Photosynthetic Spatial And Temporal Variation Analysis Of Wheat And Maize In The North China Plain Crops

Crop photosynthesis is an important way of promoting the accumulation of organic matter, the objective of this paper is to study photosynthetic characteristics under the time and space distribution to increase efficiency of solar radiation and provide effective theory basis of measuring the crop photosynthesis.The experiment was conducted in the Northern China plain.Photosynthetic physiological characteristics under the time and space distribution were measured using LI-6400 portable photosynthetic system in a typical winter wheat-maize rotation from October 2014 to October 2015.Results showed that:1.Using the right Angle hyperbolic model of winter wheat in five different irrigation treatment of different canopy light response curve fitting, the wheat of different canopy leaf net photosynthetic rate increases as the light intensity, while the upper blade is the largest. The leaf net photosynthetic rate under different irrigation treatment is not affected, also, presents the upper wheat leaf light ability strongest.2.By the right Angle hyperbolic model to fit the light response curve of summer corn blade at different period and different spatial distribution, net photosynthetic rate at different position (horizontal) follows light radiation grower,and the middle leaves is greater than stem leaves and slightly leaves.Net photosynthetic rate at different canopy (vertical) follows light radiation changing, and the upper leaves is larger than the middle and the lower leaves. Net photosynthetic rate of the sun leaf at different canopy win the shade leaf.While the light intensity is saturated state, the sun leaf closed porosity, net photosynthetic rate below shade leaf.3. The diurnal variation of Pn and Tr of winter wheat'leaves demonstrated larger fluctuation and the wave range were around 10:00 to14:00. Net photosynthetic rate, transpiration rate and water use efficiency'average order of winter wheat at different canopy are the upper> the middle> the lower.It indicates that canopy photosynthetic ability is different following vertical space with different height under the condition of light radiation evenly, also, the more to the lower leaf, the leaf age, the greater the photosynthetic capacity is weak.