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羊草(Leymus chinensis)是北方草原的重要牧草。准确评估其营养状况,对维护羊草草原的生产力具有重要意义。以羊草幼苗为材料,利用能同时表征2个光系统光化学活性的叶绿素荧光检测技术,对缺氮和缺磷处理下的叶片光化学活性进行分析。结果表明,缺氮处理20天后羊草叶片叶绿素含量降低近50%。同期缺磷及缺氮处理对PSⅡ功能的影响总体大于PSⅠ。与对照相比,缺氮叶片的Φ(Ⅱ)和Φ(Ⅰ)分别比对照降低了30.3%与38.5%;ETR(Ⅱ)与ETR(Ⅰ)分别降低30.8%和28.9%。缺磷处理组Φ(Ⅱ)和ETR(Ⅱ)的降低幅度约为缺氮的1/2。这些定量研究结果对及时有效地诊断和区分羊草植物氮磷缺乏状况具有重要的参考价值。
Leymus chinensis is an important pasture in the northern steppe. Accurate assessment of their nutritional status is of great significance for maintaining the productivity of the Leymus chinensis grassland. The leaves of Leymus chinensis were used as materials to analyze the photochemical activity of leaves under nitrogen and phosphorus deficiency using the chlorophyll fluorescence detection technique which can simultaneously characterize the photochemical activities of the two photosystem. The results showed that the chlorophyll content of Leymus chinensis decreased by nearly 50% after 20 days of nitrogen deficiency treatment. In the same period, the effects of phosphorus deficiency and nitrogen deficiency on PSⅡ function were generally greater than those of PSⅠ. Compared with the control, the Φ (Ⅱ) and Φ (Ⅰ) of nitrogen-deficient leaves decreased by 30.3% and 38.5%, respectively. The ETR (Ⅱ) and ETR (Ⅰ) decreased by 30.8% and 28.9%, respectively. Phosphorus deficiency treatment Φ (Ⅱ) and ETR (Ⅱ) to reduce the rate of about 1/2 of nitrogen deficiency. These quantitative results of the timely and effective diagnosis and differentiation of nitrogen and phosphorus deficiency in Leymus has important reference value.