刈割对生态浮床植物黑麦草光合作用及其对氮磷等净化效果的影响

Effects of Cutting on Photosynthesis and Purification Efficiencies on Nitrogen and Phosphorus of the Lolium multiflorum

以多花黑麦草为试材,通过水培实验方法,研究刈割强度对黑麦草生长、光合作用以及对污染水体氮、磷等去除效果的影响.结果表明,①刈割显著促进黑麦草新芽再生能力,刈割后5--13 d,C2（留茬2 cm）实验组新芽再生速率达2.78 cm.d^-1,远高于不刈割组（0.88 cm.d^-1）;刈割组株高、现存生物量以及生产量均大于不刈割组,且随刈割强度的增加,植物补偿指数显著变化,其中重度刈割（留茬高度≤5 cm）试验组新芽高度以及累积生物量分别为40.6--44.0 cm、31.6--37.2 g,均表现为超补偿作用,表明重度刈割有利于黑麦草生物量的累积;②刈割对黑麦草叶片叶绿素组成具有一定影响,其中C2组叶绿素a、叶绿素a/b最大,为1.85 mg.g^-1、3.18,C1（不刈割）组最小,为C2组的89.29%、90.13%;③刈割对黑麦草叶片叶绿素荧光参数有显著影响,随刈割强度的增加,PSⅡ的实际光能转化效率（ФPSⅡ）以及PSⅡ的非循环电子传递速率（ETR）均有所升高,其中C2组ФPSⅡ、ETR分别为C1组的1.13、1.09倍,表明刈割显著提高了叶片对光能的转化,使植物光合作用能力提高;④刈割显著提高了黑麦草系统对氮、磷等的去除效果,且刈割强度越大,浮床系统对TN、NH4^＋-N、TP、COD的去除率越好,其中C2组对TN、NH4^＋-N、TP、COD的去除率比C1组高1.07、1.20、1.05、1.44倍,远高于无植物系统的去除率;⑤留茬2--5 cm为黑麦草刈割最佳高度,此结论可为浮床植物科学管理提供重要依据.

Effects of different cutting intensities on the growth, photosynthesis and the purification efficieneies on nitrogen and phosphorus of the Lolium multiflorum by hydroponics experiment method were studied. The results were shown as followings： ① Cutting could promote regeneration capacity of the Lolium multiflorum, and sprout regeneration rate in C2 （stubble = 5 cm） achieved 2.78 cm.d^-1 after being cut 5 to 13 d, which was significantly more than zero-cutting（0.88 cm.d^-1）. The height, standing-biomass, productivity of cutting groups were significantly more than zero-cutting. Their compensation capacities were raised with the increase of cutting intensity, and the sprout height , total biomass of the serious cutting groups were 40.6-44.0 cm, 31.6-37.2 g, which indicates that the serious cutting is good for the biomass cumulation of the Lolium multiflorum. ②Different cutting intensities have obvious effects on the chlorophyll contents of Lolium multiflorum： the chla and chla/chlb in C2 were about 1.85 mg.g^-1,3.18, which was highest in treating groups, while they were lowest in zero-cutting.③The fluorescence chorophyll parameters had a significant changes in the different cutting intensities. With increasing cutting intensity, the values of ФPS Ⅱ and ETR were significant increased： the ФPS Ⅱ and ETR in C2 were about 1.13 and 1.09 times of those in zero-cutting, indicating cutting could improve the photosynthetic capacity of Lolium multiflorum. ④The purification efficiencies on TN, NH4^＋ -N, TP and COD had a significant increase with the cutting intensities increase, and the purification rate on TN, NH4^＋ -N, TP and COD of C2 was 1.07,1.20, 1.05,1.44 times more than zero-cutting respectively. ⑤About 2-5 cm of stubble was the best cutting height of Lolium multiflorum, which can applied a technical references for ecological bed management.