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Chinese Academy of Forestry (2009)

Studies on Evaluation of Drought Resistance of Main Afforestation Tree in the South Edge of Taklimakan Desert

李磊; Li Lei

Titre : Studies on Evaluation of Drought Resistance of Main Afforestation Tree in the South Edge of Taklimakan Desert

Auteur : 李磊; Li Lei

Grade : Master’s Theses 2009

Université : Chinese Academy of Forestry

Résumé
The key environmental stress is the drought and short of water resource, which restrict the economy, society development and environment protection of arid zones in our country. In the arid zones in west China, researching the mechanisms of drought resistance, selecting the plant species with higher drought resistance, and increasing the technique of saving water, which are important especially to the environment improvement of our country and to the development of the West Regions. Imitating the condition of drought how to release the water of soil in Moyu County, Xinjiang province.The relative mean soil water contents of different irrigating treatment were 85%, 70%, 47% and 24%. By measuring the Physiological Characteristics of 6 plant species in order to compare the drought resistance.Two years old seedlings of Populus euphratica and Populus bolleana were chosen and planted in field, then were treated by different amount of irrigation in Moyu County, Xinjiang province. According to measuring the water potential of P. euphratica and P. bolleana under different conditions and at different time, it was shown that their variation trends are“V”figures in a day. The mean daily leaf water potential of P. euphratica was higher than P. bolleana. Comparing the net photosynthetic rate, transpiration rate and water use efficiency of two species, it is turned out the net photosynthetic rate, the transpiration rate and water use efficiency of P. euphratica was higher than P. bolleana. The leafδ13C value of P. euphratica was significantly higher than P. bolleana.Two years old seedlings of Elaeagnus mooceroftii and Elaeagnus oxycarpa were chosen and planted in field, then treated by different mount of irrigation in Moyu County of Xinjiang province. By measuring the leaf water potential of E. mooceroftii and E. oxycarpa under different conditions and at different time, it was shown that their variation trends followed a“V”shape in whole day. The mean daily leaf water potential of E. mooceroftii (-0.87±0.18 Mpa) was higher than that of E. oxycarpa. Comparing the net photosynthetic rate, transpiration rate and water use efficiency of two species, it is turned out the net photosynthetic rate (10.03±1.19μmol·m-2·s-1), the transpiration rate (11.06±0.88 mmol·m-2·s-1) and water use efficiency (0.80±0.09μmol·mmol-1) of E. mooceroftii were higher than that of E. oxycarpa. The leaf δ13C value of E. mooceroftii (-26.06±0.08‰) was significantly higher than that of E. oxycarpa. Elaeagnus mooceroftii and E. oxycarpa grew well under higher soil water contents (85%, 70% and 47%), whereas they showed significantly drought stress under irrigation of 24% soil water content. And then the net photosynthetic rate and water use efficiency of E. mooceroftii were higher (3.26μmol·m-2·s-1, 0.06μmol·mmol-1) than that of E. oxycarpa. The leaf water potential of E. mooceroftii was lower 0.06 Mpa than that of E. oxycarpa.Two years old seedlings of Haloxylon ammodendron and Tamarix hohenackeri were chosen and planted in field, then were treated by different mount of irrigation in Moyu County, Xinjiang province. According to measuring the leaf water potential of H. ammodendron and T. hohenackeri under different conditions and at different time, it was shown that their variation trends are“V”figures in a day. The mean daily water potential of .T. hohenackeri was higher than H. ammodendron. Comparing the net photosynthetic rate, transpiration rate and water use efficiency of two species, it is turned out the net photosynthetic rate and water use efficiency of H. ammodendron was higher than T. hohenackeri. Its transpiration rate was lower than T. hohenackeri. Theδ13C value of H. ammodendron was significantly higher than T. hohenackeri.The law of variation of the Stomata conductance of six plants which reach the maximum and then slow down in the morning . the Stomata conductance rise after reach the minimum .Following the drought aggravation, the donwtrend of the Stomata conductance of six plants is similar to Pn and Tr .

Mots clés : Drought resistance Drought resistance mechanism Evaluation Photosynthesis Water use efficiency Water potential

Présentation (CNKI)

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