Sporeling regeneration and ex situ growth of Isoetes cangae (Isoetaceae): Initial steps towards the conservation of a rare Amazonian quillwort
Sporeling regeneration and ex situ growth of Isoetes cangae (Isoetaceae): Initial steps towards the conservation of a rare Amazonian quillwort
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DOI：
10.1016/j.aquabot.2018.10.001
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发表时间：
2019-01-01
期刊：
影响因子：
1.8
通讯作者：
Siqueira, Jose Oswaldo
中科院分区：
文献类型：
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作者：
Caldeira, Cecilio Frois;Abranches, Cinthia Bandeira;Siqueira, Jose Oswaldo
[医]异甘草是一个几乎世界性的根状石松属，因为它在植物界的独特地位，对解开植物进化至关重要。最近描述的一种受威胁的亚马逊物种是I。cangae，居住在一个贫营养的高地湖泊上的富铁地区面临着重大的环境变化。在这项研究中，我们的目标是优化的繁殖协议，可以帮助在热带地区的Isopropylene物种的保护工作。在野外采集的植物中，我们观察到每个孢子囊平均有126个大孢子或318，000个小孢子。我们从大孢子和小孢子的体外混合培养中获得了较高的孢子比例（63%）。此外，我们在石英砂和蒸馏水上培养它们后，在成年植物周围回收了大量的孢子。大孢子的营养储备保证了孢子在这些环境条件下的长期生长和发育。然而，孢子的生长速率增加时，他们种植在原来的湖泊沉积物或有机基质，与基质之间的差异不显着。温度的升高也增加了孢子的生长速率。结合极低的孢子死亡率，这些结果表明，I。cangae是一种适应性强的物种，能够在具有低营养特性的环境中生长和定殖，并具有一系列基质和温度制度。在这项研究中建立的协议可能是有用的迁地繁殖和大量的孢子的生长，代表的关键步骤，对人口的拯救和保护的热带Isopropyl物种。
Isoetes L. is a nearly cosmopolitan rhizomorphic lycopsid genus fundamental to disentangling plant evolution because of its singular position in the Plantae kingdom. A threatened Amazonian species recently described is I. cangae, inhabiting an oligotrophic upland lake over an iron-rich region facing substantial environmental alterations. In this study, we aim to optimize a reproduction protocol that can assist in the conservation efforts of Isoetes species in tropical areas. We observed an average of 126 megaspores or 318,000 microspores per sporangia in field-collected plants. We obtained an elevated percentage of sporelings (63%) from an in vitro mixed culture of mega- and microspores. In addition, we recovered a large number of sporelings around adult plants after cultivating them over quartzite sand and distilled water. The megaspore nutrient reserve ensured long-standing sporeling growth and development in these environmental conditions. However, the sporeling growth rate increased when they were planted over their original lake sediments or over an organic substrate, with nonsignificant differences between the substrates. An increase in temperature also increased the sporeling growth rate. Together with the very low sporeling mortality, these results suggest that I. cangae is a resilient species able to grow and colonize environments with low trophic characteristics with a range of substrates and temperature regimes. The protocols established in this study could be useful for the ex situ propagation and growth of a large number of sporelings, representing critical steps towards the population rescue and conservation of tropical Isoetes species.