[Floral biology and breeding system of Merostachys riedeliana (Poaceae: Bambusoideae)]
[Floral biology and breeding system of Merostachys riedeliana (Poaceae: Bambusoideae)]
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DOI：
10.1590/s0100-84042001000200011
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发表时间：
2001-01-01
期刊：
影响因子：
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通讯作者：
Ressel, Kaila
中科院分区：
文献类型：
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作者：
Guilherme, Frederico Augusto G.;Ressel, Kaila
Merostachys riedeliana Rupr。是一种长寿命的单果物种，常见于巴西米纳斯吉拉斯州南部热带半落叶森林的下层。对其花生物学和育种系统进行了研究，并与其他竹类进行了比较。由于它的根茎，它以块状出现，并具有显著的营养增殖能力，这种能力在第一次花序出现前几个月就停止了。1998年10月开始开花，1999年5月全部死亡。开花高峰发生在一年中炎热多雨的月份（12月和1月）。每个花序平均产生29个小穗，这些小穗具有雌雄同体的小花，具有三个雄蕊和两个在花期暴露的羽状柱头。丰富的花粉很容易被风或访客释放出来。蜜蜂和Trigona spinipes （F.）是最常见的访花者，表现为花粉窃贼。这些蜜蜂偶尔会通过花药产生的振动来传播花粉。花期雨水过多和森林下层缺乏风限制了防风的有效性。然而，花、落叶和密集丛的一些形态特征倾向于风传粉。自不亲和指数为0.99，表明竹属自亲和竹。因此，植物无性系的自交不亲和性不利于果实的形成，而自交不亲和性可以导致种子的高产。因此，由于有效的营养生长和30-32年的开花周期间隔，在森林碎片中可能出现的无性系可能解释了在小穗生产和自亲和性果实形成方面的高投资。
Merostachys riedeliana Rupr. is a long-lived monocarp species common in the understorey of tropical semideciduous forest fragments in the south of Minas Gerais, Brazil. Its floral biology and breeding system were studied and compared with others bamboos. Due to its rhizome, it occurs in clumps and has a remarkable capacity for vegetative multiplication, which ceases a few months before the emergence of the first inflorescences. The beginning of the flowering and the death of the entire population occurred respectively on October 1998 and May 1999. The peak of the blooming episode took place during the hot and rainy months of the year (December and January). Each inflorescence produces in average 29 spikelets, which have hermaphrodite florets with three stamens and two plumose stigmas that are exposed during the anthesis. The abundant pollen is easily released by the wind or visitors. Apis mellifera L. and Trigona spinipes (F.) were the commonest visitors and behave as pollen thieves. These bees occasionally act as devices for dispersion of pollen, through vibration produced in the anthers. The excess of rain during flowering and the lack of wind in the understorey of the forest constrain the effectiveness of the anemophily. However, several morphological characters of the flowers, leaf fall and dense clumps tend to expect for wind pollination. Also, the auto-incompatibility index (0.99) showed that M. riedeliana is an autocompatible bamboo. So the auto-incompatibility does not favour the formation of fruits in vegetal clones, and the autocompatibility could result in the high production of seeds. Therefore the possible occurrence of clones of M. riedeliana in the forest fragments, due to the effective vegetative growth and the 30-32 years cyclic flowering intervals, might explain the high investment on spikelets production and autocompatible fruits formation.