榧树雄株若干性状变异初探

通过调查统计野生榧树Torreya grandis雄株的叶长、叶宽及叶片厚度，球花大小、花粉质量及开花时间等的差异变化．结合花粉粒的扫描电镜观察和香榧Torreyagrandis‘Merrillii’授粉试验，探讨榧树雄株相关性状的变异。结果表明：①雄株叶片要比雌株叶片长，叶片长度均值为2．12cm（变幅1．53～3．20cm），叶片宽度均值为0．32cm（变幅O．28～0．39ClTI），叶厚均值为0．23mm（变幅0．17～0．32mm）；雄球花纵径均值为0．79cm（变幅0．49～1．32cm），横径均值为0．42cm（变幅0．32～0．54cm），雄球花质量均值为1．19g（变幅0．33～2．66g），花粉质量均值为0．170g（0．151～0．548g）。叶片及雄球花的各指标均有较大的变异系数，其中花粉质量的变异系数最大，达55．29％；叶片宽度的变异系数最小．也有8．83％：②雄株开始开花时间主要集中在4月16-18日，不同单株的雄花始花时间存在约1周的差异．营造香榧林时可以按需选择配置，特别应该适＇-3配置晚花类型的雄株；③花粉近球型，直径为22～26¨m；不同地区、同一地区不同单株的花粉在外观上无明显差异；④不同来源的花粉显著影响香榧幼果坐果率，表明榧树雄株具有开展选优的潜力。图2表4参27

Trait variations of male Torreya grandis trees

Abstract： Variation in traits associated with male trees of Torreya graadis were studied using a survey oi leaI length, width, and thickness; size of staminate strobilus; pollen weight; and flowering time. A scanning electron microscope （SEM） was used to observe pollen grains and a pollination test with pollen from different 3 locations and 2 individual male trees of the same location was conducted in T. grandis ＇ Merrillii＇ that is the only female cultivar of T. grandis. Results showed that for male trees on the average, leaf length was 2.12 cm （ranging from 1.53 to 3.20 cm）, width was 0.32 cm （0.28-0.39 cm）, and thickness was 0.23 mm （0.17-0.32 mm） with the length longer than that of leaves from female trees （1.1-2.5 cm） ; for staminate strobilus, length was 0.79 cm （ranging from 0.49-1.32 cm）, width was 0.42 cm （0.32-0.54 cm）, and weight was 1.19 g （0.33-2.66 g）; and pollen weight was 0.170 g （ranging from 0.151-0.548 g）. For leaf and staminate strobilus characteristics, CVs （coefficients of variation） varied from 55.3% for pollen weight to 8.8% for leaf width. Male trees mainly started flowering from the 16th to the 18th of April with a 1-week difference between one another in flowering time. Also, pollen was ball shaped with a diameter of 22-26 lxm. No differences were found in pollen morphology among different origins or individuals located in the same area. Finally, pollen of different origins had a strong effect （P=0.016） on the young fruit-setting percentage of T. grandis ＇Merrillii＇.Thus, differences in flowering time, especially selecting those late in flowering, could be used to select male trees when establishing a T. grandis ＇Men＇illii＇ plantation, and the fruit-set indicated a potential for selection of T. grandis male, elite individuals. Ch, 2 fig. 4 tab. 27 ref. ]