The Effects On The Growth Of Hosta Cultivar Under Shading And Interactive Effects Of Nitrogen And Light Condition And Comprehensive Evaluation About Hosta Cultivar

Hosta plant belongs to Liliaceae perennial herbaceous flower.There are a lot of good characteristics such as rich varieties,unique appearance,long ornamental period,strong adaptability and shade tolerance and so on.It is a kind of excellent green vegetation under the forest and full of high ornamental value and garden application value.In this study,the botanical characteristics of Hosta plants from Shenyang botanical garden was observed in the northern region and the landscape evaluation model was constructed by combining the entropy AHP analytic hierarchy process,aim to choose excellent Hosta varieties which can adapt to the natural environment of north China.According to the actual growth condition,three kinds of varieties were selected for studying the diurnal changes of photosynthesis in order to explore their optical properties and light adaptability.The effects of shading,light and nitrogen on the development of three kinds of Hosta were studied under different shading(full light,transmittance 50%,30%,10%)and nitrogen application(2.5 g,5 g,7.5 g/pot)condition,aim to seek for the optimum growth conditions and nitrogen application rate.This research will provide theory directions for landscape application of Hosta plant.The results of the study were as follows:(1)40 species(species)Hosta were divided into four grades according to ornamental value combing the AHP method:Grade I(>4.0),there were 3 species(variety)with the highest ornamental value;Grade II(3.5-4.0),there were 12 species(varieties)with higher ornamental value;Grade ?(3.0-3.5),a total of 16 species(varieties);Grade ?(<3.0),a total of 9 species(varieties).(2)The Pn of 3 different speices Hosta showed two peak curves,10:00am and 16:00pm separately,the first peak was higher than the second one obviously,at 14:00pm,appearing photosynthesis "lunch break" phenomenon.The changing of Tr is similar to Gs,but opposite to Ci.The data of WUE arrived to maximum at 14pm.The correlation analysis showed that there was a significant negative correlation between Pn and Ci(p<0.01).Pn and Gs had a significant positive correlation(p<0.01),and the correlation coefficient between Pn and Gs was the highest.The LSP of 'Blue Angel' Hosta has the largest difference to LCP,with a greater range of light to adapt,the AQY of 'Paul's honor'Hosa reached 0.053?mol·m-2·s-1,with better light energy utilization.(3)The Pn values of the three kinds of Hosta changed to single peak in the shading treatment.The Pn value of 'Blue Angel' Hosta reached the maximum under the condition of 50%of the light,while the Pn value of 'Grand Tiara' Hosta and Hosta 'Paul's Glory' reached the maximum at 30%.3 kinds of Hosta LCP were less than 20,all have strong shade tolerance.Three kinds of Hosta are the growth of the indicators under the shade conditions.'Blue Angel' Hosta 50%under the conditions of the best growth,luxury crown Hosta and Paul's honor Hosta more suitable for 30%light conditions.With the increase in shade,parasite nutrition distribution and the underground part of the transfer to the ground part of the growth and development,increase leaf area,enhance photosynthetic capacity.The chlorophyll content of the three kinds of parasol decreased with the decrease of light intensity.No.1 Hosta and Paul's honor Hosta in the 30%light conditions,the largest chlorophyll content,luxury crown hairpin in 10%of the largest treatment.Chl.a/b value shows the opposite trend,indicating that Chl.b growth rate is greater than Chl.a,to enhance their ability to die on the blue,and are less than 2.3,indicating that three kinds of hosta are strong resistant varieties.There were no significant effects on the fluorescence index Fo,Fm and Fv/Fm of the three kinds of host hairs,and the Fv/Fm had a certain amplitude and the light conversion efficiency was improved.(4)The results showed that the three kinds of Hosta were more effective in the use of nitrogen under the condition of L2 light,and the demand was lower in L1 high light condition.No.1 Hosta in L1(50%light)-N1(2.5g/pot),luxury crown hairpin and Paul's honor Hosta in L2(50%light)-N2(2.5g/pot)treatment when the photosynthetic rate is higher Conducive to the accumulation of organic matter,promote growth and development.