CO_2浓度升高和模拟氮沉降对青川箭竹叶营养质量的影响  

Effects of elevated CO_2 and nitrogen deposition on leaf nutrient quality of Fargesia rufa Yi

作　　者：周先容[1] 汪建华[1] 张红[2] 王进闯[3] 张远彬[3] 

机构地区：[1]长江师范学院生命科学与技术学院,涪陵408100 [2]乐山职业技术学院,乐山614000 [3]中国科学院成都生物研究所,成都610041

出　　处：《生态学报》2012年第24期7644-7653,共10页Acta Ecologica Sinica

基　　金：中国科学院"西部之光"人才培养计划之西部博士项目(09C2031100);国家自然科学基金项目(30871999);重庆市自然科学基金项目(cstc2012jjA00006)

摘　　要：通过研究大熊猫主食竹之一的青川箭竹(Fargesia rufa Yi)叶营养质量对CO2浓度升高和模拟氮沉降的响应,预测在气候变化下箭竹和大熊猫之间的取食关系,以期为大熊猫的长久保护提供科学参考。利用人工环境控制生长室对青川箭竹幼苗进行了1个生长季节的大气CO2浓度和施氮处理:(1)CON(对照,不添加N和环境CO2浓度),(2)EC(环境CO2浓度+350μmol/mol、不添加N),(3)EN(添加5 g N m-2a-1、环境CO2浓度),(4)ECN(环境CO2浓度+350μmol/mol、添加5 g N m-2a-1)。结果表明:EC处理对青川箭竹叶片的C含量无显著影响,但降低了叶片中N和P含量,从而导致C∶N增加,而N∶P没显著变化。另外,EC处理增加了叶片中可溶性蛋白、可溶性糖、淀粉、蔗糖和果糖的含量,但降低了木质素和纤维素含量。同时,EC也明显增加了叶片中防御物质单宁的含量。另一方面,EN处理显著降低了叶片中C的含量,并增加了N的含量,但没有改变P的含量,从而C∶N减小,而N∶P增加。EN显著提高了箭竹叶片可溶性蛋白、可溶性糖和木质素含量,减少了淀粉和纤维素,但对单宁无明显影响。ECN减少了箭竹叶的单宁和N、P的含量,但显著增加了叶的可溶性蛋白、可溶性糖、果糖、蔗糖和淀粉含量。大气CO2浓度升高和氮沉降对叶的N、单宁、可溶性糖和淀粉含量具有显著的交互作用。在未来气候变化情景下,箭竹叶营养质量提高将可能影响叶的生物化学过程以及箭竹-大熊猫之间的取食关系。Rising atmospheric carbon dioxide （CO2 ） levels and increasing nitrogen deposition resulting from human activities have the potential to alter leaf nutrient quality and consequently alter plant/herbivore interactions. Fargesia rufa （Poaceae： Bambusoideae） is an important dietary bamboo for endangered giant pandas and is very vulnerable to climate change because it is one of the most widely distributed understory plants in subalpine coniferous forests in the southeastern Qinghai-Tibetan Plateau of China. Elevated CO2 and nitrogen deposition will lead to change in the nutrient quality of F. rufa leaves, which could influence the growth and fecundity of giant pandas. Thus, understanding how elevated CO2 and nitrogen deposition might change the nutritional quality and chemical defenses of F. rufa is an essential first step in predicting how giant pandas will respond to this component of climate change. However, there have been no studies on this aspect of F. rufa biology. The objects of this study were to （ 1 ） determine the effects of elevated CO2 on the nutritive quality of F. rufa ; （2） examine the effects of nitrogen on the quality of F. rufa ; and （3） determine whether nitrogen alters the effects of elevated CO2 on the foliar quality of bamboo. For this purpose, 30 seedlings were grown in each of six environmentally-controlled chambers for one growing season under the following conditions： control （CON; ambient CO2 concentration and N level）, elevated CO2（EC; ambient CO2 concentration ＋ 350 μmol/mol, ambient N）, extra N （EN; 5 g N m-2 a-1, ambient CO2 concentration） , and a combined treatment with both elevated CO2 and extra N （ECN; ambient CO2 concentration ＋ 350 μmol/mol, 5 g N m-2 a-1 ）. Leaves were analyzed for concentrations of carbon （ C ）, nitrogen （N）, phosphorus （P）, soluble sugars, fructose, sucrose, lignin, cellulose, and C-based defensive compounds （tannins）. Compared with CON, the EC treatment did not affect C concentration in leaves but

关 键 词：碳水化合物 化学元素 气候变化 青川箭竹 单宁 

分 类 号：X173[环境科学与工程—环境科学]