Effects Of Photoperiod On The Growth And Development Of Chinese Kale And Analysis Of Related Genes

Chinese kale(Brassica alboglabra L.)with yellow flowers,belonging to Cruciferae Brassica annual or biennial vegetable,is cultivated specifically in Fujian province.The main edible organs are tender stems and leaves.At present,the research on the growth and quality of Chinese kale with yellow flowerswas limited.In the production of vegetables including Chinese kale by hydroponics,illumination conditions and nutrient formulas are limiting factors.In this paper,Fuzhou Chinese kale with yellow flowers were usedto study the effects of hydroponic formula and photoperiod on its growth and quality.In view of the important role of cryptochrome(CRY)in photomorphogenesis,we obtained CRY related gene sequences,analyzed theirbioinformatics,and determinedthe expression levels under different photoperiods.1.Selection of nutrient formula solution for Chinese kaleChinese kale were cultivated 30 days in seven different nutrient solutions(F1:SCAU formula A;F2:SCAU formula B;F3:1/2 leaf formula of Hoagland and Amon;F4:French National Agricultural Research Institute formula for acid;F5:French National Agricultural Research Institute formula for neutral;F6:Japan Yamazaki Formula 1;F7:Japan Yamazaki formula 2).The results showedthat Chinese kale could grow normally under all the formulaswith different nutrient solution,while the morphology of Chinese kale were different among the treatments.The numbers of leaves were mostunder F6 and F7 withfive leaves,and the others had only four leaves;Plant height is the highest in F5 and F6 formula,the minimum is found in F3;Plant had the highest width in F7,followed by F2,F4 and F6,with a minimum in F3;The largest stem diameter and biological weightwere found in F6,witha minimum in F3.Root lengthwas the longest in F2 and F6,and the shortest was F1;In terms of root system,the overall situation of F6 is better than that of Chinese kale under other treatments.The results showed that the F6 formula in each index had advantages and was selectedas the most suitable hydroponic formula for the growth of Chinese kale,namely Japan Yamazaki Formula 1.2.The influence of photoperiod on the growth and development Chinese kaleChinese kale in two combined light condition(white light W;red-blue light RB)under different photoperiodic treatments(long sunshine 16 L/8 D;mid sunshine 12 L/12 D;short sunshine 8 L/16 D).With the extension of illumination time the fresh weight,crown width,and stem diameterof Chinese kale were increased.The changes of plant height were related to the ratio of combined light.Under white light,the plant height increased with the extension of light illumination time,but the plant height under red-blue light showed no correlation with photoperiod.Under different types of photoperiods,the total root length and root surface area of Chinese kale were increased.All the three photoperiods did not destroy the PSII reaction center,and the qN value has no differences,indicating that the damage of the blue light was small,and the heat dissipation did not increase greatly.After comprehensively measuring various indexes,the photoperiod suitable for the growth of Chinese kale under LED conditions was W16 L/8 D.3.The influence of photoperiod on the nutritional quality of Chinese kaleUnder different photoperiods,content of glucosinolates and polyphenols were analyzed in Chinese kale.The results showed that the aliphatic and indolic glucosinolates has no response to the photoperiod change.Unlike the glucosinolates,photoperiod does affect the accumulation of polyphenols in Chinese kale,and W16 L/8 D is more suitable for the synthesis of polyphenols than RB16 L/8 D.The antioxidant ability of Chinese kalewas evaluated by ABTS,DPPH,and FRAP.ABTS and DPPH mainly reflect the ability of plants to scavenge free radicals,and FRAP method mainly reflects the reductive ability of ferric ions in plants.The results showed that prolonging the illumination time could improve the antioxidant capacity of Chinese kale.4.Bioinformatic analysis of CRY genes in Chinese kale and their expression levelThere were one CRY1 genes,two CRY2 genes and three CRY3 genes in Chinese kale.Bioinformatic analysis showed that CRY1 and CRY2 were localized in the nucleus and involved in the morphogenesis of plants.CRY3 was localized in chloroplasts and mitochondria and its function was not clear.The expression levels CRY1 were the highest in 12 L/12 D,may be because short-time light illumination can promote CRY1 expression while long-timelight illumination would inhibit its expression.The expression of CRY2 showed the opposite trend under white and red-blue photoperiod.The expression level of CRY2 in white photoperiod increased with theextension of the light illumination,but opposite in red-blue photoperiod.This was consistant with the height changes under different photoperiods.