基于结构方程模型的控水稻"需水量-光合量-产量"关系研究

水稻产量的形成是源库互作的过程,稻田水位的变化对水稻的源库关系有重要影响。该文使用2009、2010年,2年水位调控试验数据,通过计算水位调控水稻全生育期需水量和冠层总光合量,选取水稻群体质量因子(最大LAI、根冠比、株高、茎质量)和产量构成因子(有效穗数、每穗粒数、千粒重、结实率),利用结构方程模型综合分析了水位调控水稻需水量、光合量与群体质量及产量构成之间的关系,结果表明:水位调控水稻总需水量对各因子总效果大小(绝对值)的前三位依次为:千粒重(0.717)、有效穗数(0.650)、每穗粒数(0.459)。冠层总光合量对各因子总效果大小(绝对值)的前三位依次为:茎重(0.613)、最大LAI(0.437)、株高(0.437)。说明总需水量对产量的形成起重要作用,而冠层光合侧重于影响水稻群体发育状况。水位调控水稻"源-库"间相关系数为0.44,呈中度正相关关系。总需水量与冠层总光合量对产量的直接和间接效果值均为正值,总需水量对产量的总效果值(0.552)大于冠层总光合量(0.201),且这种影响主要来自间接作用(0.492),即对产量构成因子的作用。

Relationships of 'water requirement- photosynthesis- production' for paddy rice using structural equation modeling

Abstract: The yield formation of rice is affect by the relation between source and sink, and the variation of water level is important to relationship between source and sink. Under the water management of paddy rice, yield and population quality can be controlled effectively, which is important to the relationship between moisture and yield studies. Structural equation modeling (SEM) is a method of multivariate statistical analysis. Through structuring generalization of the theoretical models and path diagrams, causal relationships and effect value among the multivariable can be achieved. Based on source-sink theory of rice, this study analyzed the relationships of "water requirement-photosynthesis-population quality-production" for paddy rice under water level control using structural equation modeling method. Tests were implemented in the experimental station of Jiangning campus of Hohai University (Efficient Irrigation and Drainage and Environment of Agriculture Water and Soil of South Area Key Laboratory of The Ministry of Education) from May to October in 2009 and 2010. Those tests were carried out in fixed cubic lysimeters (28 with closed bottom and 2 without bottom) with specifications for the length × width × depth = 2.5m×2m×2m, and processing scheme of drought and waterlogging in different growth stages of rice was designed. Dynamic variation rule of water level in paddy fields and rice growth and physiological indexes were observed, rice water requirement during whole growth stages and total amount of canopy photosynthesis under water level control were calculated. Then, we chose some population quality indexes (maximum LAI, root-shoot ratio, plant height, stem weight) and yield components indexes (effective panicles, grains per panicle, 1000-grain weight, seed setting rate) as observation variable, and analyzed the relationships among water requirement, photosynthesis, population quality and yield components of rice under water level control using structural equation modeling method. The results showed that: the first three total effect value (absolute value) of total water requirement to the factors were 1000-grain weight(0.717), effective panicles(0.650), grains per panicle(0.459). And the fist three total effect value (absolute value) of canopy gross photosynthesis to the factors in order were stem weight (0.631), maximum LAI(0.437), plant height(0.437). It showed that total water requirement played an important role in yield formation, moreover, canopy photosynthesis focused on the effect of rice development status. Source and sink correlation showed moderate positive correlation with the coefficient of 0.44. Both the direct and indirect effects from total water requirement and canopy gross photosynthesis were positive. Total effect value (0.552) of total water requirements on yield is greater than the total canopy photosynthetic capacity (0.201), and the effect of total water requirement on yield came indirectly from the function of yield components factors.