CO2浓度与土壤水分胁迫对红松和云杉苗木影响的试验研究

全球气候变化对植物影响研究的主要内容是由于大气中CO2 浓度升高导致的气温升高和土壤干旱化对植物的影响。文中利用人工气候室试验研究了高CO2 浓度和土壤水分胁迫对红松和云杉的影响 ,结果表明 :CO2 浓度升高使红松和云杉生长量的增长率提高 ,土壤水分胁迫使树木生长量的增长率下降 ,且CO2 浓度升高的正效应要小于土壤水分胁迫的负效应。CO2 浓度升高使树木叶水势增大 ,土壤水分胁迫使树木叶水势减小 ,这从植物生理的角度说明了CO2 浓度变化和土壤水分胁迫对树木的影响机理 ,且在轻度干旱的情况下 ,高CO2 浓度使树木叶水势增大 ,但随着土壤干旱程度的加重 ,树木的叶水势逐渐减小。同时 ,从实验结果还可以看出 ,虽然大气中CO2 浓度和土壤湿度变化对苗木的影响显著存在 ,但与农作物和牧草等植物相比 ,这种影响仍要小得多。

EXPERIMENTAL STUDY ON THE IMPACTS OF CO2 CONCENTRATION AND SOIL WATER STRESSON ON NURSERY STOCKS OF PINUS KORAIENSIS SIEB.ET.ZUCC AND PICEA ASPERATA MAST

The purpose of the study is to investiste the impact of air temperature raising and soil drought tendency caused by atmospheric CO 2 concentration enrichment on plant species. The impacts of higher CO 2 concen tration and soil water stress on Pinus Koraiensis Sieb. Et. Zucc and Picea Asperata Mast. were studied by using artificial climatic chambers. The results showed that CO 2 concentration enrichment increased the increasing rate of growth value of Pinus Koraiensis Sieb. Et. Zucc and Picea Asperata Mast., but the soil water stress decreased it. The positive effects of CO 2 concentration enrichment were smaller than that the negative effects of soil water stress. As compared with ambient CO 2 concentration and suitable soil water, the plant height, basal diameter and total branch length of Pinus Koraiensis Sieb. Et. Zucc in CO 2 enrichment and slight soil drought decreased by 0.79%, 2.32% and 3.53%, respectively, the Picea Asperata Mast decreased by 2.14%, 0.04% and 2.72%. The plant height, basal diameter and total branch length of Pinus Koraiensis Sieb. Et. Zucc in CO 2 enrichment and grave soil drought decreased by 2.81%, 2.80% and 4.97%, respectively, the Picea Asperata Mast. decreased by 3.49%, 0.99% and 4.15%. Therefore, atmospheric CO 2 enrichment is favor to nursery stock growth, but the net increment rate of nursery stock growth value in soil water stress is still decreasing. CO 2 concentration enrichment increased the leaf water potential, but the soil water stress decreased it. It is explained the impact machanism of CO 2 concentration changing and soil water stress on tree species from plant physiology. Under slight soil drought case, CO 2 concentration enrichment increased the leaf water potential, but together with soil drought aggravated, leaf water potential of tree species decreased gradually. In the status of CO 2 enrichment and slight soil water stress, the leaf water potential of Pinus Koraiensis Sieb. Et. Zucc and Picea Asperata Mast. increased by 0.41% and 0.44%, respectively. In the status of CO 2 enrichment and grave soil water stress, the leaf water potential of Pinus Koraiensis Sieb. Et. Zucc and Picea Asperata Mast. increased by 1.13% and 1.75%, respectively. Simultaneously, it can be seen from the experimental results, the significant impacts of atmospheric CO 2 concentration and soil moisture change on nursery stocks do exist, but the impacts are much smaller compare to the crops and pastures.