中国蓼属萹蓄组植物果实形态的研究

A study on fruit morphology of Polygonum sect. Polygonum (Polygonaceae) from China

应用解剖镜和电子扫描显微镜对中国产蓼属萹蓄组Polygonum sect.Polygonum 16种1变种及1变型植物的果实形态进行了研究。发现该组5种一年生植物的果实具有两型性,即有长、短两种果实类型。短果类型为卵形,具三棱,包于宿存花被内或与花被近等长,呈黑褐色。在解剖镜下观察到其表面具小点、无光泽,而在电子扫描显微镜下观察到其表面具有散乱分布或排列成行的瘤状颗粒;长果类型为狭卵形,具三棱,长于宿存花被,黄褐色或淡黄绿色,在解剖镜下观察到其表面平滑、有光泽,而在电子扫描显微镜下观察到其表面上部具有散乱分布的瘤状颗粒,中、下部则具不规则洼点、星花状褶皱或浅波纹状。果实具两型性的植物有萹蓄P.aviculare、乌鲁木齐萹蓄P.urumqiense、展枝萹蓄P.patulum、直立萹蓄P.avicularef.erectum和尖果萹蓄P.rigidum。果实微形态可分为两种类型:1.果实表面无瘤状颗粒或疣状突起、有光泽,此类型又可以分为2种亚类型:(1)果实表面平滑、浅波纹状,如岩萹蓄P.cognatum、松叶萹蓄P.acerosum和帚萹蓄P.argyrocoleum;(2)果实表面具浅洼点或洼点,如铁马鞭P.plebeium和针叶萹蓄P.polycnemoides。2.果实表面有瘤状颗粒或疣状突起,无或具微光泽,此类型又可分为4种亚类型:(1)果实表面具疣状突起,如圆叶萹蓄P.intramongolicum.;(2)果实表面具散乱分布的瘤状颗粒,如普通萹蓄P.humifusum和展枝萹蓄的短果;(3)果实表面具有纵行排列的瘤状颗粒,如萹蓄和乌鲁木齐萹蓄的短果;(4)果实表面上部具散乱分布的瘤状颗粒,中、下部具不规则洼点、星花状褶皱或浅波纹状,如萹蓄、展枝萹蓄、直立萹蓄和尖果萹蓄的长果。因此果实两型性和果实微形态特征对蓼属萹蓄组种、变种的鉴定具有较大的分类学价值。基于果实微形态特征以及其他形态特征,确定了新种晖春萹蓄Polygonum huichunense F.Z.Li,Y.T.Hou&C.Y.Qu,同时恢复褐鞘萹蓄Polygonum aviculareL.var.fusco-ochreatum(Kom.)A.J.Li为原种,即Polygonum fusco-ochreatum Kom.。

The morphology of fruits in 16 species, one variety and one form of Polygonum sect. Polygonum from China was studied under stereoscope and scanning electron microscope （SEM）. Fruits were observed heterocarpic in five species of the annuals of Polygonum sect. Polygonum, viz., shorter fruits （shorter or sub-equal to persistent perianths） vs. longer fruits （obviously longer than persistent perianths）. Based on morphology of achene surface, fruits of Polygonum sect. Polygonum can be divided into two types： （1） achenes smooth and shiny, but not tuberculate or verrucate; （2） achenes scabrous, but not or slightly shiny, tuberculate or verrucate. The first type includes two subtypes： （1） achenes shallowly waved, e.g., P. cognatum, P. argyrocoleum and P. acerosum; （2） achenes with irregular hollows or stellate plications, e.g., B plebeium, P. polycnemoides and P. shiheziense. The second type includes four subtypes： （1） achenes irregularly verrucate, e.g., P. intramongolicum; （2） achenes with scattered tubercules, e.g., P. humifusum and the shorter fruits ofP. patulum; （3） achenes with tubercules standing in a queue, e.g., P. aviculare, P. tachengense and shorter fruits of P. urumqiense; （4） achenes with tubercules scattered in upper part and hollows or stellate plications in lower part, e.g., the longer fruits of P. aviculare, P. aviculare f. erectum, P. patulum and P. rigidum. The heterocarpy and micro-morphological characteristics of fruits are valuable to identify species and varieties in Section Polygonum. In this study, the systematic position ofPolygonum aviculare L. var. fusco-ochreatum （Kom.） A. J. Li was determined and restated as Polygonum fusco-ochreatum Kom. and a new species, Polygonum huichunense F. Z. Li, ＆. T. Hou ＆ C. Y. Qu, was described.