| | [這篇文章最後由nirwa在 2010/08/06 03:40pm 第 1 次編輯]
本品種最大的特色在於它的果實是 " 隱果 ( cryptocarpic fruit ) ", 它的果實成熟後並不外露於植體外, 由一薄膜包裹藏於莖中可達數年, 若植體吸水過多才可能釋出種子.
這類有隱果的品種除了 M. hernandezii , 還有 M. theresea , M. saboae , M. longiflora ssp. longiflora , M. longiflora ssp. stampferi , M. luethyi , M. napina , M. solisioides ( 半埋在莖幹中 ) 等 M 屬品種, 除了這些 M. 屬品, 尚包括 Yavia cryptocarpa .
根據一篇研究報告 ( Serotiny and seed germination in three threatened species of Mammillaria (Cactaceae) , Basic and Applied Ecology 2006, Volume 7, Issue 6, 1 November 2006, Pages 533-544 ), M 屬具隱果不同的品種對於種子的成熟以及時間保存上對種子發芽的影響皆有所不同. 以下是該文的總結.
Summary
Individuals of some species of Mammillaria (Cactaceae) store some seeds on the plant over periods exceeding 1 year (serotiny). We examined the phenomenon of serotiny and germination behaviour of three rare and endangered Mammillaria species that occur in central Mexico.
The species with the highest seed retention was Mammillaria solisioides, whose individuals kept on average 24% of their total seed crop throughout their observable lifetime. Individuals of Mammillaria napina and Mammillaria hernandezii did not differ in their degree of seed retention (about 5%). In M. solisioides and M. hernandezii, seed germination declined significantly with seed age, whereas in M. napina germination increased slightly. In all three species, over 70% of retained seeds were still alive after 8 years.
Increasing fractions of dormant seeds were observed with seed age in M. solisioides and M. hernandezii, whereas in M. napina this fraction followed the opposite trend. All three species showed strict light dependence for germination.
Serotiny was positively correlated with the harshness of the environment when species and populations were assumed independent. However, these correlations were not significant at the 5% level when the degree of relatedness of species and populations was taken into account using phylogenetically independent constrasts.
We hypothesise that serotiny in these species represents a mechanism by which they can cope with a harsh, unpredictable environment. To our knowledge, this is the first assessment of serotiny in cacti.
其中有個關鍵字 Serotiny ( 果莢之延遲開裂性 ), 即種子成熟於果莢中並未完全張開，而是將種子保存於果莢內一段時間，果莢於某些狀況才陸續張開將種子釋放.
Wikipedia 上的名詞解釋 : http://en.wikipedia.org/wiki/Serotiny
使果實裂開而釋出種子的可能狀況有 :
1. 母株或附著果莢的枝幹死亡 ( necriscence )
2. 果莢接觸濕氣 ( hygriscence )
3. 果莢受某種程度的日照而溫度上昇 ( soliscence )
4. 不良的空氣狀況 ( xyriscence )
5. 果莢被火烤過或燻過 ( pyriscence )
6. 果莢被火烤過或燻過, 再接著接觸濕氣 ( pyrohydriscence )
這些 M 屬的品種以及 Yavia cryptocarpa 會有這種果莢之延遲開裂, 應與其原生地嚴苛的環境有關, 以適應當地的惡劣氣候或環境.
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2010/06/24 02:56pm 
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