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| Effects of drought and waterlogging on growth and photosynthesisof potted young Pinus tabulaeformis Carr. |
| Wang Qiao1,2, Liu Xiumei1,2, Wang Huatian1,2, Meng Xianpeng3, Cao Guiping3, Li Jian3, Huang Changbao3 |
| 1. College of Forest,Shandong Agricultural University, Key Laboratory of Silviculture of Shandong Province, 271018, Tai’an,Shandong,China;2. Taishan Forest Ecosystem Research Station, State Forestry Administration, 271018, Tai忆an,Shandong,China;3. Taishan Scenic Area Management Committee, 271000, Tai’an,Shandong,China |
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Abstract Drought and waterlogging are the main ecological adversities which affect the survival, growth and vigor of Pinus tabulaeformis Carr. In order to determine the influence of water condition on the growth and physiological adaptation to water stress of P. tabulaeformis trees, the growth of roots and needles,biomass distribution and photosynthesis of 4-year-old potted young trees under continuous drought,waterlogging and normal conditions were studied. We also measured indexes including soil water potential, branch water potential, net photosynthetic rate, transpiration rate, stomatal conductance,intercellular CO2 concentration, root mass, stem mass, leaf mass, total biomass, caliper and the length,surface area, and diameter of needles and roots. The results showed that: 1) The roughness and number of fine roots increased at the early stage of drought stress, but when the drought stress was prolongated,the growth vigor gradually declined with reduced number of fine roots. The soil water potential and branch water potential were also significantly reduced. The plants were easier to die when the stress time was more than 50 days. During water stress, net photosynthetic rate, transpiration rate, stomatal conductanceand intercellular CO2 concentration showed a continuous decline. 2) A short period of waterlogging stresshad no significant effect on growth, but chlorosis content descended and needle color turned yellow withsoil water potential and branch water potential increasing under long term of drought stress. Moreover,when the waterlogging lasted for more than 20 days, the fine roots began to decompose and the plantswent to die. During the waterlogging stress, stomatal conductance decreased with net photosynthetic rateapproaching to zero, but intercellular CO2 concentration increased. 3) Drought and waterlogging stressinhibited the growth significantly, and the biomass of roots, stems and needles decreased with stress time increasing. The descending range of drought stress treatment was larger than waterlogging treatment. In consequence,during dry seasons, soil moisture condition should be controlled in order to promote the growth of fine roots and enhance water use efficiency of P. tabulaeformis trees. When the rainy seasons come, high temperature and soil moisture content lead to more anaerobic respiration and rotted roots with tree vigor declining. More seriously, the P. tabulaeformistrees could die. Therefore we should control the amount of soil moisture content, pay attention to checking whether the rhizosphere soil is subjected to waterlogging. If necessary, drainage measures should be taken in time to ensure that the drainage depth is below concentrated distribution layer of roots, so as to ultimately optimize the cultivating method and raise survival rate of P. tabulaeformisseedlings.
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Received: 17 November 2014
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ZHU Hong, WANG Lu, KONG Linggang, BI Sisheng, MENG Shiyuan, ZHANG Zhihao, WANG Huatian, ZHAN Zhongcai, LIU Xiumei, TANG Jin, CHEN Shuying, CONG Guizhi. Effect of irrigation with magnetized saline water on grape seedlings and ionic homeostasis[J]. SSWC, 2020, 18(1): 131-139. |
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