炭疽病对山西晋北饲用燕麦地上部碳氮磷化学计量学特征的影响

C、N、P化学计量学特征有助于了解植物生长过程中的碳同化能力和养分元素的利用效率,并诊断限制性元素,但病害对植物化学计量特征影响的研究尚缺乏报道。本研究以山西晋北罹患炭疽病的饲用燕麦为对象,测定了不同发病程度植株地上部C、N、P含量及化学计量值,并初步探讨了其与病害发生持续时间、品种和种植模式之间的关系。结果表明: 随着发病程度增加,C、N、P含量呈下降趋势,其中重度发病植株的C、N、P含量分别较健康植株显著降低了5.4%、20.0%、24.2%;C∶N和C∶P呈升高趋势,其中重度发病植株的C∶N、C∶P较健康植株显著增加了18.5%和22.2%。不同采样点的发病程度对C含量均未造成影响,表明3种饲用燕麦品种具有一定的耐病保产能力;但N、P的化学计量值存在地点间变异,采样点病害持续时间越长,N、P的损失越严重。与单播燕麦相比,炭疽病降低了混播燕麦对P的利用优势。总之,炭疽病对晋北饲用燕麦碳同化能力造成一定程度的负面影响,加重了植株地上部受N、P养分限制的程度,但显著提高了N、P的利用效率。生产实践中需采取必要的防治措施,减轻病害对饲用燕麦经济收益和生态功能的不利影响。

Effects of anthracnose on C,N and P stoichiometry in the shoot of forage oat in north Shanxi Province,China

The C, N and P stoichiometry are helpful to understand the capacity of carbon assimilation and nutrient utilization efficiency during plant growth, as well as to diagnose nutrient limitation status. There is still a knowledge gap about the effects of disease on plant stoichiometry. In this study, forage oats (Avena sativa) suffering from anthracnose were the object of research conducted in north Shanxi Province. The C, N and P stoichiometry in the shoot of oat were examined at different degrees of disease occurrence. We analyzed the relationship of plant stoichiometry with disease duration, cultivar, and cultivation methods. The results showed that C, N and P contents decreased with the increasing degree of disease occurrence. The C, N and P contents in the plants with serious disease were significantly lower than that of healthy plants with a decreasing rate of 5.4%, 20.0% and 24.2%, respectively. C:N and C:P showed an increasing trend with the increases of the degree of disease occurrence. C:N and C:P of the plants with serious disease were significantly increased by 18.5% and 22.2%, respectively, than that of healthy plants. There was no significant difference for C content among different sampling sites, which indicated that the three varieties of forage oats might have disease tolerance capacity to ensure crop production. However, the stoichiometric values of N and P varied from place to place. The longer the disease duration was, the more reduction of N and P contents. Compared with monoculture oats, the P utilization efficiency of mixture oats was decreased by anthracnose. In summary, anthracnose had negative impacts on carbon assimilation capacity of forage oats in northern Shanxi. Anthracnose increased the restriction of N and P nutrition on the aboveground parts. However, anthracnose significantly improved N and P utilization efficiency. For the production practice, it was recommended to take necessary control measures to reduce the adverse effects of diseases on the economic benefits and ecological functions of forage oats.