Aims Plant leaf morphological traits can effectively reflect changes of plant living environments and affect the behaviors and function of plants. Our objective was to reveal the response of leaf morphometric traits of Quercus species to climate in the temperate zone of the North-South Transect of Eastern China (NSTEC).
Methods We obtained leaf morphometric information by measuring plants in herbariums. We used mathematical methods of correlation analysis and standardized major axis to investigate relationships between leaf morphology and climate factors, as well as correlations among leaf morphological traits.
Important findings With changing climate conditions in the temperate zone of NSTEC, leaf morphological traits of Quercus species changed significantly. Leaf area of Quercus species increased with decreased annual temperature and increased annual sunlight, which helps leaves to absorb more light radiation and reduce the loss of heat. The degree of leaf division can not only decrease heat dissipation from leaves, but can also enhance the fluctuation of sap flow to improve the physiological activities of leaves. Vein density increased with increased temperature and light intensity, improving the water transportation capacity, and increased with increased precipitation, improving the supporting ability of leaves. In addition, in order to adapt to the changed climate conditions, Quercus species built a combination of leaf morphological traits, with increased leaf area, petiole length and degree of leaf division, while vein density decreased. Petiole length and vein density also increased with the leaves tending toward an elongated shape.

Aims Increasing sequestration of soil organic carbon with forest succession plays a significant role in reducing global warming. However, the relationship between structure of soil carbon pools and vegetation carbon inputs is still uncertain. Our objective was to examine how structure of the soil carbon pool changes with vegetation carbon return through litterfall, forest floor and fine roots during secondary succession in evergreen broad-leaved forests.
Methods The study site is located in Tiantong National Forest Park (29°52′ N, 121°39′ E), Zhejiang Province, in Eastern China. Three successional stages (i.e., early, middle and late stages) were selected to examine contents and stocks for carbon pools for each of total soil organic carbon (TOC), mineralization carbon (MC), dissolved organic carbon (DOC) and microbial biomass carbon (MBC). The amounts of vegetation carbon return through each of the litterfall, forest floor and fine roots were determined. Then relationships between carbon pool stocks and amount of vegetation carbon return were determined by using both Pearson correlation and stepwise regression approaches.
Important findings Along the forest successional series, contents of TOC, MC, DOC and MBC increased significantly (p < 0.05). Stocks of TOC also increased through forest succession ( p < 0.05), but the other three active organic carbon stocks were highest in middle-, intermediate in late- and lowest in early-successional stages. The amounts of annual biomass and carbon stocks increased for litterfall, but decreased for forest floor, and fine roots annual returned mass and carbon stocks were highest in middle-, intermediate in late- and lowest in early-successional stages ( p < 0.05). Among three active organic carbon pools, MC explained 34.01% variation in TOC ( R²= 0.388, p < 0.05). With respect to vegetation carbon return, returned biomass of fine roots explained 28.2%, 50.0%, 73.4% and 68.8% of total variation for TOC, MC, DOC and MBC, respectively. In conclusion, stocks of TOC and three active organic carbon pools elevate gradually with secondary forest succession in the study area. During this process, the accumulation of fine roots and the enhancement of mineralization carbon pool are mainly responsible for soil carbon sequestration.

Aims Allometric relationship between branch and leaf is limited by plant ontogeny and affected by environmental conditions, which is not well investigated in giant clone species such as Phyllostachys heterocycla‘Pubescens’. Our objectives were to study the effects of different management modes (obtruncation and fertilization) on branch and leaf biomass allocations ofP. heterocycla‘Pubescens’ and to discuss the effects within canopy.
Methods Obtruncation is a particular pruning operation cutting off the top (about 40%-70% canopy) of P. heterocycla‘Pubescens’. This management methods used in north Zhejiang of China to reduce trees falling from strong wind or heavy snow. A replicated 2 × 2 factorial experiment (obtruncation and fertilization) was established in Zhejiang Province in 2004. In 2010 and 2011, a total of 50 plants were cut down to investigate branch and leaf biomass, as well as leaf area of selected leaves within the canopy. Allometric scaling was applied to analyze the relation of branch and leaf biomass.
Important findings Averaged branch and leaf biomass for individual plant were decreased 40.23% and 41.01%, respectively, following obtruncation and increased 20.18% and 30.23%, respectively, following fertilization. Obtruncation severely changed the growth trajectory and resulted in a greater standardized major axis (SMA) slope, which indicated relatively more biomass was allocated to leaves. This was more significant under non-fertilization treatments. When compared to non-fertilization, fertilization significantly decreased SMA slope in unobtruncated trees, which was attributed to relatively larger leaf photosynthetic products partitioning to branches after fertilization. In addition, allocation patterns of branch and leaf biomass at different canopy parts were affected by light availability that was different in different fertilization treatments. Obtruncation changed SMA slope by nearly 50% and <10% for fertilization, which indicated that direct interference (obtruncation) easily changed the grown trajectory and indirect effects (fertilization) were more limited by plant ontogeny.

Aims In this paper, we studied the timing and environmental factors associated with the production of male and female strobili (cones) of Tsuga dumosa using eight populations of reproductive age.
Methods We measured the growth of 24 reproductive plants, and quantified the production of male and female cones at multiple canopy heights and directions using the standard branch method.
Important findings The ratio of female to male cones was 1:2, and only 28% female cones developed seeds. Plants with a 7 cm diameter at breast height (DBH) (about 25 years old) begin producing cones first, while plants with DBH between 25 and 30 cm produced the highest abundance of male and female cones. A plant with a 89 cm DBH (about 200 years old) produced cones latest. There were obvious differences in the distribution of male and female cones at different canopy heights and orientations. Correlation analyses show that there was a significant positive correlation between DBH and cone (male and female) quantity (p < 0.01), and a significant positive correlation between DBH and the size of canopy. There was a negative correlation between canopy density and cone quantity, height, and DBH. The seed yield was significantly negative correlation. Analysis using principal components indicated temperature, water, and light exposure were the main factors affecting cone production. These factors caused population decline in the ratio between female and male cones towards male-biased, and seed bearing period is long and seed bearing way is not economic. Thus, weather conditions aggravated population decline. Artificial regeneration, establishing a seed orchard, and improving the quality of seeds are significant factors in the improvement of seed quality and population restoration.

Aims Our objectives were to determine effects of sand burial on growth and physiological response in psammophytes and to compare differences in abilities and mechanisms of different psammophytes to resist sand burial. We examined changes in survival rate, plant height, osmotic regulation substances contents, protective enzymes activity and membrane permeability of Agriophyllum squarrosumand Artemisia halodendronwith different sand burial depths during 2010 in the Horqin Sand Land of Inner Mongolia.
Methods There were ten sand burial treatments: buried to 0% (CK, no burial) and 25% (A), 50% (B), 75% (C) and 100% (D) of seedling height and 2, 4, 6, 8 and 10 cm above seedlings. Every treatment consisted of four replicates. Stress physiology properties were measured 10-12 days after sand burial, and plant height and survival rate were measured in late August.
Important findings With increased sand burial depth, both survival rate and plant height of Agriophyllum squarrosumand Artemisia halodendron decreased significantly, with a greater decrease in Artemisia halodendron. The maximum depth to resist sand burial exceeded 10 and 8 cm of seedling height for Agriophyllum squarrosumand Artemisia halodendron, respectively. The two psammophytes showed no water stress under sand burial stress. Decreased photosynthetic area and increased difficulties to emerge from the soil were the main factors that inhibited the survival and growth of the psammophyte seedlings. With increased depth of sand burial, malonaldehyde content increased significantly for Agriophyllum squarrosumand decreased significantly for Artemisia halodendron. The increased magnitude of membrane permeability was significantly lower in Artemisia halodendron. Injury of the cell membrane was the main physiological mechanism to decrease survival rate and inhibit growth in the psammophyte seedlings under sand-burial stress. Also, lighter membrane damage was the main physiological mechanism that gaveAgriophyllum squarrosum stronger resistance to sand burial. Although both species reduce plant cell membrane damage and degree of cytoplasm leakage by increasing peroxidase activity and proline content under sand burial stress, superoxide dismutase also showed an important coordinating role for Agriophyllum squarrosumthat makes its enzymatic system more effective in the protection of cell membrane from stress injury.

Aims The objectives were to examine the response of Glycyrrhiza inflatato NaCl stress and understand its salinity tolerance and salt tolerance mechanisms.
Methods By the method of hydroponics, seedlings were cultured in plastic pots filled with a complete Hoagland nutrient solution containing 0, 50, 100, 200 and 300 mmol·L^-1NaCl. After four weeks, we measured the fresh weight, dry weight, water content, shoot height, root diameter, membrane permeability, glycyrrhizic acid, proline, malonaldehyde content and ion content of different parts of the plants.
Important findings Low NaCl concentration had no significant effect on the fresh weight, dry weight and glycyrrhizic acid content of G. inflata seedlings, but ≥200 mmol·L ^-1 NaCl inhibited growth. The optimal salt range for seedling growth was 0-278.17 mmol·L^-1, which was calculated by the fitting equation for the relationship between salt tolerance index and salt concentration. With increasing NaCl concentration, the uptake of K⁺, Ca²⁺and Mg²⁺by plants from outside a salt environment significantly increased, whereas the Na⁺ uptake was inhibited. For the 0-100 mmol·L^-1concentration of NaCl, the preferential accumulation of Na⁺ in roots over leaves can be interpreted as a mechanism of tolerance. For concentrations of 200 mmol·L^-1 and above, most Na⁺ was transported to the lower leaves and then disposed through leaf fall, exhibiting salt efflux behavior of the seedling. Under salt stress, the transport systems selective for K⁺were functioning. Thus the upper leaves maintained a high K⁺/Na⁺ ratio that was beneficial to the growth of seedlings. In addition, the salt-tolerant root accumulated Ca²⁺and Mg²⁺ as well as synthesized glycyrrhizic acid and proline to increase osmoregulation ability, maintain cell membrane stability and reduce Na⁺ toxicity. These are the ways that G. inflata seedlings are adaptive to a saline environment.

Aims Shell ridge islands are distinctive shell sand deposits lying on the upper surface of tidal flats where shellfish grow in abundance and fresh water discharge is minimal. The objective was to elucidate the critical effect of photosynthetic efficiency parameters in leaves of Salix matsudana on soil moisture, clarify the threshold range of photosynthetic efficiency to soil moisture, and define the water adaptability in shell ridge islands of Shandong Province, China, in the middle of the Yellow River Delta.
Methods Two-year-old S. matsudana grown on shell ridge islands was selected as the experimental material. Soil water gradients were obtained by providing water and by natural water consumption. ACIRAS-2 portable photosynthesis system was used to measure the photosynthetic efficiency parameters under different soil water conditions. The light response curves of net photosynthetic rate (P_n) and the water response curves of gas exchange parameters in leaves of S. matsudana were fitted and analyzed.
Important findings The P_n, transpiration rate (T_r), water use efficiency (WUE) and photosynthetic parameters of light response in leaves ofS. matsudana had significant critical effects on soil moisture. P_n, T_r, WUEand intrinsic water use efficiency first increased and then decreased with decreasing soil water, but their critical values were different. The critical value of relative soil water content (W_r) from stomatal limitation to non-stomatal limitation of P_n was 42.9%, and the water compensation point of P_n was 14.4%. The water saturation points of P_n and T_rwere 73.1% and 68.9%, respectively, and the water efficiency point of WUE was 80.1%. Salix matsudana appeared to have photo inhibition under drought stress and had the physiological strategy of weakening light utilization to counter stress. With increasing soil water, the apparent quantum yield (AQY), light saturation point (LSP) and maximum net photosynthetic rate (P_nmax) first increased and then decreased, while the light compensation point (LCP) first decreased and then increased. The values of P_n, AQY, LSP, P_nmax and dark respiration rate (R_d) under water logging stress were higher than under drought stress. When W_r was 69.1%, LCPreached a lower value with 18.6 µmol∙m ^-2∙s^-1, and AQY reached a higher value with 0.05, indicating that S. matsudana had strong ability to utilize weak light. When W_r was 80.9%, LSP reached the highest point with 18.6 µmol∙m ^-2∙s^-1, indicating that S. matsudana had wide light ecological amplitude and high light utilization efficiency. The compensatory effect on light intensity of soil water was significant. The soil water content was divided into five threshold grades by critical values to maintain photosynthetic efficiency of S. matsudana at different levels in shell sand soil. W_r of 73.1% to 80.1% was classified as high productivity and high efficiency; in this range, S. matsudana had high photosynthetic capacity and efficient physiological characteristics for water consumption. In conclusion, S. matsudana had the typical characteristics of water tolerance and no drought stress in shell sand, thus plantings should give full consideration to the soil water environment in shell ridge island.

Aims Our objective is to study the change rules of the main phytolith morphotypes in Phragmites australis from June to October.
Methods We selected similarly sized leaves of P. australis in 12 sampling sites and extracted phytoliths with the wet-ashing method.
Important findings The main phytolith morphotypes in P. australis could be classified into five categories. There is little change about the phytolith assemblages in P. australis during different growth periods and different combination of temperature and humidity. This implies that phytolith morphotypes of the same plant species are stable and therefore can be used to effectively reconstruct paleo-vegetation. The maximum value of the saddle percentage appears in July and then slightly decreases. While the maximum value of the percentage and concentration of the bulliform appears in August or September, with its minimum value in July. This indicates that the saddle formation may be more controlled by plant photosynthesis and transpiration, while the bulliform formation may be closely associated with the support of bulliform cells. The result also shows that the phytolith concentration in P. australis does not gradually accumulate from June to October. Its maximum value appears in August and its minimum value in September, so the change rules of the phytolith concentration may be concordant with the need of silicon for plants in different growth periods. Furthermore, the maximum value of the saddle concentration in P. australis also appears in August, with its minimum value in September. This trend is similar to changes of the phytolith concentration in P. australis.

The science of protective forest includes the theories and technologies of creating and managing (using, conserving, repairing and renewing) protective forests in a sustainable manner to meet the desired goals, needs, and values for human benefits. This science is practiced in both plantations and natural stands. Its major goal is to create and manage protective forests to continue a sustainable benefit of protection for the objectives needed to be protected. The development of this science mostly depends on the requirements from the creation of protective forests because it is a related science involving the practice of growing and tending trees and the protective forests. It is an applied art and a technology. The worldwide national-level ecological engineering projects, such as the Great Plains Shelterbelt Project (Roosevelt Engineering) in USA, the Great Plan for the Transformation of Nature in the former Soviet Union, the forestry and water conservation projects in Japan and the Green Dam Engineering Project in the five countries of North Africa, promoted the development of the science of protective forest. The major advances in the science included planning and design, tree species selection, spatial arrangement, planting technologies, structure modeling, thinning and tending, decline and regeneration and benefit assessment. There is much more literature on benefit assessment than other aspects. In China, many areas are influenced by desertification, soil and water loss and windy climate, so protective forests have been created widely, especially the Three North Protective Forest Program (the Green Great Wall) initiated in the west of Northeast China, the north of North China and Northwest China. Therefore, the science of protective forest has developed greatly as well, especially with significant contributions to management theory and techniques. The science of protective forest generally contains a broad range of concerns on the theories and technologies in creating and managing protective forests, which are linked by the benefit assessment. In fact, all forests, particularly non-commercial forests have protective functions. The methods of studying protective forests range from the stand scale to more microcosmic and to more macroscopic scales. With regard to creation of protective forests, studies should be done on planning and design according to regional differentiation characteristics on the basis of ecosystem stability and landscape ecology. For managing protective forests, studies should include the decline mechanism, the near-natural management and the assessment of protective forests. Benefit assessment of protective forests will be conducted at a large scale with remote sensing technology.

Selection on defense strategies of plant species may be different in direction and magnitude among sites, because of differences in the herbivore communities in which plant populations are embedded. This may be the case for some invasive species, which are often introduced without coevolved specialists, but suffer generalist damage comparable to their native ones. We review recent advances in the adaptive evolution of defense strategies in Chinese tallow (Triadica sebifera) and other invasive plant species. We focus particularly on resistance and tolerance, direct and indirect resistance, and constitutive and induced resistance to understanding the effects of herbivores on invasive plant success. Furthermore, we evaluate the effects of changes in defense strategies on the efficiency of biological control. We also propose future research on defense strategies of invasive plant species.