【作者】 段永宏；

【导师】 徐程扬；

【作者基本信息】 北京林业大学 ， 森林培育， 2008， 硕士

【摘要】 为探索根系功能、科学合理划分根系径级,本论文以长白山地区自然条件下水曲柳为研究对象,对水曲柳的根系呼吸特性、根系呼吸对温度和湿度以及养分的短期反映进行了研究。主要研究结果如下:1.水曲柳整体根系呼吸速率在林木根系生长和生理活动较为活跃的7月份达到最高水平,在测定时间内16、25、29和47年生水曲柳根系呼吸速率最小值均出现在11月份,其次是5月份。2.水曲柳不同径级单位根系表面积呼吸速率随着直径的增加而提高,不同根系径级间呼吸速率差异极显著(P<0.01),单位根系体积呼吸速率(P=0.048)和比呼吸速率(P=0.11)随根系直径的增加降低。3.基于根系表面积及干重测定的水曲柳的维持呼吸、生长呼吸和根系径级之间的关系与根系总呼吸速率和径级的关系一致,即:单位根系表面积呼吸速率随着根系径级的增加而提高,而单位根系干重呼吸速率则随着根系径级的增加降低。基于根系体积测定的水曲柳的生长呼吸和根系径级之间的关系与此一致,但维持呼吸变化规律相反。水曲柳的根系维持呼吸所占比例随着根系直径的加大而提高。4.水曲柳根系呼吸速率均随着测定温度的升高显著加强,同一温度下,单位根系表面积呼吸速率随着根系径级的增加而加强,单位根系体积和干重呼吸速率则随着根系径级的增加而降低。5.养分供给量对水曲柳根系呼吸有极显著的影响。氮供给量对单位体积呼吸速率和比呼吸速率的影响显著程度比对单位表面积根系呼吸速率的影响更加强烈,二者均达到了极显著水平(P<0.001)。6.根系径级<2mm、2-5mm和>5mm根系呼吸速率整体上与土壤温度、土壤湿度和土壤氮含量之间呈正相关趋势,即水曲柳不同径级根系呼吸随着土壤温度、土壤湿度和土壤氮含量在一定范围的提高而增加。不同土壤深度对水曲柳根系呼吸产生了极显著的作用。更多还原

【Abstract】 To explore root function, scientifically and reasonably classifying root diameter, root respiration of natural Fraxinus mandshurica trees grown in the Changbai Mountain and its short-term responses to temperature, humidity and nutrient availability were studied in the paper. And the main results were as follow:1. The highest total root respiration rate of Fraxinus mandshurica occurred in July when the forest root growth and physiological activity is more active. The minimum value of root respiration rate of the trees of 16、25、29 and 47year-old appeared on May, and followed by November. The most possible reasons may be related to the low soil temperature and the physiologically unactive root.2. The root respiration rate of different root diameter would increase with the root diameter, and was obviously diffrenet among the root in different diameter(sP<0.01). But, the root respiration rate per root volume was significantly decrease with the increase of root diameter (P=0.048) while the specific root respiration rate was not significantly increase with diameter (P = 0.11).3. Based on the root surface area and root mass, the relationship is consistent with total root respiration rate, which are between maintenance root respiration rate, growth respiration rate and different root diameter relations. That is basing on root surface area , root respiration rate of different root diameter was increase with diameter ; and basing on dry root biomass , it reduces with diameter. The relation between growth respiration rate and different root diameter which is determined in the base of root volume, is also consistent with total root respiration rate, but is opposite with maintenance respiration. And the proportion that maintenance respiration ccounting for is increased with the increasing of the diameter.4. Root respiration rate of Fraxinus mandshurica was obviously increase with temperature. At the same temperature, root respiration rate based on root surface increases with the increase of root diameter while root respiration rate based on volume and mass changed oppositely.5. Root respiration rate of Fraxinus mandshurica was obviously affected by the fertilization of nitrogen.The sensitivity of root respiration based on root volume and mass response to the fertilization of nitrogen was higher than root respiration based on root surface area, but the difference of N treatment between them were both significantly (P <0.001).6. Respiration rate of root in diameter of <2mm, 2~5mm and >5mm positively correlated to the soil temperature, soil moisture and soil nitrogen, namely, root respiration rate of different root diameter increased with soil temperature, soil moisture and soil nitrogen contents in a certain extent.更多还原