| Herbaceous peony (Paeonia lactiflora Pall.) is a traditional and popular flower in China, which has a long history of cultivation. With the growing sales in the international markets in recent years, it has become an emerging commercial flower. Protected cultivation has been the key way to supply herbaceous peony all the year round. This study was carried out on10varieties of herbaceous peony in greenhouse which were widely grown in the north of China. In this research, growth performances of10varieties cultivated in low-light condition were systematic observed and characters such as flower production, quality and etc. were evaluated; the changes on photosynthetic physiology, morphology structure and etc. were studied to inquire into the adaptation mechanism to low-light conditions; furthermore, indicators of physiology and morphology which were significant associated with the growth and flowering, were used for comprehensive evaluation models to build scanning system. Also, after comparing effects of three different over-summering managements on photosynthesis which were designed to solve the full-light photoinhibition, the full light cultivation with atomization was considered to be the most helpful for peony’s adaption from low-light to full-light.The main results of this research are as follows:1.After the examinations on growth performances and blossom characters of36peony varieties grown in field,10varieties which were’Zi Feng Yu’,’Tao Hua Fei Xue’,’Da Fu Gui’,’Tie Gang Zi’,’Chun Xiao’,’Qing Wen’,’Duo Ye Zi’,’Dong Jing Nv Lang’,’Wan Shou Hong’and’Dong Fang Hong’were selected preliminarily and shifted into greenhouse. The performance of10varieties showed significant difference under two cultivation conditions. Among them,’Da Fu Gui’and’Tao Hua Fei Xue’were selected as excellent varieties in flower production and quality under protected cultivation condition;2. The growth and blossom performances of10peony varieties tested in protected cultivation were found closely correlated with indexes such as the apparent quantum yield (AQY), the maximal photochemical efficiency of PSII (Fv/Fm), the maximum net photosynthesis rate under light saturation intensity, chlorophyll a/b and carotenoids contents. For instance, the Fv/Fm of’Tao Hua Fei Xue’ and ’Da Fu Gui’which had better growth and flower performances were greater than0.8, while, all the other varieties are less than0.8;3. After comparison difference of10peony varieties between cultivated in greenhouse and field, the ratio of18indexes (coefficient variation) were able to reflect the different acclimation capacity towards protected cultivation. The smaller coefficient variation was, the better growth and flower performances peony varieties showed;4. The photoinhibition happened in summer when shifting the peony varieties from greenhouse to full-light cultivation. High temperature and light intensity after14:00would cause the closure of stomata in leaves as well as the decline of the actual quantum efficiency in PS Ⅱ. The varieties which were badly acclimated in greenhouse suffered worse photoinhibiton. In full-light condition at14:00, net photosynthetic rate of ’Tie Gan Zi’was only1μmol·m-2·s-1while ’Da Fu Gui’had4μmol·m-2·s-15. Providing shading treatment for varieties in full-light can avoid the occurrence of light inhibition, however the net photosynthetic rate of leaves was also restrained. Full light cultivation with atomization can reduce leaves’heat and increase stomata conductance which was capable to ease the extent of light inhibition. And also it can help peony’s leaves to recover from it in a shorter time. The net photosynthetic rate of recovered leaf was higher than shading treatment which was more benefit for growth accumulation after flowering;6. Correlation analysis on indicators of physiology and morphology and growth performances demonstrated that10of them had significant positive correlation with growth and flowering of herbaceous peony while9were significant negative correlated. Analytic hierarchy process has been considered to be the best due to that sequencing of different peony varieties most closely correlated with their actual growth observation.In summary, this research proposed a protocol for peony varieties scanning in protected cultivation:first step is to investigate in field. Varieties that with better growth performance and blossom characters were selected using9indexes can be tested in protected cultivation; secondly, after cultivating annual plant division in greenhouse for disease resistant test,9indexes which reflect light use efficiency as well as9indexes that reflects acclimation capacity towards protected cultivation were measured during growing season in first year; third step is after ruling out weak disease resistant ones, other varieties were sequenced using28index through analytic hierarchy process to determine which varieties grew better in protected environment. This protocol combined with protected cultivation experience can select varieties suitable grown in greenhouse efficiently. |
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