不同平茬年限人工柠条林光合特性及土壤水分的响应变化
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引用本文:于瑞鑫,王 磊,蒋 齐,杨新国,陈 林,刘 凯,陈 娟.不同平茬年限人工柠条林光合特性及土壤水分的响应变化[J].西北植物学报,2019,39(3):506~515
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于瑞鑫1,2,王 磊1,2,4*,蒋 齐3,杨新国1,2,陈 林1,2,刘 凯1,2,陈 娟1,2 (1 宁夏大学 西北土地退化与生态系统恢复省部共建国家重点实验室培育基地银川 7500212 宁夏大学 西北退化生态系统恢复与重建教育部重点实验室银川 7500213 宁夏农林科学院 荒漠化治理研究所银川 7500024 南京大学 国际地球系统科学研究所南京 210093) 
基金项目:国家自然科学基金(31760707,41461046,31460161);
中文摘要:平茬是荒漠草原老化人工柠条林营林抚育的重要措施,为系统认识柠条平茬后连续的生理与生态响应过程及其变化规律,该研究设置对比观测样地,以未平茬柠条(WPC)为对照,以平茬后连续生长1~5年(PC1~PC5)的柠条为处理,对各样地柠条净光合速率、蒸腾速率、气孔导度、胞间CO2浓度、水分利用效率等光合生理特征及其土壤含水量分布的影响进行测定分析。结果表明:(1)平茬处理对柠条生理特性的影响因平茬年限的增加而异,其中PC1和PC2柠条的净光合速率和蒸腾速率较WPC略有提高,PC1柠条处于补偿生长的活跃期,水分利用效率明显高于其他平茬处理,PC2柠条的水分利用效率开始下降;PC3和PC4的柠条蒸腾速率、净光合速率和气孔导度显著上升,且PC4处理下达到最大值,相应水分利用效率也逐步回升;PC5的柠条几乎不存在补偿性生长,净光合速率、蒸腾速率和水分利用效率开始回落,逐渐接近WPC;平茬措施对PC1与PC5柠条胞间CO2浓度大小的影响较大。(2)PC1的土壤水分含量在0~100 cm土层因受冠层截留大幅减小的影响而低于其他年限平茬处理;PC2的土壤水分略有改善,PC3、PC4的土壤含水量显著提高,PC5的土壤水分状况则逐渐接近于WPC。(3)随平茬年限的增加,柠条光合特性与土壤含水量间存在一定的动态互馈关系,其中PC1的土壤水分略有下降,柠条生长减缓;PC2土壤含水量逐步恢复;PC3土壤含水量增长幅度开始下降,柠条的各项生理指标上升;PC4柠条的光合生理指标、土壤含水量都达到了最高值;PC5柠条的各项指标开始下降。研究发现,PC4处理是柠条光合生理和土壤水分响应变化的拐点,可参考作为平茬柠条优化管理的一个时间节点。
中文关键词:荒漠草原  柠条  平茬年限  光合作用  土壤含水量
 
Changes in Response to Photosynthetic Characteristics and Soil Water of Artificial Caragana intermedia with Different Pruning Years
Abstract:Pruning is an important measure for the aging of artificial Caragana intermedia in the desert steppe. It is a systematic understanding of the physiological and ecological response processes and their changes after the pruning of C. intermedia. The study sets a comparative observation plot to and using unpruned C. intermedia (WPC) as a control, and photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2 concentration, water use efficiency of C. intermedia were treated that continuously grown for 1 to 5 years (PC1-PC5). The photosynthetic physiological characteristics and the effects of soil water content and distribution were analyzed. The results showed that: (1) the effect of pruning treatment on the physiological characteristics of C. intermedia was different due to the increase in the number of pruning years. The photosynthetic rate and transpiration rate of PC1 and PC2 were slightly higher than that of WPC, and PC1 was in the active period of compensatory growth, and its water use efficiency was significantly higher than that in other pruning years of C. intermedia. The water use efficiency of C. intermedia in PC2 began to decrease. The transpiration rate, photosynthetic rate and stomatal conductance of PC3 and PC4 increased significantly, reached the maximum value in PC4 as well as the corresponding water use efficiency gradually recovered. Pruning measures had a greater impact on the intercellular CO2 concentration of C. intermedia in PC1 and PC5. (2) The water status of C. intermedia in PC1 was lower than that of other pruning years because the soil water content was significantly reduced by canopy closure at 0-100 cm; the soil water of C. intermedia in PC2 was slightly improved and it of C. intermedia in PC3 and PC4 was significantly increased, and the soil water status of C. intermedia in PC5 was gradually closer to that of WPC C. intermedia. (3) With the increase in the number of pruning years, there is a dynamic relationship between photosynthetic characteristics and soil water content of C. intermedia. The soil moisture of PC1 is slightly decreased, and the growth slowed down. The soil profile water content of C. intermedia in PC2 gradually recovered, and the growth rate of soil water content of C. intermedia in PC3 began to decline and the physiological indexes increased. The physiological indicators and soil water content of C. intermedia in PC4 reached its highest value. The indicators of PC5 began to decline. In summary, PC4 treatment is the inflection point of photosynthetic physiology and soil water response of C. intermedia, which can be used as a time node for optimal management of pruning C. intermedia.
keywords:desert steppe  Caragana intermedia  pruning years  photosynthesis  soil moisture
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