【作者】 冯长松；

【导师】 卢欣石；

【作者基本信息】 北京林业大学 ， 草业科学， 2010， 博士

【摘要】 紫花苜蓿是一种全球性栽培、适应性广、营养价值高、适口性优良的饲料作物,有“牧草之王”的美誉。近年来,我国随着农业产业结构调整、退耕还林还草工程、社会主义新农村建设,以及畜牧业的快速发展,使苜蓿产业化进程不断推进,其重要作用日益增加,在中国乃至世界的农牧业发展和生态环境建设中,有着越来越重要的作用。栽培苜蓿的目的在于获得高产,苜蓿生产本质上是光能驱动的一种生理活动。苜蓿秋眠性则是苜蓿秋季刈割后对短日照的反应,它与生产性能有着直接的关系,开展苜蓿光合生理研究有着重要的生产价值和理论意义。本试验对11个标准秋眠级苜蓿品种的光合特性进行了比较分析,探讨了其光合作用与环境因子的关系以及光合作用过程中资源利用状况,在此基础上研究不同秋眠等级苜蓿品种大田自然光周期过程中生长反应和控制条件下的光合响应,并对不同秋眠级苜蓿光合色素含量与吸收光谱进行了研究,结果表明:（1）极非秋眠型苜蓿净光合速率日变化曲线与其他秋眠型不同,春、夏、秋三个季节净光合速率日变化都呈“单峰”曲线,午后净光合速率下降的原因均为非气孔限制。其余秋眠型苜蓿净光合速率日变化表现出“单峰”,“双峰”等不同的变化趋势,日变化曲线类型因秋眠级、季节和生态因素而异。午间净光合速率下降的原因既有气孔限制的调节,也有非气孔限制的调节。（2）苜蓿净光合速率与气孔导度呈正相关,与胞间CO₂浓度负相关。影响苜蓿净光合速率日变化的主要生理因子是气孔导度和蒸腾速率。（3）不同秋眠级苜蓿光合作用对光、温、水存在季节差异。秋季对苜蓿净光合速率影响程度为光照强度＞温度＞空气湿度,春季对苜蓿净光合速率影响程度为光照强度＞空气湿度＞温度,夏季对苜蓿净光合速率影响程度为光照强度＞温度＞空气湿度。秋季光、温、水对不同秋眠型影响顺序是秋眠型:光照强度＞空气湿度＞温度;半秋眠型:光照强度＞温度＞空气湿度;非秋眠型:光照强度＞温度＞空气湿度;极非秋眠型:光照强度＞温度＞空气湿度。（4）秋季与春、夏季光能、水分利用效率日变化曲线一致,呈现先降低后升高的趋势。光能利用效率:春季＞秋季＞夏季。水分利用效率:春季＞夏季＞秋季。秋眠级间苜蓿生长季日同化量的差异显著,11个秋眠级苜蓿单位面积日同化量为春季＞夏季＞秋季。秋眠型间苜蓿日同化量顺序为极非秋眠型＞非秋眠型＞半秋眠型＞秋眠型。秋眠级间苜蓿生长季日蒸腾效率的差异显著,春季的蒸腾效率最高,秋季的蒸腾效率最低,且春季的蒸腾效率远高于夏季和秋季。整个生长季节中极非秋眠型的日同化量最大、蒸腾效率最高,非秋眠型次之,说明与秋眠、半秋眠型相比,极非秋眠、非秋眠型生长优势明显。（5）秋季11个秋眠级苜蓿光饱和点（LSP）变动范围为1178到1843μmol·m^-2·s^-1,光补偿点（LCP）的变动范围为25-69μmol·m^-2·s^-1。苜蓿光补偿点、光饱和点、表观量子产量较高,具有显著的阳生植物的光合作用特点。光饱和点大小顺序是,极非秋眠型＞非秋眠型＞半秋眠型＞秋眠型;秋眠型间光补偿点无一定明显规律。不同秋眠型苜蓿品种CO₂饱和点大小顺序为:UC-1465＞Pierce＞Archer＞Maverick。4个不同秋眠型苜蓿品种对CO₂的利用范围不同,UC-1465具有最宽的CO₂利用范围,其次是Pierce和Archer,Maverick对CO₂的利用范围最窄。（6）苜蓿存在明显的自然光周期规律。在春季光延长过程中,11个秋眠级苜蓿品种株高与春季日照长度呈极显著正相关,秋眠级间植株生长高度的差异不显著。秋季光长缩短过程中,11个秋眠级苜蓿品种再生株高与秋季日照长度呈显著或极显著负相关,秋眠级间植株再生高度的差异显著。不同秋眠型苜蓿的再生高度:极非秋眠型＞非秋眠型＞半秋眠型＞秋眠型。（7）国内首次系统研究了11个标准秋眠级苜蓿品种秋季光合色素含量的变化规律与光合色素吸收光谱。研究表明,秋季11个秋眠等级苜蓿具有相同的叶片光合色素吸收光谱,都在440 nm和663nm有一个吸收高峰,不同秋眠级苜蓿的光合色素光密度分析可采用相同的方法。秋季刈割后,11个秋眠级苜蓿具有相同的光合色素变化趋势,光合色素秋眠级间含量差异不显著,各秋眠级叶绿素含量与日照长度呈负相关,类胡萝卜素含量与日照长度呈正相关,相关性均不显著。更多还原

【Abstract】 Alfalfa is a global culture, wide adaptability, high nutritional value and excellent palatability of feed crops, the "king of grass" in the world. In recent years, along with the agricultural structure adjustment, returning farmland to pasture project, the building of new socialist countryside, as well as the rapid development of animal husbandry, so that alfalfa continuously push forward the industrialization process, its important role in increasing the agriculture and animal husbandry in China and the world industry development and ecological environment construction, has an increasingly important role. The purpose of cultivation is high-yielding .Alfalfa production is essentially a kind of light-driven physiological activity. The fall dormancy of alfalfa is a reflection for short daylength in autumn. It has a direct relationship in production performance. The reseach of photosynthetic physiology of alfalfa has an important significance in theory and production in autumn.This test compares with the photosynthetic characteristics of 11 standard fall dormancy rate varieties of alfalfa. It is discussed the relationship of photosynthesis coupled with environmental factors and the resource utilization situation of their photosynthesis .On this basis ,it is studied that the different fall dormancy rate of afalfa grows response in field during natural light cycle and artificial photosynthetic responses under controlled conditions. The photosynthetic pigment content and absorption spectra have been studied in different fall dormancy rate of alfalfa .It results showed that:（1） The net photosynthetic rate daily change of the extreme non- fall dormancy type of alfalfa is "single peak" curve in spring, summer and autumn. The decline causes of the net photosynthetic rate is non-stomatal limitation. The change shown by the "single peak", ’Twin Peaks"and the different trends in the net photosynthetic rate of the others fall dormancy type. Diurnal variation curves are different for different type fall dormancy, seasonal and ecological factors. The midday decline causes of the net photosynthetic rate are both the regulation of stomatal limitation and the regulation of non-stomatal limitation.（2） The net photosynthetic rate of alfalfa and stomatal conductance is positively correlated and is negative correlation for the intercellular CO₂ concentration. The main physiological factorsof the affecting the diurnal variation of net photosynthetic rate are stomatal conductance and transpiration rate.（3）The photosynthesis of different fall dormancy rate alfalfa exists seasonal differences on the light, temperature, water coupling effect. Autumn on the net photosynthetic rate of alfalfa impact: light intensity>temperature>air humidity ;spring: light intensity>humidity>temperature;summer: light intensiry>temperature>air humidity temperature. In autumn ,the order of light, temperature, water coupling of different typeseffection, fall dormancy type: light intensity>humidity> temperature; semi-dormancy type:light intensity>temperature>air humidity;non-fall dormancy type: light intensity>temperature>air humidity; extreme non-fall dormancy type: light intensity>temperature> air humidity.（4） LUE and WUE are the same curve in fall,spring and summer, showing the rising trend after the first reduction.LUE:spring （0.107）>autumn （0.035） > Summer （0.0335）. WUE: spring （10.05） >Summer （2.25） >autumn （1.67）. Different fall dormancy rate is a significant difference in the amount of assimilation. 11 fall dormancy rate of alfalfa on assimilation capacity per unit area : spring >summer> autumn.. Different fall dormancy type of assimilation : extreme non-fall dormancy type >non-autumn dormancy type>semi-dormancy type >fall dormancy type. Different fall dormancy rate is a significant difference for transpiration efficiency in the growing season . The highest transpiration efficiency is spring and autumn the least .Transpiration efficiency in spring is much higher than in summer and autumn. Throughout the growing season, extreme non-fall dormancy type is the largest amount of assimilation and the highest transpiration efficiency,followed by the non-autumn dormancy type. It descriptioned that the growth of the extreme non-fall dormancy type, the non-fall dormancy type have obvious advantages comparing dormancy, semi-dormancy type.（5）It changes that the LSP range of 1178 to 1843μmol.m^-2.s^-1 and the LCP range of 25-69μmol.m^-2.s^-1 in 11 fall dormancy rate of alfalfa. It is a significant photosynthetic characteristics of sun plants for higher LSP and LCP. the LSP law, extreme non-fall dormancy type > non-autumn dormancy type > Semi-fall dormancy type > fall dormancy type; The LCP of different fall dormancy-type is not the necessarily law. Extreme non-fall dormancy type ,non-fall dormancy type of performance have always been a high quantum efficiency. It indicated that their ability of high light intensity use is higher than fall dormancy type, semi-dormancy types.There are different CO₂ use scopes for 4 FD varieties.CSP:UC-1465> Pierce> Archer> Maverick. UC-1465 has the widest range of CO₂ use scopes, followed by Pierce and Archer. There is the narrowest scope of the use of CO₂ for Maverick.（6）There exists an obvious natural light cycle of alfalfa. The process of Light extend in spring, 11 fall dormancy varieties growth height are highly significant positive correlation to the length of the spring sunshine. Renewable height of differenent fall dormancy rate is significant differenent. 11 fall dormancy varieties growth height are highly significant negative correlation to the length of the fall sunshine.The renewable heightof different fall dormancy types of alfalfa: Extreme non-fall dormancy type> Non-autumn dormancy type > Semi-fall dormancy type > Fall dormancy type.（7） The first time, photosynthetic pigment content changes and absorption spectra is systematic studied in the 11 standard fall dormancy for fall dormancy period .Studies have shown that after mowing in autumn, 11 fall dormancy rate of alfalfa have the same trend of photosynthetic pigments. Photosynthetic pigment content of diffemt fall dormancy rate is no significant Thlorophyll content of different fall dormancy rate is negatively correlated with the length of sunshine. Carotenoid of different fall dormancy rate is positively correlated with the length of sunshine. Correlations are not significant. 11 fall dormancy rate of alfalfa leaf photosynthetic pigments have the same absorption spectrum and different photosynthetic pigment optical density analysis can be used the same method.更多还原