| Dendrobium catenatum is a kind of traditional Chinese herbal medicine,which has the functions of enhancing immunity,resisting tumor,nourishing yin and clearing heat,benefiting stomach and promoting body fluid.Due to over exploitation and habitat destruction,wild D.catenatum resources have been depleted.Since entering the new century,with the continuous breakthrough of D.catenatum cultivation technology,the rapid industrial development,emerged in different cultivation modes,effects of cultivation on growth and product quality of D.catenatum has become the focus of attention.In this paper,the C13 group was used to study the variation law of phenological period,morphological characteristics,functional components and microstructure of D.catenatum in three cultivation environments.There are three different cultivation conditions including rock epiphytic cultivation,pear epiphytic cultivation and pot cultivation.The results are as follows:1.The cultivation environment significantly affected the phenology and morphology of D.catenatum C13.There were significant differences in temperature and humidity between different cultivated environments.The ambient temperature of the pot cultivation was significantly higher than that of rock epiphytic and pear epiphytic.The environmental conditions were as follows:7.3 ? ~ 44.3 ?,-13.6 ? ~ 43.1 ?,-9.3 ? ~ 48.1 ?,the temperature difference between day and night in the field is obviously higher than that of facilities.There is a significant negative correlation between the change of air humidity and the temperature.The higher the temperature is,the lower the relative humidity is.In summer,the moisture of the epiphytic and the pear is much less than that of the facility.Therefore,the field cultivation of D.catenatum varieties require a higher resistance to low temperature and high temperature capacity,higher capacity of low humidity.D.catenatum C13 can grow normally under different cultivation conditions,but the phenology is closely related to the temperature change.The germination and flowering time of the planted D.catenatum were about 15 days ahead of the rock epiphytic and pear epiphytic,The growth of D.catenatum are not related with temperature.The cultivated environment significantly affected the length,root distribution,leaf and stem color and flower size of D.catenatum C13.The length of the sprouts of D.catenatum was 18.60 cm,10.66 cm and 6.56 cm,respectively.Pot cultivation D.catenatum root system upright down,most of the barbed in the matrix,root systemfrom rock epiphytic D.catenatum is particularly developed,the root is flat,close to the wall to the surrounding spread,the root occasional bifurcation,root of pear epiphytic most bent into the pear tree bark.The stems of the pot cultivation D.catenatum are elongated and green,leaves are dark green,and the biennial leaves can be retained to the winter.Length and width of rock epiphytic and pear epiphytic annual leaves is significantly less than the pot cultivation.The adorable biennial stem and leaf color was purple,leaves fall off in June.pot cultivation flower size,petal length and width are respectively 33.8 mm,16.50 mm,4.73 mm,was significantly higher than that of rock epiphytic and epiphytic pear.2.Effects of Cultivation Environment on the microstructure of D.catenatum.The leaf thickness of pot cultivation,rock epiphytic,pear epiphytic were 374.64 ?m,420.56 ?m,397.01?m,respectively.The thickness of the epidermis was 30.36 ?m,39.89 ?m,38.20 ?m,and the thickness of mesophyll was 306.73 ?m,374.20 ?m,352.09 ?m,the thickness of the lower epidermis was 13.79 ?m,14.36 ?m,14.62 ?m,the circumference of the stomata was 137.50 ?m and 132.89 ?m,128.66 ?m;the average stomatal density was 102.35,70.53 and 53.48,respectively.Compare with potted cultivation,D.catenatum from rock epiphytic cultivation and pear epiphytic cultivation showed the following characteristics in the microstructure: the upper epidermis became thickner,the epidermal hair in the epidermis became denser,stomatal showed smaller and denser,the cell wall of exodermis,endoderm and medulla became thicker,the cell of velamen,exodermis,endoderm and medulla were smaller and arranged more closely,D.catenatum C13 in the field of adversity showed leaf thickening,upper epidermis thickness increases,the lower epidermis epidermis tufts,stomatal small and dense and root structure changes,is conducive to enhance the role of insulation,reduce water transpiration,reduce the light in the mesophyll,improve the water use efficiency and maintain photosynthetic efficiency,which reflects the adaptability of D.catenatum C13 to low temperature,high temperature,strong light and low humidity environment in the field.3.The growth environments also significantly influenced Contents of polysaccharides and alcohol-soluble extracts in D.catenatum C13.Contents of polysaccharides and alcohol-soluble extracts in Perennial and three-year-old D.catenatum were higher than those of the facility,Contents of polysaccharides and alcohol-soluble extracts in D.catenatum from rock epiphytic were the highest.The contents of polysaccharides in Perennial and three-year-old D.catenatumwere 37.44% and 36.33%,respectively,which were 4.47% and 8.90% higher than those of the potted plants.The content of alcoholic soluble components reached 11.58% and 14.28%,respectively,which was 3.27% and 2.45% higher than that of the facilities.The cultivation environment also affects the components of the polysaccharide and the alcohol soluble extract.The results showed that D.catenatum was stressed by high temperature,low temperature,low humidity,direct sunlight,large temperature difference between day and night,which was beneficial to the accumulation of polysaccharides and secondary metabolites.To sum up,D.catenatum C13 can grow normally in three environments,which has strong ecological adaptability.The environment can significantly affect the phenology,morphological characteristics,microstructure and metabolic components of D.catenatum C13. |
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