Study On Light Adaption And Interactions Of Nitrogen With Light Of Three Kinds Of Colorful Hosta

The Hosta Plants are Perennial herbs of Liliaeae, which have highly ornamental values of leaves and flowers,the Hosta have been planted in Europe and America countries for many years,Especially in recent years,some of mosaic or color leaves varieties is very popular in breeding or application of abroad,so it is important that sustainable development and utilization of Hosta plants.This test material is three kinds of Hosta introduced from abroad:Hosta ’Golden Tiara’,H.’Gold Edger’and H.Sieboldiana’Gold’.First is research on its natural lighting conditions Photosynthetic characteristics,Light response curves were fitted using a new YE Zi-piao model,and light saturation point and light compensation point were obtained,make sure of the light adaptability of Hosta; second is to analyze the optimal light range of three kinds of Hosta. Last is research on the interactions of nitrogen with light of three kinds of colorful Hosta, make sure of the reasonable nitrogen supply in Suitable light intensity. In order to provide scientific basis for introduction cultivation and landscape application of Hosta.The main conclusions of this study are as follows:l.The curves of diurnal variation in the net photosynthetic rate had double-peaks, the net photosynthetic rate peaks were detected at10:00am and16:00pm;depression of photosynthetic rate at noon was mainly due to non-stomatal limiting factors; correlation analyses showed that the net photosynthetic rate of three Hosta had significantly negative correlation with intercellular CO2(P<0.05),the net photosynthetic rate of H.’Golden Tiara’ had significantly positive correlation with transpiration rate(r=0.780*,P<0.05),the net photosynthetic rate of H.’Gold Edger’ and H. Sieboldiana’Gold’had significantly positive correlation with photosynthetic active radiation(r=0.803*,r=0.762*,P<0.05)and had no significant correlation with other factors.The light saturation point and light compensation point were between776.24-802.580μmol-m-2·s-1and17.50-19.68μmol·m-2·s-1,respectively. The three Hosta showed typical characteristics of Cultivation C3plant, being strong in tolerance to shade,H.’Golden Tiara’ have relatively wide adaptability to the light environment, and water use efficiency is opposite higher and cultivation is easily survived,but H.Sieboldiana’Gold’and H.’Gold Edger’ require a relatively strict environmental.2.The curves of diurnal variation in Pn,Gs,Tr and Ci had double-peaks,which H.’Golden Tiara’ and H.Sieboldiana ’Gold’in70%shading treatment,H.’Gold Edger’in90%shading treatment all achieve the best level about Pn, In this case, Fv/Fm,φPSll and qP of three kinds of colorful Hosta reached a maximum,and both90%and in full light treatments decreased the net photosynthetic rate.Adequate shading treatment can increase three kinds of colorful Hosta leaves length,width and plant height, to increase the above-and below-ground biomass of colorful Hosta.The growth of H.Sieboldiana’Gold’and H.’Golden Tiara’were the best under the70%shading treatment,50%shading treatment was more favorable to the dry matter accumulation of H.’Gold Edger’,there were significant difference(P<0.05)compared with full light, It is thus clear that adequate shading treatment is three kinds of colorful Hosta growth better environmental conditions,the shade-tolerance ability of H.’Golden Tiara’ and H.Sieboldiana’Gold’ are better than H.’Gold Edger’.The content of total chlorophyll increases along with strengthen shade,which H.’Golden Tiara’ in70%shading treatment,H.’Gold Edger’and H.Sieboldiana’Gold’ in90%shading treatments all achieve the best level about the chlorophyll content,the Chl.a/b was the lowest;the leaves of three kinds of colorful Hosta Chl.a/b content was lower than2.3under all light conditions, the chlorophyll content accord with shade-tolerance plant chlorophyll content change trend,this shows that three kinds of colorful Hosta had very strong adaptability to low-light environment,they are are the strongest shade-tolerant plants.Therefore,they were excellent ground cover plant, worth for popularizing and applying.3. Three kinds of colorful Hosta of leaf photosynthetic rate and chlorophyll fluorescence of the surrounding environment changes in response have been studied in the treatment of the two kinds of light intensity and four levels of nitrogen.The results showed that under the conditions of light intensity L1(shade50%) and L2(shade70%),three kinds of colorful Hosta of leaf chlorophyll a,chlorophyll b,total chlorophyll and carotenoid increased first and then decreased with the increase of nitrogen supply,the turning point in the level of nitrogen treatments were in N2(9.6g/basin) and N1(3.2g/basin) respectively;the Pn and WUE in three kinds of colored Hosta leaves was significantly increase of nitrogen supply;Which in the L1conditions,the N2treatment on the fluorescence parameters of the H.’Gold Edger’ is significant, H.’Sieboldiana Gold’and H.’Golden Tiara’ reached a maximum under the light intensity L2and nitrogen level N1treatment,the Light intensity and nitrogen supply had a significant interaction on the Fv/Fm and qP (p<0.05).Research shows that the combination of L1(light intensity) and N2(nitrogen level),L2(light intensity) and N1(nitrogen level) could improve the degree of utilization of light energy and increased the amount of dry matter accumulation in three kinds of colorful Hosta.