Comparison of iron availability in leaves of barley and rice
Comparison of iron availability in leaves of barley and rice
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DOI：
10.1111/j.1747-0765.2005.tb00142.x
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发表时间：
2005-12-01
影响因子：
2
通讯作者：
Tadano, T
中科院分区：
文献类型：
--
作者：
Maruyama, T;Higuchi, K;Tadano, T
铁（Fe）是所有真核生物必需的微量元素。在高等植物中，缺铁导致幼叶脉间失绿。然而，在大麦和水稻，这两者都是“战略II”的植物，程度和模式的缺铁症状不同。在本研究中，大麦和水稻植物生长在同一容器中，即，通过“共培养”，以补偿营养液中大米中的麦麦角酸的量。我们研究了铁的差异可用性的分布和再转运在大麦和水稻之间的芽不考虑铁的收购能力，这是由大麦和水稻之间的差异麦红氨酸分泌的影响的差异。虽然在共培养条件下大麦幼叶的铁浓度有所下降，但SPAD值与单作大麦相似。与此相反，虽然有一个增加的Fe浓度的共培养水稻的幼叶，SPAD值下降，在单作水稻的情况下。水稻积累铁在老叶，而在大麦铁有效地分配到幼叶。因此，水稻倒二叶的SPAD值一直保持较高水平。缺铁共培养使大麦倒二叶铁浓度降低，SPAD值降低，倒二叶衰老加快。Fe-59脉冲标记实验表明，在大麦中，铁是更有效地从老叶到幼叶比水稻。结果，在Fe缺乏条件下，分子量低于10，000/水溶性Fe比率的级分中存在的Fe水平在大麦的老叶中高于在水稻的老叶中。根据以上结果，我们认为大麦体内铁的分配和转运特征可能与缺铁有关。
Iron (Fe) is an essential trace element in all eukaryotes. In higher plants, Fe deficiency causes interveinal chlorosis in young leaves. However, in barley and rice, both of which are "Strategy II" plants, the degree and the pattern of Fe-deficiency symptoms differ. In the present study, barley and rice plants were grown in the same container, i.e., by "coculturing," to compensate for the amount of mugineic acids in rice in the nutrient solution. We examined the differential availability of Fe for distribution and retranslocation in shoots between barley and rice without considering the difference in the iron acquisition ability, which is affected by the differential mugineic acid secretion between barley and rice. Although the Fe concentration of young barley leaves had decreased under the coculture conditions, the SPAD value was similar to that in monocultured barley. In contrast, although there was an increase in the Fe concentration of the young leaves of cocultured rice, the SPAD value decreased, as in the case of monocultured rice. Rice accumulated Fe in old leaves, whereas in barley Fe was efficiently distributed to young leaves. Therefore, the SPAD value of the second leaf in rice remained constantly high. The Fe concentration of the second leaf in barley decreased under Fe-deficient coculture conditions, the SPAD value decreased and the senescence of the second leaf become accelerated. Fe-59 pulse-labeling experiments suggested that in barley Fe was more efficiently retranslocated from old leaves to young leaves than that in rice. As a result, the level of Fe present in the fraction with a molecular weight lower than the 10,000/water-soluble Fe ratio was higher in the old leaves of barley than in the old leaves of rice under Fe-deficient conditions. Based on the results obtained, we suggest that the distribution and retranslocation characteristics of internal Fe in barley may be well adapted to Fe deficiency.