Aerenchyma and barrier to radial oxygen loss are formed in roots of Taro (Colocasia esculenta) propagules under flooded conditions
Aerenchyma and barrier to radial oxygen loss are formed in roots of Taro (Colocasia esculenta) propagules under flooded conditions
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DOI：
10.1007/s10265-019-01150-6
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发表时间：
2019-11-13
影响因子：
2.8
通讯作者：
Miyasaka, Susan C.
中科院分区：
文献类型：
--
作者：
Abiko, Tomomi;Miyasaka, Susan C.
芋(Colocasia esculenta(L.)肖特)主要是因为其淀粉状的地下茎(即球茎)而种植。它既适用于旱地条件，也适用于湿地(即洪水)条件。虽然芋暴露在淹水土壤中的低氧环境中，但它对低氧的适应机制尚不清楚。为了阐明芋对湿地条件的地下适应性，我们在低氧条件下(n=3)对5个芋品种/地方种进行了为期8天的水培栽培，并分析了：(1)营养繁殖产生的最长根的长度；(2)通风组织(即含有气隙的组织)；(3)根尖两侧的氧化条件。野生芋和中国品种彬龙的根长显著长于夏威夷品种/地方品种毛伊勒华、皮亚阿里和伊勒奈亚(P<；0.05)。在Aweu和Bun-Long的根中一致地观察到通风组织的形成，即在低氧条件下允许氧气有效运输的空气空间，但只有在夏威夷品种/地方品种的根中偶尔观察到。在所有品种/地方品种中，仅在根尖附近检测到径向氧气渗漏的模式。总而言之，在湿地条件下，芋似乎形成了通风组织，并氧化了根尖周围的根际。
Taro (Colocasia esculenta (L.) Schott) is cultivated primarily for its starchy underground stem (i.e., corm). It is adapted to both upland and wetland (i.e., flooded) conditions. Although taro is exposed to hypoxia that occurs in waterlogged soil, the mechanisms of its adaptation to hypoxia were unknown. To clarify the below-ground adaptation of taro to wetland conditions, we grew five taro cultivars/landraces hydroponically for 8 days under hypoxic conditions (n = 3) and analyzed: (1) the length of the longest root that emerged from the vegetative propagule; (2) aerenchyma (i.e., tissues containing air spaces); and (3) oxidation conditions around sides of root tips. Wild taro Aweu and the Chinese cultivar Bun-long had significantly longer roots than the Hawaiian cultivars/landraces Maui Lehua, Pi'i'ali'i, and Ele'ele Naioea (P < 0.05). Formation of aerenchyma, or air spaces that allow effective transportation of oxygen under hypoxic conditions, was observed consistently in roots of Aweu and Bun-long, but only occasionally in those of Hawaiian cultivars/landraces. In all cultivars/landraces, a pattern of radial oxygen leakage was detected only near root tips. In summary, taro appears to form aerenchyma and oxidize the rhizosphere around root tips under wetland conditions.