对割频率对皇竹草产量及光合生理生态的影响

【作者】 李德明；

【导师】 刘金祥； 张德；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2010， 硕士

【摘要】 本实验对研究对象皇竹草采用四个处理:每30天刈割一次(T1)、每60天刈割一次(T2)、每90天刈割一次(T3)、每120天刈割一次(T4)和对照(CK),刈割时留茬高度为15 cm。研究刈割频率与产量的关系,以及刈割频率对光合生理生态的影响,并系统的分析了皇竹草的光合特性。研究结果如下:(1)不同刈割频率对皇竹草的分蘖数和生长速度都有着很明显的影响。频繁刈割能增加皇竹草的分蘖数,但过度刈割其分蘖数则有减少的趋势。适度刈割不但可以促进生长还可以增加皇竹草的分蘖数。(2)皇竹草的刈割频率对产量有着至关重要的影响。在湛江地区,一般选择刈割频率为60天的刈割最适宜作为青饲料(产量高、适口性好、再生速度快);而作为青贮饲料或者作为种苗,刈割周期应该在90天左右。(3)不同刈割频率对皇竹草光合生理特性有一定的影响。本研究结果表明不同处理的皇竹草的同化能力强弱为T3>T2>T1>T4,T3处理的皇竹草产量最高,达到17.94 kg/株,为最佳刈割频率。(4)刈割能改变皇竹草净光合速率的日变化,能在一定程度上削弱皇竹草的“光合午休”现象。(5)T1和CK的暗呼吸速率比较高,分别为2.66μmol·m-2·s-1和2.19μmol·m-2·s-1。T2、T3、T4的暗呼吸速率在1.61～1.84μmol·m-2·s-1的范围内,低于T1和CK,说明适度的刈割能降低暗呼吸速率,频繁刈割反而使暗呼吸速率变大。(6)所有处理的CO2响应曲线都经历了在一开始线形增加后,紧跟着会拐向一个较缓慢增长的响应阶段。由此可知,皇竹草光合作用过程中主要为Pi再生的限制。随着刈割频率的增加,皇竹草的CO2补偿点降低,即随着刈割频率的增加,皇竹草的光合产物积累量增加。(7)T1羧化效率最高,0.256 mol·m-2·s-1,高于T2、T3、T4;T2、T3羧化效率相当;CK的羧化效率最低0.070 mol·m-2·s-1,故不同刈割频率下皇竹草对CO2的同化能力为T1>T2>T3,T4>CK。(8)皇竹草的光呼吸速率与其最大净光合速率的比值很小(0.06～0.13),因此皇竹草在合成的有机物时,光呼吸耗损较小,这有利于该类植物光合产物的积累。更多还原

【Abstract】 There are 4 treatments of Pennisetum hydridum: every 30 days(T1), every 60 days(T2), every 90 days(T3) and every 120 days(T4) in this study, to analyze the relationship between different cutting frequency and yield, and the effect of different cutting frequency on Photosynthetic physioecologica and Analysis of photosynthetic characteristics of Pennisetum hydridum. The rusults can be summarized as follow:(1)The cutting frequency significantly influence the tillers and growth speed of Pennisetum Hydridun. Frequent cutting can increase the number of tillers,but the number of tillers under over-cutting display decreasing trend. Moderate cutting not only promote growth,but also increase the number of tillers.(2)The cutting frequency of Pennisetum Hydridun has a critical influence on the yield. In the region of Zhanjiang, T2 was the best treatment for storage(high yield,good palatability,rapid regrow speed); T3 was the best treatment for storage or seedlings.(3)Different cutting frequency of Pennisetum Hydridun have some certain impact on the physiological characteristics.The results show that: Different treatment of Pennisetum Hydridun in the strength of the assimilation capacity is T3>T2>T1>T4, T3 is best treatment for yield of Pennisetum Hydridun.Up to 17.94 kg/plant.(4)Cutting can change diurnal variation of photosynthetic rate of Pennisetum. It can also weaken the Napier in the "midday depression" phenomenon to some extent.(5)The dark respiration speed were higher in T1 and CK,they were 2.66μmol·m-2·s-1and 2.19μmol·m-2·s-1, The dark respiration of T2,T3,T4 in the scale 1.61～1.84μmol·m-2·s-1。Below T1 and CK,indicated that medium cutting can slow the dark respiration speed,frequent cutting accelerate the dark respiration speed.(6)CO2 respond curve of all treatment liner increase at beginning,following with slowly increase stage.We known that photosynthesis process will restrict the regrow of Pi.As the increase of cutting frequency,the light compensation point of Pennisetum lower.As the increasing of cutting frequence, the accumulation of photosynthetic products increasing.(7)The carboxylation efficiency under T1 is the highest than T2,T3,T4; The T2 carboxylation efficiency equivalent with T3; CK is lowest,is 0.070 mol·m-2·s-1,so assimilation order of different treatment is T1>T2>T3, T4>CK.(8)The ratio photorespiration rate of Pennisetum compare to net photosynthetic rate si small(0.06~0.13).So in the synthesis process of organic, The loss of photorespiration is smaller,it is helpful to the accumulation of photosynthetic products.更多还原