南方红豆杉响应不同传粉式样的结实表现

采用开花前雌株短枝套袋隔离传粉、花期人工授粉、风媒传粉 对照 及其传粉障碍等几种传粉式样 ,比较不同传粉 授粉 方式对南方红豆杉 Taxus chinensis var.mairei 结实的影响 ;在风媒传粉条件下 ,研究了南方红豆杉不同种植行向、树冠不同方位、上下内外不同层面的结实表现 .结果表明 :南方红豆杉存在孤雌生殖现象 ,平均单枝结实率为 2 8.7% ,与风媒传粉相比较 ,存在极显著差异 P<0 .0 1 ;人工授粉能显著提高结实率 P<0 .0 5 2 0 .7% ;2～ 3月份开花期 ,江汉平原盛行东北风 ,在风媒传粉条件下 ,东西向种植的南方红豆杉有更多的授粉机会 ,其结实情况极显著优于南北向种植的 P<0 .0 1 ;东西向种植的南方红豆杉树冠果实的空间分布 ,受传粉条件包括风向、冠层方位及距传粉源的距离、冠层内外上下层次等因素的影响 ,方位间的结实量按东南西北方位依次为 :2 30 .375粒、185 .6 2 5粒、12 8.813粒、10 5 .4 38粒 ,呈递减趋势 ,冠外层结实量普通高于冠内层 ,树冠东向下外层结实量最高 4 16 .75粒 ,北向下内层最低 2 2 .0 0粒 .

Fruit Settings of Taxus chinensis var.mairei in Responding to Different Pollination Types

In the experiment,some pollination ways were arranged adult Taxus chinensis var.mairei trees as follows:covering short branches with female flower buds isolating pollination using plastic bags before flowering,artificial pollination,wind pollination (control) and wind pollination being hindered by leaves and branches,and fruit setting of T.chinensis var.mairei were compared among the pollination ways.In wind pollination experiment,fruit setting was studied with different planting line directions and upper-lower-inside-outside different levels of tree canopies.The results showed that T.chinensis var.mairei presented parthenogenetic propagation,the average fruit setting rate of single branches were 28.7%,significantly different from that in wind pollination (P<0.01).The fruit setting rate of single branches in artificial pollination experiment was significantly higher than that in wind pollination experiment (P<0.05) and increased by 20.7%.From February to March,the flower phase,northeastern wind were dominant Jianghan Plain,thus there were more pollination opportunities for trees planted in east-west planting line direction,therefore,the fruit setting rates of trees were significantly higher than that of trees planted in south-north planting line direction (P<0.01).For the trees in east-west planting line direction,the spatial distribution of fruits in tree canopies were influenced by pollination factors,such as wind direction,canopy positions,and distance from source of pollination.Fruit setting reduced in the order of east (230.375 grains)-south ((185.625 grains))-west (128.813 grains)-north (105.438 grains).The fruit setting of outer tree canopies was more than that of inner tree canopies,the fruit setting was the highest at low parts of outer canopies facing east (416.75 grains),and the fruit setting was the lowest at low parts of inner canopies facing north (22.00 grains).