Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf traits.However,leaf structural and chemical traits variation among co-existing species,and plant functional types withi...Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf traits.However,leaf structural and chemical traits variation among co-existing species,and plant functional types within the canopy are poorly quantified.In this study,the seasonality of leaf chlorophyll,nitrogen(N),and phosphorus(P)were quantified vertically along the canopy of four major tree species and two types of herbs in a temperate deciduous forest.The role of shade tolerance in shaping the seasonal variation and vertical differentiation was examined.During the entire season,chlorophyll content showed a distinct asymmetric unimodal pattern for all species,with greater chlorophyll levels in autumn than in spring,and the timing of peak chlorophyll per leaf area gradually decreased as shade tolerance increased.Chlorophyll a:b ratios gradually decreased with increasing shade tolerance.Leaf N and P contents sharply declined during leaf expansion,remained steady in the mature stage and decreased again during leaf senescence.Over the seasons,the lower canopy layer had significantly higher chlorophyll per leaf mass but not chlorophyll per leaf area than the upper canopy layer regardless of degree of shade tolerance.However,N and P per leaf area of intermediate shade-tolerant and fully shade-tolerant tree species were significantly higher in the upper canopy than in the lower.Seasonal variations in N:P ratios suggest changes in N or P limitation.These findings indicate that shade tolerance is a key feature shaping inter-specific differences in leaf chlorophyll,N,and P contents as well as their seasonality in temperate deciduous forests,which have significant implications for modeling leaf photosynthesis and ecosystem production.展开更多
Muehlewbeckia complera was introduced to China in 2002 as indoor-hanging ornamental foliage plant. The experiment of the shade tolerance for this species was carried out in different light intensities (0.14–946.00 μ...Muehlewbeckia complera was introduced to China in 2002 as indoor-hanging ornamental foliage plant. The experiment of the shade tolerance for this species was carried out in different light intensities (0.14–946.00 μmol·m?2·s?1). After 40 days in experimental areas, leaf photosynthentic characteristics indexes ofM. complera in different photosynthesis active radiation (PAR) were measured with LI-COR6400 apparatus, such as the light compensation point, light saturation point, and maximum net photosynthesis rate, at the same time, the increments of total leaf area and leaf amount were measured. The results showed that the optimum light intensity range forM. complera was from 9.26 μmol·m?2·s?1 to 569.00 μmol·m?2·s?1 (463–28150 lx, relative humidity (RH) for 46–60%, temperature at 16–22°C). Under this condition, leaf photosynthetic efficiency was tiptop. AlthoughM. complera belonged to the moderate sun-adaptation plant species, the plant growth was inhibited when PAR increased to the level of 569.000 μmol·m?2·s?1 or above.M. complera could sprout new leaves in photosynthesis active radiation of 0.16–19.22 μmol·m?2·s?1 (8–961 lx), or 10 μmol·m?2·s?1 for above 6 h. Keywords Muehlewbeckia complera - Shade tolerance - Cultivation - Photosynthesis CLC number S602.1 Document code A Foundation item: This study was supported by the Research Foundation of Northeast Forestry University.Biography: YUE Hua (1962-), female, Associate professor in Northeast Forestry University, Harbin 150040, P. R. China.Responsible editor: Zhu Hong展开更多
Maize is an important food crop, as well as the irreplaceable feed and industrial materials, having huge market demand in China. Southwestern region of China is the third largest main maize producing zone, and the fre...Maize is an important food crop, as well as the irreplaceable feed and industrial materials, having huge market demand in China. Southwestern region of China is the third largest main maize producing zone, and the frequent occurrence of abiotic stress conditions such as drought, heat, cold, wet shaded stress have severely affected the development of maize production, causing low and unstable corn yields, severely restricting the maize industry development in the southwest of China. This paper preliminarily describes the maize resistance to abiotic stresses in southwestem region of China, putting forward the countermeasures and the key research direction in the practice of breeding in order to provide reference for the cultivation of new varieties with high yield and stress resistance, and improving the levels of maize stress resistance breeding in southwestern region of China.展开更多
The presence of species diversity in the ecosystem is an important aspect. Simply put, the loss of biodiversity and the formation of ecosystems into monocultures would reduce the productivity of the forest ecosystem t...The presence of species diversity in the ecosystem is an important aspect. Simply put, the loss of biodiversity and the formation of ecosystems into monocultures would reduce the productivity of the forest ecosystem than it has abundant diversity. This study conducted with a purpose to get the basic information regarding the effect of shade on the seedling growth. Understanding these relationships in the early years may reveal the important information, which will be helpful for managing and evaluating the silviculture practices. The study was conducted at Dirab Experiments and Agricultural Research Station, South of Riyadh. The experimental plot was managed under the corridor of Eucalyptus camaldulensis stands. Twenty seedlings of Vachellia farnesiana with relative similar height and diameter were planted in each block at a 5 × 5 m2 spacing in March 2017. Three different treatments were established and relatively categorized into Line 1 (without shade), Line 2 (shade until 09:00 a.m.), and Line 3 (shade until 11:00 a.m.). Eight months after planting, several morphological parameters were monthly assessed from November 2017 until April 2018. Also, the number of fruits was observed following the fruit’s season. Seedling growth variation as an effect of shading occurred between the lines of planting in this experiment. The seedling growth was significantly increased by shading treatment, even though target plant species (V. farnesiana) is categorized as intolerant species. Basically, shade helps to generate the favorable local environment for supporting plant growth. This treatment with an appropriate consideration might become an alternative practice for increasing plant productivity.展开更多
基金This work was supported by the National Natural Science Foundation of China(32171765).
文摘Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf traits.However,leaf structural and chemical traits variation among co-existing species,and plant functional types within the canopy are poorly quantified.In this study,the seasonality of leaf chlorophyll,nitrogen(N),and phosphorus(P)were quantified vertically along the canopy of four major tree species and two types of herbs in a temperate deciduous forest.The role of shade tolerance in shaping the seasonal variation and vertical differentiation was examined.During the entire season,chlorophyll content showed a distinct asymmetric unimodal pattern for all species,with greater chlorophyll levels in autumn than in spring,and the timing of peak chlorophyll per leaf area gradually decreased as shade tolerance increased.Chlorophyll a:b ratios gradually decreased with increasing shade tolerance.Leaf N and P contents sharply declined during leaf expansion,remained steady in the mature stage and decreased again during leaf senescence.Over the seasons,the lower canopy layer had significantly higher chlorophyll per leaf mass but not chlorophyll per leaf area than the upper canopy layer regardless of degree of shade tolerance.However,N and P per leaf area of intermediate shade-tolerant and fully shade-tolerant tree species were significantly higher in the upper canopy than in the lower.Seasonal variations in N:P ratios suggest changes in N or P limitation.These findings indicate that shade tolerance is a key feature shaping inter-specific differences in leaf chlorophyll,N,and P contents as well as their seasonality in temperate deciduous forests,which have significant implications for modeling leaf photosynthesis and ecosystem production.
基金Supported by the Research Foundation of Northeast Forestry University.
文摘Muehlewbeckia complera was introduced to China in 2002 as indoor-hanging ornamental foliage plant. The experiment of the shade tolerance for this species was carried out in different light intensities (0.14–946.00 μmol·m?2·s?1). After 40 days in experimental areas, leaf photosynthentic characteristics indexes ofM. complera in different photosynthesis active radiation (PAR) were measured with LI-COR6400 apparatus, such as the light compensation point, light saturation point, and maximum net photosynthesis rate, at the same time, the increments of total leaf area and leaf amount were measured. The results showed that the optimum light intensity range forM. complera was from 9.26 μmol·m?2·s?1 to 569.00 μmol·m?2·s?1 (463–28150 lx, relative humidity (RH) for 46–60%, temperature at 16–22°C). Under this condition, leaf photosynthetic efficiency was tiptop. AlthoughM. complera belonged to the moderate sun-adaptation plant species, the plant growth was inhibited when PAR increased to the level of 569.000 μmol·m?2·s?1 or above.M. complera could sprout new leaves in photosynthesis active radiation of 0.16–19.22 μmol·m?2·s?1 (8–961 lx), or 10 μmol·m?2·s?1 for above 6 h. Keywords Muehlewbeckia complera - Shade tolerance - Cultivation - Photosynthesis CLC number S602.1 Document code A Foundation item: This study was supported by the Research Foundation of Northeast Forestry University.Biography: YUE Hua (1962-), female, Associate professor in Northeast Forestry University, Harbin 150040, P. R. China.Responsible editor: Zhu Hong
基金Supported by the Corn Heat-resisting Resources Exploitation and Chain Molecular Marker Development(cstc2015jcyj BX0112)the Screening and Breeding of Feeding Maize Varieties in the Hilly and Mountain Areas(cstc2016shms-ztzx80017)+5 种基金the Functional Corn Germplasm Renounces Precise Identification and Material Innovation(cstc-2016shms-ztzx80013)the Breeding of Maize CMS Materials(2013cstc-jbky-00565)the Screening and Creation of High-temperature and Drought Resisting Corn Materials(2013cstc-jbky-00564)the Creation and Application of Shade-tolerant Corn Germplasm(cstc2016shmszx0218)the Special Fund for Scientific and Technological Innovation of Social People’s Livelihood of Chongqing Municipality-Molecular Analysis of Corn Kernel Accumulated Amylose and Development and Application of Genetic Specific Markers(cstc2015shmszx80029)the Innovation of Fine Varieties of Chongqing Academy of Agricultural Sciences-Research and Application of the Combining Ability of High-efficient Retrospective Improved Corn(NKY-2016AB004)~~
文摘Maize is an important food crop, as well as the irreplaceable feed and industrial materials, having huge market demand in China. Southwestern region of China is the third largest main maize producing zone, and the frequent occurrence of abiotic stress conditions such as drought, heat, cold, wet shaded stress have severely affected the development of maize production, causing low and unstable corn yields, severely restricting the maize industry development in the southwest of China. This paper preliminarily describes the maize resistance to abiotic stresses in southwestem region of China, putting forward the countermeasures and the key research direction in the practice of breeding in order to provide reference for the cultivation of new varieties with high yield and stress resistance, and improving the levels of maize stress resistance breeding in southwestern region of China.
文摘The presence of species diversity in the ecosystem is an important aspect. Simply put, the loss of biodiversity and the formation of ecosystems into monocultures would reduce the productivity of the forest ecosystem than it has abundant diversity. This study conducted with a purpose to get the basic information regarding the effect of shade on the seedling growth. Understanding these relationships in the early years may reveal the important information, which will be helpful for managing and evaluating the silviculture practices. The study was conducted at Dirab Experiments and Agricultural Research Station, South of Riyadh. The experimental plot was managed under the corridor of Eucalyptus camaldulensis stands. Twenty seedlings of Vachellia farnesiana with relative similar height and diameter were planted in each block at a 5 × 5 m2 spacing in March 2017. Three different treatments were established and relatively categorized into Line 1 (without shade), Line 2 (shade until 09:00 a.m.), and Line 3 (shade until 11:00 a.m.). Eight months after planting, several morphological parameters were monthly assessed from November 2017 until April 2018. Also, the number of fruits was observed following the fruit’s season. Seedling growth variation as an effect of shading occurred between the lines of planting in this experiment. The seedling growth was significantly increased by shading treatment, even though target plant species (V. farnesiana) is categorized as intolerant species. Basically, shade helps to generate the favorable local environment for supporting plant growth. This treatment with an appropriate consideration might become an alternative practice for increasing plant productivity.
