| LED is a new type of light source with obvious effects in protected vegetable cultivation.But the energy consumption of the light source is still large during operation.Making full use of lighting and changing lighting patterns to improve energy and resource utilization is important ways to reduce costs.Therefore,the paper syudies the effects of daily light integral?DLI?on the growth of tomato seedlings under different LED intermittent lights.In this experiment,tomatoes were used as a material.And five different DLI treatments about9.72,12.96,16.20,19.40,22.68 mol·m-2·d-1 were set under the condition of suitable environment and sufficient water and fertilizer.At the same time,the effects of long period intermittent light and short period intermittent light on the growth of tomato seedlings by using continuous light as the control were studied,and the growth simulation model of tomato seedlings based on cumulative light quantity was constructed to determine the optimal LED light mode,in order to achieve high yield and quality,energy saving.it finally provides theoretical and technical guidance for the growth of tomato seedlings under this condition.The main findings are as follows:1.The effects of different DLI treatments on tomato seedlings growth,photosynthetic characteristics,and energy-saving indicators are significantly different.Under the light quality of 3R1B?The ratio of red to blue is 3:1?,with the increase of DLI,the plant height,stem thickness and leaf area of tomato seedlings all increased and then decreased,The maximum value was reached at T3?DLI = 16.20mol·m-2·d-1?,compared with T1,plant height and leaf area increased by 27.72% and 10.05% respectively,both reaching significant difference levels.And the dry weight increased and then remained unchanged.Besides,the Pn of T3 was significantly higher than other treatments,and increased by 24.93% compared with T1.At the same time,the photosynthetic pigment content and energy saving effect of T3 were better than other treatments,it is concluded that the DLI suitable for tomato seedlings growth is16.20mol·m-2·d-1,when greater than this value,it is will be affected by photosuppression.2.After long-term intermittent light treatment of tomato seedlings,it was found that compared with CK?continuous light?,the plant height and dry weight of each treatments all decreased,and compared with CK,the dry weight of T1,T2 and T3 decreased by 13.29%,14.69% and 11.19%,all reached the level of significant difference.Meanwhile,Pn,Gs and Tr of intermittent light treatment were significantly lower than CK.The PCE and LUE of CK are also significantly better than other treatments.This indicated that although long periodintermittent light could make tomato seedlings grow normally,it couldn't save resources to ensure quality.3.After short-period intermittent light treatment of tomato seedlings,it was found that,under the same DLI,short-period intermittent light without increasing energy consumption,compared with CK,the leaf area of tomato seedlings increased by 9.34% and reached a significant level,the seedling index increased by 5.71%,the photosynthetic rate increased,and its growth condition also showed a downward trend with the decrease of the short-duration intermittent light duty cycle.Therefore,it can be concluded that under the same DLI,short-period intermittent light will improve the seedling quality of tomato seedlings without increasing energy consumption,which can be used in actual production.4.In this test,a growth model of tomato seedling plant height,stem thickness and total dry weight based on accumulated light was constructed.The correlation formula of plant height was y = 1.0652x-0.0911,and the correlation formula of stem thickness was y =1.1049x-0.2686,all of which showed a linear correlation.The correlation of total dry weight is y = 0.248e0.006x,which is in the form of an exponential equation.And the test results of the models show that each model can better simulate the growth morphology and dry matter accumulation of tomato seedlings. |
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