【摘要】 以天目山自然保护区人工栽培的濒危树种羊角槭(Acer yangjuechi Fang et P. L. Chiu)为研究对象,于花期观察了花部形态特征、单株与群体水平开花动态,分析开花与结实的关系,结果表明:1.羊角槭花杂性、顶生花序着生有雄花和两性花,两性花多位于花轴顶端,雄花位于侧生轴顶端或下部,花序雄花与两性花数量比为三角槭的2. 6倍,羊角槭枝条两性花偏少; 2.观察到两种形态雄花,Ⅰ型雄花子房微型、柱头极度短缩呈黑点状、花盘较平,Ⅱ型雄花子房退化成一团白色绒毛,2裂柱头隐现,花盘较厚、辐射状凹裂;两性花子房成扁球状突出,柱头显著伸出,花丝长度短于雄花; 3.单株两性花早于雄花开放,两性花集中于3日以内开放,呈集中开放模式,而对应此时同株上只有极个别雄花(7%以下)处于散粉阶段; 4.群体两性花开放时期略早于雄花,二者间存在相对的间隔期。由此对羊角槭开花与种胚发育影响因素进行了探讨。更多还原

【Abstract】 To reveal the reproduction mechanism of low embryo development rate,the floral morphology and flowering process of Acer yangjuechi Fang et P. L. Chiu, the extremely endangered plants in Chinawas determined by testing trees cultivated in National Nature Reserve of Tianmu Mountain,Zhejiang Province. The results show that: (1) Bisexual flowers and maleflowers are inserted on a same apical inflorescence,and the bisexual flowers are always on the top of rachis while maleflowers on lateral rachis top or bottom. The quantity ratio of maleflowers to bisexual flowers is 6. 89 of 2. 6 times exceeding to A. buergerianum,which indicates less bisexual flowers of A. yangjuechi than A. buergerianum. (2) Two type of maleflowers were observed. Type Ⅰmaleflowers have tiny ovary,the stigma shortened extremely to a black spot and with flat flower disc while TypeⅡmaleflowers have biforked stigma outstanding upon ovary degenerated into white fluff and with thick and radial sunken flower disc. Bisexual flowers possess of outstanding oblate spheroid and shorter filament compared with maleflowers. (3) The flowering process of individual tree is of bisexual flowers flowering within 3 days previous to maleflowers while only under seven percent of maleflowers were on pollination stage at the same time. (4) For population flowering process,the flowering stage between bisexual flowers and maleflowers present an obvious interval and bisexual flowers flowering intensively previous to maleflowers. Therefore,the main cause of the high embryo abortion,which leads to endangered situation of A. yangjuechi,was discussed.更多还原