密度和空间布局种植方式对夏玉米穗位叶光合生理性状的影响

为探明夏玉米适宜种植方式的光合生理机制,采用裂区试验设计研究了种植密度(9.3万,8.1万,6.9万,5.7万株/hm~2)、空间布局(等行距1穴1株,等行距1穴3株和宽窄行1穴3株)以及它们的交互作用对夏玉米郑单958开花后不同生育时期(开花期、抽丝期、灌浆前期、灌浆后期和完熟期)净光合速率及其相关性状的影响。结果表明:宽窄行1穴3株能显著降低夏玉米开花期和完熟期穗位叶净光合速率,而8.1万株/hm~2密度下的净光合速率不受空间布局的影响;等行距1穴1株空间布局下,种植密度不会显著影响穗位叶净光合速率。种植密度、空间布局以及它们交互作用对类胡萝卜素含量影响显著。等行距1穴3株空间布局下,9.3万株/hm~2种植密度显著降低前3个观测时期类胡萝卜素含量,而6.9万株/hm~2在宽窄行1穴3株以及5.7万株/hm~2在等行距1穴1株空间布局下显著降低完熟期类胡萝卜素含量。种植密度、空间布局及其交互作用均对PSⅡ最大光化学效率无显著影响。综上可知,8.1万株/hm~2种植密度不受空间布局的显著影响,而等行距1穴1株空间布局不受种植密度的显著影响,均能保证夏玉米郑单958植株的净光合作用及其相关指标维持在较高水平。结果也为从光合物质基础和光合水分生理基础方面(色素含量、荧光特性、净光合速率和蒸腾速率)解释种植方式-光合产物源-产量库之间的关系提供了理论数据。

Effects of Planting Densities and Row Spacing Modes on Photosynthetic and Physiological Traits of Ear Leaves of Summer Maize

In order to include the photosynthesis mechanism of summer maize in proper planting mode,in this paper,a split-plot experiment design was used to study the impact of planting densities(93 000,81 000,69 000, 57 000 plants /ha),row spacing modes(one plant per spot with equal row,three plants per spot with equal row and three plants per spot with wide and narrow row)and their interaction effects on net photosynthetic rate and its rela-tive traits of a summer maize variety ZD958 at different growth stages(flowering stage,silking stage,earlier filling stage,later filling stage and full ripe stage).The results indicated that the row spacing mode of three plants per spot with wide and narrow row could significantly decrease net photosynthetic rate of ear leaves at flowering stage and full ripe stage.At the planting density of 81 000 plants /ha,the net photosynthetic rate was not associated with row spac-ing modes.Meanwhile,under the row spacing mode of one plant per spot with equal row,planting density did not significantly affect net photosynthetic rate of ear leaves.It was noteworthy that the carotenoid content was closely as-sociated with planting densities,row spacing modes and their interaction effects.Under the row spacing mode of three plants per spot with equal row,the planting density of 93 000 plants /ha significantly decreased carotenoid con-tent at the first three growth stages,while both the densities of 69 000 under the mode of three plants per spot with wide and narrow row and 57 000 plants /ha under the mode of one plant per spot with equal row could significantly reduce carotenoid content at the full ripe stage.It was also found that the maximum photochemical efficiency of PSⅡ was not influenced by planting densities,row spacing modes and their interaction effects.In general,the plant-ing density of 81 000 plants /ha was not closely associated with row spacing modes,which was similar with the rela-tionships between the row spacing mode of one plant per spot with equal row and planting densities.In these two cir-cumstances,the net photosynthetic rate and its relative traits could maintain relatively higher levels.Our results could also supply experimental evidences for explaining the relationships among cropping patterns,photosynthetic products source and yield pool based on photosynthetic matters and water physiology(pigment content,fluorescence character,photosynthetic rate,and transpiration rate).