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Beijing Forestry University (2013)

Drought and Salinity Resistant Physiology of Main Tree Species in Qaidam of China

董梅; Dong Mei

Titre : Drought and Salinity Resistant Physiology of Main Tree Species in Qaidam of China

Auteur : 董梅; Dong Mei

Grade : Doctoral Dissertation 2013

Université : Beijing Forestry University

Résumé
With main plantation tree species in Qaidam region:Tamarix hohenackeri Bge., H. ammodendron, Sympegma regelii Bge., Nitraria tangutorum Bobr., Potentilla fruticosa and Sabina chinensis (Linn.) Ant. as test materials, this paper comprehensively studied the physiological responses of plant growth, leaf water relations and photosynthetic characteristics to drought and salt stress, as well as the laws of water consumption of these tree species.The drought and salinity resistant physiology and water consumption characteristics of the six main plantation tree species were deeply analyzed in order to pave the way for screening and cultivation of adverse-resistant plants during vegetation recovery period in different site conditions and also to provide a scientific theoretical foundation for the ecological environment construction and returning farmland to forests or grassland project. By means of research, main conclusions are elicited as follows :(1) Drought resistant characters of the six main plantation tree species in Qaidam regionDrought stress significantly decreased stem height and specific leaf weight of Tamarix hohenackeri Bge., H. ammodendron, Sympegma regelii Bge., Nitraria tangutorum Bobr., Potentilla fruticosa and Sabina chinensis (Linn.) Ant. seedlings and the decrement were greater under higher drought stress.Drought tolerances of Nitraria tangutorum Bobr.and H. ammodendron were higher than those of Sympegma regelii Bge, and Tamarix hohenackeri Bge., Potentilla fruticosa and Sabina chinensis (Linn.)Ant. were the lowest.The impact of drought stresses on net photosynthetic rate of Sympegma regelii Bge.was the strongest, followed by the impact of Nitraria tangutorum Bobr.and Tamarix hohenackeri Bge., and the impact of H, ammodendron was the weakest.Through the net photosynthetic rate—light response model comparison analysis of Tamarix hohenackeri Bge., H. ammodendron, Sympegma regelii Bge., Nitraria tangutorum Bobr. and Potentilla fruticosa, simulation rectangular hyperbolic correction model worked best. When six plants species were in the same water conditions (full of water), the leaf water potential of H. ammodendron was the lowest, followed by that of Nitraria tangutorum Bobr. The leaf water potentials of Sympegma regelii Bge.and Tamarix hohenackeri Bge.were in the medium, and those of Sabina chinensis (Linn.)Ant. and Potentilla fruticosa were the highest.(2) Discrimination results of drought tolerant mechanism of the six tree speciesAccording to the wilting index the decreasing order of six plants species in decreasing order was Sabina chinensis (Linn.)Ant.>Potentilla fruticosa>Sympegma regelii Bge.>Tamarix hohenackeri Bge.> Nitraria tangutorum Bobr.>H. ammodendron, which indicated the stronger drought tolerance of Nitraria tangutorum Bobr.than other plants. According to the water use efficiency the decreasing order of six plants species was H. ammodendron>Nitraria tangutorum Bobr.>Tamarix hohenackeri Bge.> Sympegma regelii Bge.> Potentilla fruticosa> Sabina chinensis (Linn.)Ant. According to the drought resistant charaeters in decreasing order was H. ammodendron>Nitraria tangutorum Bobr.>Tamarix hohenackeri Bge.>Sympegma regelii Bge.>Potentilla fruticosa>Sabina chinensis (Linn.)Ant.According to the discrimination results of leaf water potential and soil relative water of the six tree species, H. Ammodendron, Nitraria tangutorum Bobr., Sympegma regelii Bge., Tamarix hohenackeri Bge.and Potentilla fruticosa were all patience dehydration drought-resistant plants under low water potential, and Sabina chinensis (Linn.)Ant.was patience dehydration drought-resistant plants under sub-low water potential. According to the discrimination results of leaf water potential and soil water potential, the six tree species were all patience dehydration drought-resistant plants under low water potential.(3) Salt resistant physiology of the six main plantation tree species in Qaidam regionThe status of plant growth and development were all affected seriously by the salt soil environment. H. Ammodendron and Potentilla fruticosa were both salt damaged under severe salt stress in15days. The impact of salt stress on Nitraria tangutorum Bobr.and Tamarix hohenackeri Bge.were small. The inhibition on diameter and height growth in the same plant is more significant due to the severer salt stress. The inhibition of growth in Potentilla fruticosa is the most significant under the same treatment. The impact of salt stress on specific leaf weight in Nitraria tangutorum Bobr., H. Ammodendron and Tamarix hohenackeri Bge.were not significant. However, the specific leaf weight of Potentilla fruticosa declined significantly, which suggested the low salt tolerance. The salt tolerance of Nitraria tangutorum Bobr.and Tamarix hohenackeri Bge.were greater than that of H. Ammodendron.The photosynthesis of plants was affected by the salt stress. The net photosynthetic rate of four plants was all declined significantly under salt stress. The net photosynthetic rate of Nitraria tangutorum Bobr.declined slowly, and then stay steadily, which indicated that Nitraria tangutorum Bobr.seedlings adapted the salty environment gradually. The curve of net photosynthetic rate in Tamarix hohenackeri Bge. seedlings changed gently under different salt stress, and the decreases were the smallest compared with other plant seedlings. The net photosynthetic rate of Potentilla fruticosa declined dramatically, and the decreases were the greatest. The net photosynthetic rate of H. ammodendron declined significantly at600mmol·L-1NaCl compare with the reduction at100mmol·L-1NaCl. To sum up the changes of all parameters in different plant species, the salt tolence capacity of Tamarix hohenackeri Bge.was the best, followed by Nitraria tangutorum Bobr.. The Potentilla fruticosa was of the worst salt tolence capacity.

Mots clés : drought stress; salt stress; growth; photosynthetic parameters; Qaidam region;

Présentation (CNKI)

Page publiée le 5 avril 2014, mise à jour le 30 septembre 2017