Regulation of the germination of Aleppo pine (Pinus halepensis) by nitrate, ammonium, and gibberellin, and its role in post-fire forest regeneration
Regulation of the germination of Aleppo pine (Pinus halepensis) by nitrate, ammonium, and gibberellin, and its role in post-fire forest regeneration
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DOI：
10.1034/j.1399-3054.2000.108004390.x
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发表时间：
2000-04-01
影响因子：
6.4
通讯作者：
Ne'eman, G
中科院分区：
文献类型：
--
作者：
Henig-Sever, N;Eshel, A;Ne'eman, G
阿勒颇松（Pinus halepensis Mill,）在野火后仅通过发芽再生。这种火后萌发受温度、光照和灰床化学特性的控制，灰造成的极高pH值抑制了阿勒颇松以及许多其他物种的萌发，在这里我们报道了中性pH下的灰提取物刺激P， halepensis萌发。在控制条件下，研究了灰分提取物、硝酸盐、铵（灰分中浓度）和GA(3)对草木种子萌发及萌发初期脂肪酶活性的影响。次优浓度的硝酸盐和氨刺激种子萌发和脂肪酶活性。提出硝酸盐增加种子对GA(3)的敏感性，而铵直接影响脂肪酶活性，灰的高pH值抑制萌发与灰中存在的硝酸盐和铵刺激萌发之间的平衡决定了灰对阿勒颇松火后萌发的整体影响。松苗在林间呈高密度分布，但由于灰分的影响，在被烧松冠层投影下的稀疏林分中出现，这些幼苗受益于弱的种间和种内竞争以及改善的矿物质营养，有很好的机会长成大树，形成更新林；因此，硝态氮和铵态氮对P、halepensis萌发的促进作用和高pH对萌发的抑制作用可以认为是对火后再生的生态生理适应。
Aleppo pine (Pinus halepensis Mill,) regenerates after wildfires only by germination. This post-fire germination is controlled by temperature, light and the chemical characteristics of the ash-bed, The extremely high pH caused by the ash inhibits germination of Aleppo pine as well as of many other species, Here we report that ash extracts at neutral pH stimulate P, halepensis germination. The effects of ash extracts, nitrate, ammonium (in concentrations present in the ash) and GA(3) on the germination of P, halepensis seeds and on lipase activity at early germination were studied under controlled conditions. Sub-optimal concentrations of nitrate-and ammonium-stimulated germination and the activity of lipase in the seeds. It is proposed that nitrate increases seed sensitivity to GA(3) while ammonium directly affects lipase activity, The balance between the inhibition of germination by the high pH of ash and its stimulation by the nitrate and ammonium present in the ash determines the overall effect of the ash on post-fire germination of Aleppo pine. The pine seedlings appear in high density among the trees but because of the effects of the ash they appear in sparse stands under the projection of the burned pine canopies, These seedlings benefit from weak inter- and intra-specific competition as well as improved mineral nutrition and have good chances to grow into large trees that will form the regenerating forest; therefore, the enhancement of P, halepensis germination by nitrate and ammonium and its inhibition by high pH can be considered as ecophysiological adaptations to post-fire regeneration.