枸橼药用植物果实变异及地理分布研究

Fruit variation and geographical distribution of citron

枸橼Citrus medica的成熟干燥果实既是中药材香橼的重要来源之一,又是食用和观赏种质资源,其植物类型多,遗传变异丰富。为调查枸橼种内果实变异和资源分布情况,该研究采用实地调查方法,研究了11种枸橼类型果实变异情况,基本涵盖我国主要枸橼类型,分别为小果香橼C.medica var.ethrog、枸橙(云南香橼)C.medica var.yunnanensis、木里香阳果C.medica var.muliensis、德宏元橼C.medica×Citrus spp.、福州枸橼C.medica×C.grandis?、麻屋C.medica×C.grandis?、苍源香橼(野香橼)、宾川香橼、甜香橼、大香橼、小香橼(酸香橼)。调研发现枸橼自然群落主要分布在云南西南部和西部、西藏东南部,主产地有云南、四川、广西、重庆、湖北、浙江等地,枸橼在世界上也有广泛种植,包括印度、地中海地区和加勒比海岸国家。实地调查发现枸橼果实总体呈现种内变异大的特点,枸橼类的果实大多为类椭圆形或类球形,皮生绿熟黄,带油胞点,多有贯穿底部到顶部的棱起和乳突,通常越小的枸橼类型囊瓣和汁胞越发达,中心柱紧实,越大的枸橼类型囊瓣和中心柱越空虚,具有心皮群,而心皮群先端分离发育是产生变种的原因之一。在未来品种选育过程中应高度重视这些变异,进一步研究不同枸橼种类品质差异及其机制,根据其药用或食用用途分别进行品种选育,分类管理,为药食同源药材有序、安全、有效生产提供科技支撑。

The ripe dried fruit of citron(Citrus medica)is one of the important sources of Chinese herb Citri Fructus.At the same time,it is also grown for edible and ornamental uses.There are many species and abundant genetic variation.To clarify the intraspecific variation and resource distribution of citron,this study investigated the variation in 11 citron fruits,basically covering the main species in China,including Xiaoguo citron(C.medica var.ethrog),Goucheng(C.medica var.yunnanensis),Muli citron(C.medica var.muliensis),Dehong citron(C.medica×Citrus spp.),Fuzhou citron(C.medica×C.grandis?),Mawu(C.medica×C.grandis?),Cangyuan citron,Binchuan citron,Sweet citron,Big citron,and Small citron.The natural communities of citron were proved to be mainly distributed in the southwestern and western Yunnan and southeastern Tibet of China,with Yunnan,Sichuan,Guangxi,Chongqing,Hubei,and Zhejiang identified as the main production areas.Citron has also been widely grown in India,the Mediterranean region,and the Caribbean coast countries.The field investigation revealed the large-scale intraspecific variation of citron fruits.Most of the fruits are oval-like or sphere-like in shape.The fruits are green when raw and yellow when ripe,with oil cell dots on the skin,stripe-likes running from top to bottom,and bulge at the top.Usually,in the smaller citron fruits,the pulp and juice vesicles are better developed and the central columella is tighter.By contrast,the juice vesicles and central columella in larger fruits became more vacant,with carpels visible,and the apex segregation and development of the carpels is one of the reasons for variation.These variations should be given top priority in the future variety selection and breeding,and the quality differences of different citron species and their mechanisms should be further studied.In particular,variety selection and classification management according to their medicinal or edible purposes will provide scientific and technological supports for the orderly,safe,and effective production of citron products consumed as food and medicine.