Cultivar Evaluation And Chemical Preservation Of Cut-flower Freshness In Lotus (Nelumbo)

Lotus is a perennial emergent aquatic plant belonging to Nelumbo in Nelumbonaceae.Asian lotus(N.nucifera Gaertn.)is one of ten famous flowers with high ornamental values and has been widely cultivated in China.Compared to Thailand,India,Japan and other countries,lotus cut-flower has a long history in China but the studies related to which are rare,and also no evaluation for lotus cut-flower variety and standard of lotus cut-flower has been established before.In order to understand the people's demand for lotus cut-flower,screen the cultivars suitable for cut-flower production and extend vase life,a questionnaire analysis was conducted on lotus cut-flower using Analytic Hierarchy Process(AHP)to make a systematical assessment for lotus cultivars;the physiological index changes of fresh lotus flowers both in vase and at natural state were determined and compared;and the effect of anti-transpiration agentinitial on freshness-maintenance of lotus cut-flower was preliminarily evaluated.The main study results are as follows:1.The online and onsite surveys were conducted by a questionnaire based on the characteristics of lotus.It showed that the results of both online and onsite surveys were basically consistent.The most people are willing to buy cut lotus-flowers.On the ornamental characteristics,the red-green oval-conical or red ovoid-spherical flower buds,and semi-doubleor and double petalled,versicolor,bowl-shape flowers are preferred.The lotus flower with light fragrance is more welcome.In terms of purchase and usage,the most repliers prefer buying lotus cut-flowers alone(not together with other flowers)mainly used for indoor decoration.The most acceptable price is 5 to 10 yuan per flower.The short vase life and rare selling in the market are the major factors inhibiting the development of current lotus cut-flower market.2.The 159 cultivars(including wild population)of ornamental lotus were evaluated using AHP to construct an intergrative assessment system on lotus cut-flower.After the levels of 5 criteria and 18 indices were determined,the weights at all levels were decided through judgment matrix and consistency check calculation,and a quantitative evaluation was made on the weight of each influence factor.According to the opinions of both experts and the public,the evaluation standard was established based on the score assigned to each specific index.Thereafter,the lotus cultivars suitable for cut-flower production were screened.According to the intergrated score,the 17 high-quality cultivars of cut-flower lotus were selected.3.Under the natural and vase conditions,the physiological indices including malondialdehyde(MDA),soluble protein,soluble sugar,superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),and etc.were measured for a double-petalled N.nucifera ‘Zhongshan Hongtai'.The results showed that the contents of soluble protein and soluble sugar in lotus petals presented an overall decline trend with the increased vase time.Whereas,MDA content positively correlated to the aging degree,while SOD and CAT contents rose at the initial stage in vase and declined at the later stage.The variation of POD contents is relatively larger.4.Taking N.nucifera ‘Dasajin' as experimental material,the effect of the complex agent containing anti-transpiration agent and preservative(10 g/L sugar + 100 mg/L Calcium chloride + 100 mg/L Alum + 100 mg/L HQS)on freshness-keeping was evaluated.The result indictated that the fresh weight of cut lotus-flower could maintain and the vase life could be extended to some degree.Meanwhile,the soluble protein content was prevented from fast declince,and the rising of MDA and cytomembrane relative permeability were prohibited,and the activity of SOD and CAT was enhanced.