Effects Of LED Light Source On Survival Rate Of Tomato Grafted And Physiological Response Of Seedling

LED is mostly used in greenhouse light supplement,plant factory,tissue culture and other aspectsin agricultural production.However,there are few studies on the application of LED in Tomato Grafted Seedling.In order to select the LED light source suitable for promoting the grafting healing of tomato,the grafting experiments were carried out using‘Eggplant Anvil No.21’(S21)and‘Muscovy Anvil No.3’(S3)as rootstocks,mini tomatoes(Fb)and common tomatoes(Rf)as scion.Four kinds of grafted seedlings(Fb/S21,Fb/S3,Rf/S21,Rf/S3)were used as materials.Single-wave LED blue light(B,450 nm),red light(R1,630 nm;R2,660 nm),infrared light(I,735 nm)and composite LED white light(W1,W2,400-780 nm)wereusedtomake up LED light sources with different wave lengths and light intensity.The survival rate,seedling growth and physiological response of tomato grafted seedlings under different light supplement conditions were studied by using incandescent lamp as control(CK)to provide a reference for the selection of LED light source for industrial grafted seedlings.The main results are as follows:1.The survival rate of tomato grafted seedlings under different light sources was significantly different.The survival rate of four grafted seedlings was79.84-90.16%under the condition of B light supplement,which was higher than that of R1,R2 and I light supplement,but significantly lower than that of the CK,indicating that single-wave LED light source was not conducive to the grafting healing of tomato.Under the light supplement condition of compound light source(W1,W2,R2+I),the survival rate of four grafted seedlings was significantly higher than the CK or no significant difference with the CK.Among them,the survival rate of grafted seedling Fb/S21 were98.01%,99.18%,97.14%on W1,W2 and R2+I,the survival rate of the grafted seedlings Fb/S3were 99.54%and 98.41%on W1 and W2,the survival rate of grafted seedlings Rf/S3 was 91.93%on W2,which were significantly higher than the CK.The results showed that W1,W2,R2+I could be used in Tomato Grafting.2.The effects of different light sources on the growth of tomato grafted seedlings were significantly different.In the single wave LED light source,the plant height of four grafted seedlings increased by 8.7-10.1 mm under infrared light(I)and 0.367-0.467 mm under blue light(B),which were significantly higher than the CK and other single wave light sources,indicating that infrared light promoted plant height growth and blue light promoted stem diameter growth.In the compound LED light source(W1,W2,R2+I),the plant height of the grafted seedlings Fb/S21 and Rf/S21 increased by 8.33mm and 8.57mm respectively under R2+I light supplement,which were significantly higher than the CK,and there was no significant difference between the plant height growth and the CK under W1 and W2 light supplement;there was no significant difference between the plant height growth of the grafted seedlings Fb/S3 and Rf/S3 under R2+I light supplement and the CK under W1 and W2 light supplement.The stem diameter of grafted seedlings Fb/S3 increased by 0.433mm under W1 light supplement,which was significantly higher than the CK;the other grafted seedlings had no significant difference with the CK under compound LED light supplement.The results showed that R2+I light supplement could make the grafted seedlings of S21 grow in vain,and W1 and W2 light supplement had no significant difference with incandescent lamp.W1light supplement could increase the stem diameter of the grafted seedlings Fb/S3,which was beneficial to the strong seedlings.Subordination function analysis was carried out on the survival rate of tomato grafting and seedling growth index under different LED light supplementation conditions,and it was concluded that W2,R2+I and W1 supplementing light could be used for tomato grafting seedling supplementing light.3.The physiological responses of tomato grafted seedlings were compared under the light supplement of compound LED light sources(W1,W2,R2+I)were significantly different.The photosynthetic pigment content of grafted tomato leaves was 0.0446-0.0570 mg/cm~2 and 0.0189-0.0247 mg/cm~2,respectively,which were significantly higher than the CK.The content of chlorophyll a and carotenoid in grafted tomato leaves was not significantly different from the CK.The content of chlorophyll a and carotenoid in grafted tomato leaves was 0.0161-0.0166 mg/cm~2,significantly higher than the CK.The content of soluble protein in the stem of the grafted seedlings was 0.37-3.30mg/g FW,significantly lower than the CK.The content of MDA in the stem of the grafted seedlings:there was no significant difference between the stem of the grafted seedlings Fb/S21 and Fb/S3 and the CK on the 10th day of W1 light supplement;the stem of the grafted seedlings Fb/S3 and Rf/S3 on the 10th day of W2 light supplement was significantly lower than the CK,and there was no significant difference between the stem of the grafted seedlings Fb/S21 and Fb/S3 and the CK.The stem conductivity of grafted seedlings:W1 and W2 for10 days,the grafted seedlings Rf/S21 and Rf/S3 were significantly lower than the CK,the grafted seedlings Fb/S3 and Rf/S21 had no significant difference with the CK.The activities of pod,SOD and cat in the stems of grafted seedlings of mini tomato and common tomato were higher than those of the CK.The results showed that W1 and W2 light supplement could promote the photosynthetic pigment synthesis of grafted tomato leaves,but had no significant difference with incandescent lamp.The degree of stress response of grafted tomato seedlings was significantly lower than that of incandescent lamp.It can be seen from the analysis of membership function based on the comprehensive research results.The results showed that W1 and W2 could significantly improve the grafting survival rate of mini tomato,had no significant effect on the grafting survival rate of common tomato,had no adverse effect on the growth of grafted seedlings and photosynthetic pigment synthesis of leaves,had less stress on grafted seedlings than incandescent lamp,and was suitable for grafting healing and light supplement of tomato.W1 is more energy-saving than W2,and it is more beneficial to strengthen seedlings and promote the synthesis of photosynthetic pigment.W1 can be selected as the energy-saving light source of Tomato Grafting and healing room.