Study On The Effects Of Different Light Quality On The Photosynthetic Characteristics And Active Ingredient Of Asarum

Seven light treatments were set up to study the effects of light quality on photosynthetic characteristics and active ingredients synthesis of Asarum heterotropoides var.mandshuricum.Subsequently,the growth and photosynthetic physiological indexes,the activity of secondary metabolite synthetase and the content of active ingredients of Asarum heterotropoides var.mandshuricum under each light treatment were studied.Through this study,we hoped to provide a theoretical basis for reasonable light adjustment measures in Asarum heterotropoides var.mandshuricum planting and the development of high light efficiency cultivation.The details were as follows:（1）In order to reveal the effects of light quality on the growth and photosynthetic characteristics of Asarum heterotropoides var.mandshuricum,seven colorful films treatments were provided to five-year-old plants after germination in May respectively.Under light quality of white film,the leaves of Asarum heterotropoides var.mandshuricum grew well before July,and withered gradually from mid of July,however,Plants were well-grown under other light quality.Mature leaf length and width,petiole length and petiole diameter of Asarum heterotropoides var.mandshuricum under light quality of green film were all larger than those grown under other color films light conditions’and their order was Ll _GF>Ll _PF>Ll _YF>Ll _RF>Ll _BN>Ll _BF.The annual growth rate of root under light condition of green film was larger than other film conditions’and the root growth rate’s order was 63.3%_GF>60.0%_PF>56.3%_YF>43.3%_RF>35.3%_BN>28.3%_BF.From June to September,photosynthetic pigment content,daily average net photosynthetic rate and specific leaf weight of leaves under light condition of green film or purple film exceeded those under other films condition’.Under each films light condition,net photosynthetic rate was negatively correlatted with the ambient temperature and extremely negatively correlated with intercell CO₂（P<0.01）,however,transpiration rate was positively correlated with the ambient temperature（P<0.01）at four stages.Activities of superoxide dismutase and catalase of leaves grown under light condition purple film were highest among seven films treatments,whereas,peroxide activity of and malondialdehyde content of leaves under light condition of green film exceeded others.Noteworthly,only in July,malondialdehyde content of leaves under light condition of white film higher than others.From June to September,activity of catalase decreased gradually,while,activity of superoxide dismutase and the content of malondialdehyde increased at first and decreased later.Besides,activity of peroxide increased gradually.To sum up,light condition of green and purple flim are beneficial to the growth of Asarum heterotropoides var.mandshuricum.To sum up,light condition of green and purple film were beneficial to the growth of Asarum heterotropoides var.mandshuricum.（2）Under different light quality conditions,the activity of 3-deoxy-D-arabinoheptanulose-7-phosphate synthase（DAHPS）was the highest in leaves,followed by petioles and the lowest in roots during June to September.Activity of DAHPS in roots was the highest in July and the lowest in September with the trends of increasing firstly and decreasing later.Activity of DAHPS in petioles was the highest in September with showing an increasing trend.Activity of DAHPS in leaves was the highest in August and the lowest in September with the trends of increasing firstly and decreasing later.Under different light quality conditions,Phenylalanine ammonia lyase（PAL）activity in roots and petioles decreased from June to September.PAL activity in leaves decreased firstly,then increased,and later decreased.PAL activity of root was higher than that of petiole and leaf.PAL activity under light condition of purple mulching film was higher than those under other light conditions.From June to September,Activity of cinnamic acid-4-hydroxylase（C₄H）in roots decreased first,succeeding increasing,and then decreased later.However,its activity in petiole and leaf was increased firstly and decreased later.Activity of C₄H was the highest in August and the lowest in September under all kinds of light quality.C₄H activity in leaves was higher than those in roots and petioles,from June to July,Activity of C₄H in roots,petioles and leaves was C₄H_PF>C₄H_GF>C₄H_YF>C₄H_RF>C₄H_BN>C₄H_BF>C₄H_WF,while from August to September,activity of C₄H in roots,petioles and leaves was C₄H_PF>C₄H_GF>C₄H_YF>C₄H_RF>C₄H_BN>C₄H_BF.Under different light quality,4-coumaric acid coen-zyme A ligase（4CL）activity in different parts of the plant increased firstly and decreased later from June to September.4CL activity was the highest in August whereas the lowest in September,Aactivity of 4CL under light condition of purple mulching film was the highest.During the 4-month growth period,the activities of DAHPS,PAL,C₄H and 4CL in different parts of plants under light condition of purple mulching film were higher than those under other filter films,notably,the light quality condition under the purple mulching film is helpful to improve the enzyme activity for the synthesis of precursors of Asarum heterotropoides var.mandshuricum volatile oil such as phenylalanine,cinnamic acid and p-coumaric acid.（3）Under different light quality conditions,the contents of asarinin,volatile oil and alcohol soluble extract in roots and rhizomes collected in July were significantly lower than those collected in September.In July,the content of alcohol soluble extracts in the aerial parts of Asarum heterotropoides var.mandshuricum under different light quality was26.6%_PF>25.3%_GF>22.2%_YF>21.9%_RF>18.2%_BF>17.5%_BN,with significant difference（P<0.05）.In September,alcohol soluble extracts in the aerial parts of Asarum heterotropoides var.mandshuricum under different light quality was 27.8%_PF>26.4%_GF>23.5%_YF>22.7%_RF>18.8%_BF>18.5%_BN,with significant difference（P<0.05）.In July,alcohol soluble extract in the underground part of Asarum heterotropoides var.mandshuricum growing different light quality was 16.8%_PF>16.6%_GF>11.1%_BN>10.1%_RF>10.0%_YF>7.71%_BF,with significant difference（P<0.05）,And,in September,alcohol soluble extract in the underground part of Asarum heterotropoides var.mandshuricum under different light quality was 18.2%_PF>18.4%_GF>13.5%_YF>13.2%_RF>2.1%_BN>8.0%_BF,with significant difference（P<0.05）,and the contents of which was 1.02 to 1.35 times of those in July.In addition,the content of Asarinin in the aerial part of Asarum heterotropoides var.mandshuricum under different light quality was less than 0.035%in July and September,the content of Asarinin in root and rhizome was more than 0.268%,which was about 10 times of that in aerial part.Aristolochic acid I was detected in the aerial parts of Asarum heterotropoides var.mandshuricum under different light quality in July and September,the contents（μg/g）was92.40_BN>94.99_GF>81.41_RF>89.85_BF>88.84_YF>88.76_WF>71.84_PF,which was about twice of those in September.In July,Aristolochic acid I was only detected in the roots and rhizomes whose plants grown under the light condition of purple mulching film,and the content was 10.84μg/g,however,Aristolochic acid I was not detected in roots and rhizomes whose plants growing under the other five light quality conditions,Aristolochic acid I was not detected in roots and rhizomes collected in September growing under six light qualities.The content of volatile oil（m L/g）of roots and rhizomes collected in July was1.87%_GF>1.73%_PF>1.72%_YF>1.53%_RF>1.47%_BN>1.39%_BF,with significant difference（p<0.05）.The content of volatile oil of roots and rhizomes collected in September was 2.16%_GF>2.09%_PF>1.80%_YF>1.68%_RF>1.55%_BN>1.46%_BF,with significant difference（P<0.05）,and the content of roots and rhizomes was about 10 times higher than that in aerial part,in addition,the content of September’s was significantly higher than that of July’s（P<0.05）.The components of volatile oil in roots and rhizomes of Asarum heterotropoides var.mandshuricum under different light quality in July were as follows:46varieties _PF>44varieties _BN>43varieties _GF>38varieties _BF>37varieties _RF>32varieties _YF,among these,there were 13 components with relative content more than 1%,including pinene,（-）-β-pinene,phellandrene,3-carene,2,6,6-Trimethyl-2,4-cycloheptadien-1-one,safrole,myristicin,2-isopropylimidazole,borneocamphor,3,5-dimethoxytoluene,methyleugenol,3,4,5-trimethoxytol uene,pentadecane.The volatile oil components of root and rhizome under different light quality in September were as follows:49varieties _GF>48varieties _YF>47varieties _RF>45varieties _PF>44 varieties _BF=44varieties _BN,there are 17 components with relative content more than 1%,including:Pinene,β-Pinene,3-carene,2,6,6-Trimethyl-2,4-cycloheptadien-1-one,borneo camphor,3,5-dimethoxytoluene,safrole,methyl eugenol,3,4,5-trimethoxytoluene,5-tertbutyl pyrophenol,myristicin,pentadecane,2-carboxystyrene,methyl1,3-benzoxazole-5-carboxylate,3,4-（methylen-edioxy）phenylacetone,elemicin,kakuol,Among them,3,4-（methylenedioxy）phenylacetone,elemicin,kakuol were unique to the volatile oil in September,while,the components such as methyl eugenol,2,6,6-Trimethyl-2,4-cycloheptaden-1-one and safrole were commonly found in the volatile oil in July and September.In conclusion,the relative contents of the main components of Asarum heterotropoides var.mandshuricum volatile oil were significantly different under the different light quality conditions.