Effects Of End-of-day-far-red Light Treatment On The Growth Of Pumpkin,the Yield And Quality Of Asparagus Lettuce And Chrysanthemum

This study was aimed to understand the effects of growth,histiocyte morphologic and phytohormone levels of pumpkin seedlings under different doses of End-Of-Day Far-Red light(EOD-FR)treatment,so as to provide a theoretical basis for the application of far-red in agricultural industry.Research 1: Taken the pumpkin(cv.Japanese cedar)as experimental material,the growth state of hypocotyl’s histiocyte morphology and the contents of auxin(IAA),zeatin(ZT),gibberellin(GA3)and brassinolide(BR)were measured under 0(CK),2(T1),4(T2),6(T3),8(T4),10(T5)and 12(T6)mmol·m-2·d-1 dose far-red light treatments,respectively.The hypocotyl length and plant height of pumpkin seedlings were significantly increased by EOD-FR treatment,while there was no significant effect on the diameter,dry and fresh weight of pumpkin stem.Compared with the control group,the lengths of hypocotyl’s parenchyma cell of each treatment were significantly increased by 34.6%,20.7%,31.3%,25.6%,32.8% and 20.9%,respectively;the collenchyma’s thickness were significant increased by 19.6%,22.4%,21.2%,23.9%,19.6% and 28%,respectively.After EOD-FR treatment,the contents of IAA in roots of pumpkin seedlings significantly increased,and the contents of IAA,GA3 and ZT in hypocotyls,IAA,GA3 and BR in cotyledons,IAA and BR in euphylla were also increased.Through increasing the hormone levels under EOD-FR treatment,the histiocyte morphology could be changed,and the hypocotyl elongation could be increased.Research 2: In order to further explore the role of auxin under EOD-FR treatment mediated hypocotyl elongation of pumpkin,We used RNA-seq and metabolome to identify differential metabolites and genes in the hypocotyls of pumpkins.Here,integrated transcriptomic and metabolomic analysis of pumpkin hypocotyls revealed that the expression of auxin-related genes changed significantly after EOD-FR treatment,and the contents of the auxin biosynthetic precursors tryptophan and indole were also significantly higher.We found that pumpkin hypocotyl length,parenchymal cell size in hypocotyls,and plant IAA levels were significantly greater after EOD-FR treatment.This effect was counteracted by the application of the polar auxin transport inhibitor1-N-naphthylphthalamic acid.Our results show that auxin plays an essential role in EOD-FR-mediated hypocotyl elongation.Research 3: According to the former part,we designed new type of far-red supplementary lamp,it has the advantages of accurate spectrum,easy to use and light weight.We use asparagus lettuce and crowndaisy to verify the design of the far red light supplement lamp function.Uesd asparagus lettuce variety "Red leaf" and crowndaisy variety "Lobular" were used as experimental materials.We cultivated in greenhouse and treated with end-of-day far-red light.The results showed that the plant height of asparagus lettuce and crowndaisy increased by 17.9% and 19.2%,respectively.The fresh weight of the crowndaisy was significantly increased,but the dry fresh weight of the aboveground part of lettuce was significantly decreased.The content of soluble protein in asparagus lettuce and crowndaisy was significantly decreased after end of day far red,while the content of vitamin C and cellulose increased,and the contents of chlorophyll a,chlorophyll b and nitrate had no significant changes.These results indicate that end of day far red has potential application value for plant vegetable production and cultivation,but more experiments are needed to ensure the yield and quality of vegetables.