; three groups of curves were acquired by calculation with the VisualBasic program. A model of rainfall interception by an inhomogeneous forest canopy is classified as a multi-layer model, which is different from previous models (models where all the parameters represent the whole canopy). The results from the model in this paper could be used to determine the relationship between interception and each ecological factor in detail.

The characteristics and actualities of ecological public welfare forests in South China are studied in this paper, including common and special management patterns. The restoration and reconstruction pattern of subtropical evergreen broad-leaved forests, zonal vegetation in the key eco-zone, and the transformation pattern of coniferous and broad-leaved mixed forests in the general eco-zone with multi-forms are discussed in detail. The authors also point out, based on ecological transformation and utilization, that ecological public welfare forests should be oriented to multiple benefit utilization to maintain sustainable management.

Granier’s probes were applied to measure the sap flow of 14 sample trees in an Acacia mangium forest on the hilly lands in Heshan City, Guangdong, during the time period of October, 2003. The photosynthetically active radiation (PAR), air relative humidity (RH) and temperature of air (T) above the forest canopy were recorded. The sap flow measurement was used in combination with morphological characteristics of tree and forest structure to calculate the whole-tree transpiration (E), stand transpiration (E_t), and mean canopy stomatal conductance (g_c). Analyses on the relationships between tree morphological characters and whole-tree water use, and on the responses of g_c to PAR and vapor pressure deficit (D) were conducted. The results showed that whole-tree transpiration correlated significantly and positively with tree diameter at breast height (DBH) (p < 0.0001), with sapwood area (p < 0.0001), and with canopy size (p = 0.0007) logarithmically, but exponentially with tree height (p = 0.014). The analyses on the responses of canopy stomatal conductance showed that the maximum g_c (g_cmax) changed with PAR in a hyperbolic curve (p < 0.0001) and with D in a logarithmic one (p < 0.0001). The results obtained with sap flow technique indicate its reliability and accuracy of the methods of estimation of whole-tree and stand transpirations and canopy stomatal conductance.

In this paper, we studied the nocturnal stem water recharge of Acacia mangium. It is helpful to improve the precision of canopy transpiration estimation and canopy stomatal conductance, and to further understand the lag time of canopy transpiration to stem sap flow. In this study, the whole-tree sap flow in an A. mangium forest was measured by using Granier’s thermal dissipation probe for over two years in the hilly land of South China. The environmental factors, including relative humidity (RH), precipitation, vapor pressure deficit (VPD), photosynthetically active radiation (PAR), and air temperature (T_a) were recorded simultaneously. The stem water recharge of A. mangium was analyzed on both daily and monthly scales. Sap flux density was lower at night than during the day. The time range of nighttime sap flux density was longer in the dry season than in the wet season. The water recharging mainly occurred from sunset to midnight. No significant differences were observed among inter-annual nighttime water recharges. Nighttime water recharge had no significant correlation with environmental factors, but was well correlated with the diameter at breast height, tree height, and crown size. In the dry season the contribution of nighttime water recharge to total transpiration had significant correlations with daytime transpiration, total transpiration, VPD, PAR and T_a, while in the wet season it was significantly correlated with daily transpiration and total transpiration.

In this paper, based on a long-term monitoring of water cycle in the water and soil conservation forest stands of Pinus tabulaeformis and Robinia pseudoacacia, the soil moisture deficit is calculated. Following the principles of runoff-collecting forestry and applying the forest structure investigation results, the authors developed a formula to calculate appropriate density for forests on the basis of different diameters at breast height (DBH). Using this method to manage forests, the natural water requirement of forests can be met and soil drought can be avoided. In addition, with long-term monitoring of soil moisture in stands, the authors also give an appropriate managing density specifically for the water and soil conservation forests of P. tabulaeformis and R. pseudoacacia in the loess area which is according to soil moisture content, or with the lowest soil moisture content and invalid moisture frequency as the indexes.

A group of scientists conducted a comprehensive investigation on ecological safety and water and soil erosion in the Northwest Loess Plateau, Northwest China. The data gathered was analyzed in terms of achievement, existing problems, and strategy and measures on vegetation restoration in the area. Since the policies of conversion from cropland to forest (CCF) and forbid grazing and cutting (FGC) were carried out, vegetation quality and coverage rate increased quickly in the Loess Plateau area, strengthening the concept of eco-environment protection. Environment harness measurements were optimized. The multiform investments on eco-environment and urbanization development in China will benefit vegetation restoration. However, there have been some persisting problems, such as the shortage of investment, instability of government policy, expectation of extravagant economic benefit, larger rate of plantation, and scarce technologies supporting vegetation restoration. Many key theories and practice problems require an urgent resolution. In the future, short-, mid-, and long-term goals for vegetation restoration should be clear, achievement should be expanded, and the natural restoration area should be increased. The benefit for the contractor on vegetation restoration should be ensured. Investment on vegetation building research work should be increased.

The characteristics of the eco-environment, extension scale and sustainable models of converting cropland to forest in the Dabieshan District of Anhui were analyzed. The Dabieshan District is a main ecological area with a function of soil and water conservation where seven large reservoirs and irrigation systems of the Pishihang are distributed. Therefore, the extension scale of converting cropland to forest could be enlarged properly in the reservoir area, while it should be limited in the non-reservoir area due to the issues of higher population density and food safety. Great attention should be paid to the model selection and results during the conversion of cropland to forest. Some suitable models and effective approaches were put forward for the sustainable development in the Dabieshan District, Anhui.

The characteristics of root growth in the fast-growing and high-yield plantation of poplar I-214 (Populus × euramericana cv. ‘I-214’) were studied under two contrasting conditions, subsurface drip-irrigation (SDI) and normal irrigation (CK), on the sandy soil of Chaobai River, Beijing. The results showed that in the soil layer of 20–50 cm, there was a considerable increase in the amount of roots less than 10 mm in diameter (especially those of less than 2mm) under SDI, which was three times as much as that under CK. The absorbing roots under SDI were concentrated in the soil layer of 20–50 cm, while the roots under CK were distributed evenly in each layer. With respect to horizontal distribution, roots (d < 10 mm) under SDI were distributed mainly near the subsurface emitters and the amount of roots in 3 m in a row under SDI were 50% less than under CK. Therefore, it is suggested that subsurface emitters with the shape of “#” should be collocated in the middle of two rows and two individual trees to increase the distributing and absorbing range of roots under SDI, and further increase the plantation productivity.

By using random amplified polymorphic DNA (RAPD) technique, this paper studied the genetic diversity and genetic differentiation of Lithocarpus harlandii populations in three forest communities (coniferous forest, coniferous and broad-leaved mixed forest, and evergreen broad-leaved forest) with different succession stages in Tiantai Mountain in Zhejiang Province. The results showed that a total of 173 repetitive loci were produced in 60 individuals of L. harlandii by 12 random primers, among which, 152 loci were polymorphic, and the total percentage of polymorphic loci was 87.86%. The average percentage of polymorphic loci of the populations was 65.32%, and their total genetic diversity estimated by Shannon information index was 0.4529, with an average of 0.3458, while that judged from Nei’s index was 0.3004, with an average of 0.2320. The percentage of polymorphic loci, Shannon information index, and Nei’s index of the populations were in the sequence of coniferous forest community > coniferous and broad-leaved mixed forest community > evergreen broad-leaved forest community. Analysis of molecular variance (AMOVA) showed that 72.85% of genetic variance was found within the populations, and 27.15% of genetic variance resided among the populations. The coefficient of gene differentiation was 0.2277, and the gene flow was 1.6949. The genetic structure of L. harlandii was influenced not only by the biological characteristics of this species, but also by the microenvironment of different communities. The mean of genetic identity among three populations of L. harlandii was 0.8662, and the mean of their genetic distance was 0.1442. The genetic similarity between coniferous and broad-leaved mixed forest community and evergreen broad-leaved forest community was the highest, while that between evergreen broad-leaved forest community and coniferous forest community was the lowest. The unweighted pair group method with arithmeticmean (UPGMA) cluster analysis based on Nei’s genetic distance showed that coniferous and broad-leaved mixed forest community first gathered with evergreen broad-leaved forest community, and then with coniferous forest community.

Simultaneous introduction of multiple genes into plants is a critical step in plant genetic engineering to manipulate multiple functional genes in metabolic engineering and trait stacking. It is important to construct a bidirectional promoter for transforming two or more genes into plants simultaneously. The widely used unidirectional CaMV35S promoter has been modified to a bidirectional promoter in this work by fusing a CaMV35S minimal promoter (Pmini) at its end in opposite orientation to the original promoter. To test its bi-directional transcriptional activities, two widely used histochemically visible reporter genes, gusA (?-glucuronidase) from Escherichia coli and gfp (Green Fluorescent Protein) from Aequorea victoria, were fused to the terminus of the bidirectional promoter in different orientations ending with NOS terminator sequences. The transient expression of the gusA and gfp genes were detected by histochemical staining for GUS and by fluorescence microscopy for GFP. The direction of transient expression of GUS and GFP in Agrobacterium mediated 3–4 days transformed leaf discs of Populus tomentosa, indicating that the promoter did have bidirectional transcriptional activities simultaneously in cells and tissues. It was discussed that this bidirectional promoter could possibly be applied in woody plant engineering.

Organic acid exudation from the roots of Chinese fir (Cunninghamia lanceolata) and Masson pine (Pinus massoniana) seedlings under low phosphorus stress was studied using the solution culture method. The results revealed that organic acid exudation from the roots of Chinese fir and Masson pine seedlings under low phosphorus stress increased. Compared with P₃ (KH₂PO₄, 0.5 mmol/L), the average organic acid exudation from the root of Masson pine seedlings under P₀ (KH₂PO₄, 0 mmol/L), P₁ (KH₂PO₄, 0.03 mmol/L) and P₂ (KH₂PO₄, 0.09 mmol/L) increased by 328.6%, 267.9% and 126.4% respectively. Masson pine from Zhejiang Province in China had the highest organic acid exudation. Under low phosphorus stress, the increase in organic acid exudation from the different provinces of Chinese fir and Masson pine varied. Masson pine from Zhejiang Province mainly increased oxalic acid, tartaric acid, citric acid and malic acid exudation, that from Guangxi Province mainly increased oxalic acid and tartaric acid exudation, and that from Guizhou Province, China mainly increased oxalic acid, tartaric acid and malic acid exudation. Chinese fir mainly increased oxalic acid and tartaric acid exudation.

With water-soluble phenol-formaldehyde resin as an intermediate, Chinese fir (Cunninghamia lanceolata) wood/montmorillonite nanocomposite (WMNC) was prepared through vacuum impregnation and characterized with XRD, SEM, FTIR and TG-DTA analyses. The XRD analysis indicated that the wood crystallinity of WMNC decreased, the MMT exfoliated and some nano silicate layers entered into the non-crystallized microfibrillar region of the wood cell wall. Wood structure is anisotropic and its impregnation is anisotropic. Due to the nonuniformity of the MMT organic modification, PF intercalation and wood impregnation, the MMT configuration and distribution in wood were diverse. The SEM graphs of WMNC showed that some silicate grains were blocked in the wood cell lumen, some silicate layers adhered to the inner surface of the wood cell wall, and some exfoliated MMT layers even penetrated the wood cell wall. The obtained hydroxyl of WMNC increased and its ether linking decreased. It was considered that MMT and wood interacted not only with hydroxyl bonds, but also involved some chemical linking. Compared with untreated wood and the PF-impreg, the pyrolysis process of WMNC changed; its starting decomposing temperature decreased and its pyrolysis weight loss at high temperatures greatly decreased. The WMNC indicated certain nanoeffects of the composition of the inorganic MMT nanolamellae.

This research investigated the variation in tensile properties and the relationship between the tensile properties and the air-dried density for the moso bamboo (Phyllostachys pubescens) by sampling at different heights and radial positions. Results showed that the variation of the longitudinal tensile properties in the radial direction was greater than that in the longitudinal direction. The longitudinal tensile modules of elasticity (MOE) ranged from 8.49 to 32.49 GPa. MOE for the outermost layer was 3–4 times as high as that for the innermost layer. The longitudinal tensile strength (MOR) ranged from 115.94 to 328.15 MPa. MOR for the outermost layer is 2–3 times as high as that for the innermost layer. Linear and curvilinear regressions were done from tested data of MOE, MOR and air-dried density in this paper. The linear equation worked a little better than the curvilinear one to predict the longitudinal MOR and MOE from air-dried density.