Effects of Red and Blue Light ratio on Photosynthetic Characters of Cucumber Seedlings
Using the cucumber variety'Jinyou 365'as the test material,eight light quality treatments were set up:white light(W),monochromatic red light(R),monochromatic blue light(B),and different ratios of red-blue composite light(9R1B,7R3B,5R5B,3R7B,1R9B).The results indicated that red-blue light significantly affected the steady-state and dynamic photosynthesis of cucumber seedlings.Compared to red light,blue light plays a crucial role in enhancing the maximum photosynthetic capacity(Pmax)of cucumber seedlings,mainly by increasing the apparent quantum efficiency(AQE),the maximum carboxylation efficiency of Rubisco(Vcmax),the maximum electron transport rate(Jmax),the triose phosphate utilization efficiency(TPU),and the stomatal conductance(Gs).Under red-blue composite light treatments,AQE,Vcmax,Jmax,TPU,and Pmax increased with the rise in the proportion of blue light,with the 1R9B treatment achieving the highest maximum photosynthetic rate(Pmax).However,there was no significant difference between the 1R9B treatment and the 5R5B and 3R7B treatments.Additionally,an appropriate proportion of blue light(30%-70%)also increased the induction rate of net photosynthetic rate(A)during the transition from low to high light,and reduced the time required for the photosynthetic rate to increase by 90%(T90%A).The T90%A under the 1R9B treatment was significantly higher than that of the 7R3B,5R5B,and 3R7B treatments,indicating that excessive blue light can decrease the induction rate of photosynthetic rate.In summary,increasing the appropriate proportion of blue light can not only enhance the maximum photosynthetic capacity of cucumber seedlings but also accelerate the induction rate of photosynthetic rate,improving the dynamic photosynthetic capacity of cucumber seedlings.The 5R5B and 3R7B treatments resulted in the best maximum photosynthetic capacity and dynamic photosynthetic capacity for cucumber seedlings.
Cucumberred and blue lightsteady-state photosynthesisdynamic photosynthesis
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