[Show abstract][Hide abstract] ABSTRACT: Background and aims
Anthropogenic nitrogen (N) and phosphorus (P) input has changed the relative importance of nutrient elements. This study aimed to examine the effects of different nutrient conditions on the interaction between exotic and native plants.
We conducted a greenhouse experiment with a native species Quercus acutissima Carr. and an exotic species Rhus typhina L. grown in monocultures or mixtures, under three N:P ratios (5, 15 and 45 corresponding to N-limited, basic N and P supply and P-limited conditions, respectively). After 12 weeks of treatment, traits related to biomass allocation, leaf physiology and nutrient absorption were determined.
R. typhina was dominant under competition, with a high capacity for carbon assimilation and nutrient absorption, and the dominance was unaffected by increasing N:P ratios. R. typhina invested more photosynthate in leaves and more nutrients in the photosynthetic apparatus, enabling high biomass production. Q. acutissima invested more photosynthate in roots and more nutrients in leaf persistence at the expense of reduced carbon assimilation capacity.
Different trade-offs in biomass and nutrient allocation of the two species is an important reason for their distinct performances under competition and helps R. typhina to maintain dominance under different nutrient conditions.
[Show abstract][Hide abstract] ABSTRACT: Water is a main factor limiting plant growth. Integrative responses of leaf traits and whole plant growth to drought will
provide implications to vegetation restoration. This study investigated the drought responses of Vitex negundo L. var. heterophylla (Franch.) Rehd. with a focus on leaf morphology and physiology, seedling growth and biomass partitioning. Potted 1-year-old
seedlings were subjected to four water supply regimes [75, 55, 35 and 15% field capacity (FC)], served as control, mild water
stress, moderate water stress and severe water stress. Leaf morphological traits varied to reduce the distance of water transfer
under water stress and leaflets were dispersed with drought. Net photosynthetic rate decreased significantly under water stress:
stomatal closure was the dominant limitation at mild and moderate drought, while metabolic impairment was dominant at severe
drought. The physiological impairment at severe drought could also be detected from the relative lower water use efficiency
and non-photochemical quenching to moderate water stress. Total biomass of well-watered plants was more than twice that at
moderate water deficit and nearly ten times that at severe water deficit. In summary, V. negundo var. heterophylla had adaptation mechanism to water deficit even in the most serious condition, but different strategies were adopted. Seedlings
invested more photosynthate to roots at mild and moderate drought while more photosynthate to leaves at severe drought. A
nearly stagnant seedling growth and a sharp decline of total biomass were the survival strategy at severe water stress, which
was not favorable to vegetation restoration. Water supply above 15% FC is recommended for the seedlings to vegetation restoration.
KeywordsChlorophyll fluorescence-Cut-leaf chaste tree-Leaf traits-Photosynthesis-Relative growth rate-Vegetation restoration
Acta Physiologiae Plantarum 09/2010; 32(5):839-848. · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Leaf morphological, physiological and biochemical characteristics of Robinia pseudoacacia L. seedlings were studied under different stress conditions. The plants were subjected to drought and shade stress for one
month. Leaf inclination, chlorophyll fluorescence and chlorophyll content were measured at the first day (short-term stress)
and at the end of the stress period (long-term stress) and in the recovery period. Leaf inclination was affected mainly by
light; a low level of irradiance caused leaves to be arranged horizontally. Diurnal rhythmicity was lost after the long-term
stress, but resumed, in part, in the recovery period. Drought stress caused leaves to tilt more obviously and decreased damage
to the photosystem. Sun avoiding movement in a single leaf and sun tracking movement in the whole plant coexisted. Significant
physiological changes occurred under different conditions of light. Increased energy dissipation and light capture were the
main responses to high and low level of irradiance, respectively, and these were reflected by changes of chlorophyll fluorescence
and chlorophyll content. Phenotypic plasticity in the leaflet enhanced the protective response to stress. These adaptive mechanisms
may explain better survival of R. pseudoacacia seedlings in the understory, especially during the drought periods, and made it to be the preponderant reforestation species
in Shandong Province of China.
Acta Physiologiae Plantarum 05/2009; 31(3):553-563. · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This paper presents a case study on structure design and establishment of database application system for alien species in
Shandong Province, integrating with Geographic Information System, computer network, and database technology to the research
of alien species. The modules of alien species database, including classified data input, statistics and analysis, species
pictures and distribution maps, and out date input, were approached by Visual Studio.net 2003 and Microsoft SQL server 2000.
The alien species information contains the information of classification, species distinction characteristics, biological
characteristics, original area, distribution area, the entering fashion and route, invasion time, invasion reason, interaction
with the endemic species, growth state, danger state and spatial information, i.e. distribution map. Based on the above bases,
several models including application, checking, modifying, printing, adding and returning models were developed. Furthermore,
through the establishment of index tables and index maps, we can also spatially query the data like picture, text and GIS
map data. This research established the technological platform of sharing information about scientific resource of alien species
in Shandong Province, offering the basis for the dynamic inquiry of alien species, the warning technology of prevention and
the fast reaction system. The database application system possessed the principles of good practicability, friendly user interface
and convenient usage. It can supply full and accurate information inquiry services of alien species for the users and provide
functions of dynamically managing the database for the administrator.
Journal of Forestry Research 03/2007; 18(1):11-16.
[Show abstract][Hide abstract] ABSTRACT: Light and soil moisture availability are two important abiotic factors influencing plant growth in an agroforestry system. Different soil moisture and light treatments were applied to examine the combined impact of drought and shade on the morphological plasticity of Vitex negundo var. heterophylla (Chinese chastetree) and Ziziphus jujuba var. spinosa (Spine jujube). We found that the interaction of light and soil moisture was orthogonal in the two species. V. negundo captured irradiance efficiently with relatively long petiole and petiolule, while Z. jujuba maintained higher branches to absorb light than V. negundo. Compared to the seedlings under full sunlight, the palmately compound leaves of V. negundo under low light showed larger specific leaf area (SLA), lower ratio of leaflet length to width and higher leaf mass ratio (leaf biomass to total biomass); in contrast, the simple leaves of Z. jujuba under low light showed larger SLA and ratio of leaf length to petiole length. In both species, drought reduced the branch number, mean internode length of stem, and increased root mass ratio (root biomass to total biomass), but leaf morphology showed little variation to the decreased soil moisture. Between the two species, V. negundo is more shade-tolerant, while Z. jujuba is more drought-tolerant. In an alley cropping system, the spacing can be smaller in the V. negundo-crop system than the Z. jujuba-crop system when soil moisture is adequate. However, the V. negundo-crop system should be managed with more caution under the soil moisture limited conditions.
[Show abstract][Hide abstract] ABSTRACT: Competition plays an important role in the replacement of native species by alien plants. A greenhouse experiment was conducted to investigate whether the competition pattern of alien Robinia pseudoacacia L. and native Quercus acutissima Carr. is affected by soil sterilization. Physiological traits, such as gas-exchange parameters and chlorophyll (Chl) content, and growth traits, such as the biomass accumulation of the two species, were examined in natural soil or in soil sterilized with benomyl. The results show that native Q. acutissima inhibits the growth of R. pseudoacacia in natural soil. When the two plants coexisted and competed under sterilization treatment, R. pseudoacacia was less inhibited by Q. acutissima and the competition of R. pseudoacacia decreased the growth of Q. acutissima in terms of biomass, Chl a, Chl b, total Chl, and Chl a/b. These results suggest that soil sterilization benefits the growth of R. pseudoacacia and changes the competition pattern by the changed soil biota. Soil sterilization increased the biomass of root nodules, which ultimately benefits the growth of R. pseudoacacia and root nodule bacteria may be important in the dispersal and invasion process of nitrogen-fixing alien plants such as R. pseudoacacia.
[Show abstract][Hide abstract] ABSTRACT: Acer buergerianum Miq. (Trident maple) is a native species of China with a large distribution, but exist in small population. Water and light are two important factors limiting plant growth and are crucial in the framework of forest regeneration. However, there is no consensus on how shade interacts with drought. Four hypotheses in the recent literature variously predict that shade will have a stronger, weaker or equal impact on seedlings under drought stress. This study investigated the interactive responses of A. buergerianum to light and water focusing on seedling growth, leaf morphology and biomass partitioning by performing a growth experiment in pots with different water supply regimes [15, 35, 55, 75, 95 % of field capacity (FC)] combined with two light regimes (10 and 66 % of full sunlight). After 123 days treatment, the results showed that shade greatly reduced growth and biomass, in contrast enhancing the amount of chlorophyll, the amount of water in the leaves, and the specific leaf area. Drought reduced growth, biomass, and the bulk of the leaves. Most leaf traits and biomass characteristics had strong interactions in their responses to light and water treatments. Allometric analysis revealed that water and light had no effects on root to shoot ratios, main root to lateral root ratios, and root mass ratios. Shade alleviated the negative impact of drought. A. buergerianum successfully adapted to the various light and water conditions. We recommend a water supply above 15 % FC to keep the seedlings vigorous, under both sunlight conditions.
Acta Physiologiae Plantarum 35(4). · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A class of upwind finite volume element method based on tetrahedron partition is put forward for a nonlinear convection diffusion problem. Some techniques, such as calculus of variations, commutating operators and the a priori estimate, are adopted. The a priori error estimate in L 2 -norm and H 1 -norm is derived to determine the error between the approximate solution and the true solution.