【作者】 毛灵芝；

【导师】 吕洪飞；

【作者基本信息】 浙江师范大学 ， 植物学， 2008， 硕士

【摘要】 铁皮石斛（Dendrobium candidum Wall.ex Lindl.）是兰科石斛属多年生附生草本,为传统名贵中药。其主要药用成分包括石斛碱和多糖。石斛碱的主要药理作用表现在抗肿瘤,降低心率、血压,促进胃液分泌,帮助消化等作用;多糖的药理作用主要表现在免疫增强作用等方面。近年来,由于铁皮石斛的功效导致其采挖量越来越大,目前,铁皮石斛野生资源已濒临枯竭。国内对石斛类植物光合特性及光合作用与环境条件的关系研究不多,而有关铁皮石斛不同季节不同环境下,铁皮石斛的光合特及其主要药用成分的含量变化鲜有报道,而这些对铁皮石斛的产量和质量影响最大,是制约铁皮石斛生长和成活的关键因子。为此,本研究先对铁皮石斛的三个品种:宽叶石斛、窄叶石斛、青梗石斛进行最佳品种的筛选。然后通过在不同季节对最佳石斛品种进行四个不同的遮阴条件（遮阴强度:A＞B＞C＞D）处理,铁皮石斛的光合特性的研究及其主要药用成分多糖和生物碱等相关生理生化指标的测定,来确定最佳的遮阴条件,对实现铁皮石斛可持续开发利用、提高其产量和质量有很高的理论价值和实践价值,对铁皮石斛的生产有很好的指导作用。主要研究结果如下:1、在生物量上,宽叶石斛有比较明显的优势;从各色素指标上来看,在宽叶石斛中,2年叶在各色素含量指标上均高出1年叶约一倍,青梗石斛中,2年叶与1年叶在色素含量上区别不大,窄叶石斛在各色素含量上,2年生叶比1年生叶高出约30%。纵向比较,1年生叶片Chl a,Chl b,Carotenoid,Chl a+b含量均以青梗石斛最高,2年生叶片Chl a,Carotenoid,Chl a+b含量以宽叶石斛最高;从光合上来看,最大净光合速率以宽叶石斛最高,光合时间以宽叶最长,植物呈高光合效率的时间以宽叶最长。2、对铁皮石斛三个品种茎和叶多糖含量的测定结果表明,各品种2年生茎的多糖含量均为最高,其中宽叶＞窄叶＞青梗;铁皮石斛的生物碱含量表现为2年生叶片含量最高,其中青梗＞宽叶＞窄叶。3、根据结果分析各遮阴条件下,春季到夏季是植物生长的高峰期,到秋季基本不再生长。长势上看,春季B、C、D遮阴下长势较好;夏季A、B遮阴下长势较好,秋季以B、C、D遮阴下有生长迹象。春季Pn最大值出现在B遮阴条件下为2.81μmol m^-2s^-1,且高净光合速率持续时间最长。夏季,Pn最大值出现在B遮阴条件下,且高净光合速率持续时间最长;秋季不同遮阴下,D遮阴下的光合时间最长,C遮阴下的净光合速率与光合时间的乘积最高,其次是D;冬季石斛从光合时间上来看D的光合时间最长,其次是C、B、A。从净光合速率与光合时间的乘积上来看,以D的最高,其次是C。4、各遮阴下以2年生茎多糖含量最高,2年生茎以B遮阴下的石斛多糖含量最高,到秋季的时候,各遮阴下多糖均含量均达到最大值,此时,多糖含量最高的是B遮阴下的石斛为31.77%,其次是D遮阴下为25.34%,A遮阴下22.78%,C遮阴下22.52%。叶片在总体多糖含量上明显低于茎,1年生叶片在春夏秋三个季节的时候以D遮阴下石斛叶片多糖含量最高。各个季节各遮阴下的石斛1年生叶片均以秋季为高。2年生叶片在多糖含量上低于1年生叶片。5、2年生叶片生物碱含量高于1年生叶片,叶片的生物碱含以秋季最高,秋季以B、C遮阴下的叶片生物碱含量为高。到秋季的时候,四个遮阴棚内石斛的生物碱含量均达到了该年的最高值,A为0.039%,B为0.044%,C为0.045%,D为0.035%。石斛茎中生物碱含量跟叶片相比,低了很多。各遮阴棚内1年生茎一年四季变化不是很明显,秋季稍微比其它季节高点。四个遮阴棚的石斛1年生茎在春、夏、秋三季时以B遮阴下的最高。2年生石斛茎比1年生茎生物碱含量高。在秋季时各遮阴下石斛2年茎含量均达到最大值,其中A遮阴0.012%,B遮阴0.021%,C遮阴下0.021%,D遮阴下0.018%。3年生茎的含量跟1年生茎接近,比2年生茎低,各遮阴下的生物碱含量在季节间的变化不是很明显。各季节均以B遮阴下的茎含量较高。综上所述,在铁皮石斛的栽培中,应增加对宽叶品种的引种栽培;适宜铁皮石斛生长的遮光率是:春季B-C,夏季A-C,秋季B-C,冬季C-D。铁皮石斛多糖含量,在各个遮阴处理中以秋季最高,含量可达31.77%;生物碱含量也以秋季最高,可达0.045%,故采收季节以秋季为宜。结合田间实际,考虑到大面积种植,更换遮阴网有一定困难,而C遮光率的遮阴网对铁皮石斛产量和质量,都取得较好结果,所以大面积推广C遮阴网。更多还原

【Abstract】 Dendrobium candidum is an epiphytic herb native mainly to regions in South China.As a traditional Chinese medicine,whose main officinal components are polysaccharide and alkaloid,it is used for curing cataract, throat inflammation,peripheral obstruction and chronic superficial gastritis according to the Pharmacopoeia of the People’s Republic of China.Polysaccharides have been found to possess immmuno-stimulating, anti-tumor and anti-mutagenic activities.But because of the excessive collection for growing medicinal demands and deterioration of their natural habitats,the wild resources are approached in exhausted or endanger.Hitherto,few researches were studied on the photosynthetic characters and the relationship between photosynthesis and environment conditions about D.candidum.The quality and quantity of plants are usually determined by the dry matter production,which is correlated with photosynthesis.And the photosynthetic rate depends strongly on environmental conditions,such as irradiance,temperature and nutrient supply.Thus,it is very significant for people to find a new,fast way to determine the best mode of cultivation.In this study,a best variety D. candidum of was firstly selected（Kuanye,Zhaiye,Qingeeng）,and then cultivated under four different shades（shade intensity:A＞B＞C＞D）.The photosynthetic characters,chlorophyll contents,biomass,polysaccharide and alkaloid contents were determined in order to estimated the best-cultivated environment.The main findings are as follows:1.Kuanye has more obvious advantages according to the biomass. The pigment contents in Kuanye of 2-year-old were 2 times more than those 1-year-old plants.There was no statistic difference in Qingeng’s 1-year and 2-year leaves.Pigment contents in the 2-year leaves of Zhaiye were about 30%higher than 1-year leaves.Longitudinal comparison,the Chl a,Chl b,Carotenoid,Chl a+b contents of 1-year leaves were the highest in Qingeng,while those of 2-year leaves were the highest in Kuanye.Besides,the highest net photosynthetic rate,longest photosynthesis time,and longest high-photosynthesis-last time were found in Kuanye.2.According to the results,all of the 2-year-old stems had the highest content of polysaccharides,and Kuanye＞Zhaiye＞Qingeng;all of the 2-year-old leaves had the highest content of alkaloid,and Qingeng＞Kuanye＞Zhaiye.3.In accordance with the results of the shade conditions,spring to summer is the peak period for plant growth,and autumn is no longer essential to the growth.Plants grow well under the shade of B,C,and D in spring,while under A,B in summer,B,C,D in autumn.Maximum Pn that was about 2.81μmol m^-2s^-1in spring were found under B shade,under which high net photosynthetic rate lasted the longest.In summer, maximum Pn and longest high net photosynthetic rate lasted were found under B shade.In autumn,photosynthesis time lasted longest under D shade,while the product of net photosynthetic rate and photosynthetic time were highest in C,followed by D.In winter,the longest photosynthesis time and highest product of net photosynthetic rate and photosynthetic time were found under D shade,followed by the C.4.Polysaccharide contents in all the shade were highest in 2-year stems in autumn.Polysaccharide content of 2-year stems under B,which was about 31.77%shade were highest,followed by D 25.34%,A 22.78%, C 22.52%.The content in leaves in the overall was significantly lower than stems and 1-year leaves from spring to autumn under D shade had highest polysaccharide content.Polysaccharide content in 2-year leaves was less than 1-year leaves.5.2-year-old leave had a higher alkaloid content than 1-year-old leaves,and alkaloids in leave were highest in the autumn,when under B, C shade had higher alkaloid content.In the autumn,the alkaloid in leave under four shade all reach their maximum value,which was 0.039%for A, 0.044%for B,0.045%for C,and 0.035%for D.Compared with the leaves,alkaloids in stem were much lower.The yearly changes of alkaloid in 1-year stems were not very significant.From spring to autumn, the highest alkaloid contents in 1-year stems were found under B shade. 2-year stem had much higher alkaloid contents than 1-year stems,and reach their maximum in autumn,when alkaloid of 2-year stems under A shade was 0.012%,B 0.021%,C 0.021%,D 0.018%.The contents in 3-year stems that were similar with those in 1-year stems were highest under B shade in same season,and the changes were not obvious between seasons.To sum up,in the cultivation of D.candidum,it is better to choose Kuanye as a widely-plant variety.In field cultivation,the suitable shade condition for D.candidum was B,C shade in spring,A-C in summer,B, C in autumn,C,D in winter.Polysaccharide contents were highest in autumn in various shelters,which could be up to 31.77%;alkaloid contents were highest in autumn,which could be up to 0.045%.So autumn is the suitable harvest season.But considering the large-scale cultivation,it is difficult to replace shade net,and the yield and quality of D.candidum under C shade were proved to be good results,so in field cultivation,C shade was suggested.更多还原