LED红蓝光质比和叶面锌肥种类对生菜生长、品质及矿质元素吸收的影响OA

To explore the effects of different LED red and blue light quality ratios and foliar zinc fertilizer types on the growth,quality and mineral element absorption of hydroponic lettuce under artificial light plant factory conditions,'Italian non-heading lettuce'(Lactuca sativa L.)was used as the test material.Three treatments were set up with LED red and blue light quality ratios of 3∶1(high red light,3R1B),1∶1(equal red and blue light,1R1B),and 1∶3(high blue light,1R3B),all with a light intensity of 200 μmol/(m2·s).Three types of zinc fertilizers,namely zinc sulfate(ZnSO4),nano-zinc oxide(nano-ZnO),and zinc glycinate(ZnGly),were foliar sprayed at a concentration of 1.54 mmol/L,with deionized water(ddH2O)spray as the control(CK).The results showed that:1)When the same type of foliar zinc fertilizer was sprayed,with the increase of the blue light ratio,the fresh weight,dry weight and plant height of the lettuce above ground gradually decreased;while the contents of chlorophyll a,chlorophyll b and total chlorophyll in the leaves gradually increased.Compared with 3R1B,the contents of chlorophyll a,chlorophyll b and total chlorophyll in the 1R3B treatment increased by an average of 30.9％,36.5％and 32.1％,respectively.The contents of soluble sugar,soluble protein,flavonoids and total phenols also significantly increased,with an average increase of 28.6％,24.1％,107.2％and 89.3％,respectively.2)Under the same light quality(1R1B),the fresh weight and dry weight of the aboveground and underground parts of lettuce in the nano-ZnO treatment were significantly higher than those in the ZnSO4 and ZnGly treatments.Among them,the fresh weight and dry weight of the aboveground part of lettuce in the 3R1B treatment with nano-ZnO were 4.4 and 1.9 times higher than those in the CK treatment,respectively.Compared with CK,the foliar spraying of the three types of zinc fertilizers could significantly increase the nitrate content in lettuce,while the contents of soluble sugar and soluble protein decreased.Under 1R1B,the Zn content in the leaves of lettuce sprayed with the three types of zinc fertilizers was significantly higher than that in the CK treatment.Under 1R1B,the Zn content in the leaves of the nano-ZnO treatment was 41.4 times that of the CK treatment.However,the contents of Mg,Mn and Fe in the leaves were significantly reduced by 68.3％,73.2％and 59.7％,respectively.3)Meanwhile,the interaction between the red and blue light quality ratio and the type of foliar zinc fertilizer could significantly affect the fresh weight and dry weight of the above-ground leaves,the fresh weight and dry weight of the underground roots,plant height,root length,as well as the contents of nitrate,soluble sugar,soluble protein,flavonoids,total phenols,Ca,Mg,Zn,Mn,Fe and B.Therefore,under artificial light plant factory conditions,the high blue-light sources can significantly improve the pigment and quality indicators of lettuce,while the high red-light ratio can significantly increase the yield of lettuce.The yield and Zn content of lettuce foliar sprayed with nano-ZnO were higher than those of other zinc fertilizers,and the effect was better under high red-light ratio.Moreover,foliar spraying of nano ZnO could effectively alleviate the antagonistic effects of Zn ions on Ca,Fe and Mn mineral ions.