Effect of phytosiderophores on ⁵⁹Fe absorption and translocation in arsenic-induced chlorosis in rice and barley seedlings

Abstract

In the greenhouse, rice (Oryza sativa L. cv. Akitakomachi) were grown at pH 5.5, treated with 26.8 μM As (arsenite; NaAsO₂) for 14 days. We found that As-induced whitish chlorosis in the fully developed young leaves. Control and As-treated seedlings were fed with 10 μM ⁵⁹Fe in the absence or in the presence of 10 μM PS (phytosiderophores, mugineic acid) for 4 h in the phytotron to observe the efficiency of PS on ⁵⁹Fe absorption and translocation in plants. Absorption and translocation of ⁵⁹Fe increased in control plants fed with PS as compared with those without being fed with PS, indicating that PS effectively elevated ⁵⁹Fe absorption and translocation. In As-treated plants, PS enhanced ⁵⁹Fe absorption by roots but did not enhance ⁵⁹Fe translocation from roots to shoots. In addition, ⁵⁹Fe absorption was lower in As-treated plants as compared to control plants in the absence or presence of PS. In the phytotron, a similar experiment with barley (Hordeum vulgare L. cv. Minorimugi) was conducted. Barley were grown at pH 6.5 treated with 33.5 μM As for 14 days, showing chlorosis, were fed with ⁵⁹Fe in the absence or presence of PS. In control plants, PS enhanced ⁵⁹Fe absorption and translocation similarly to rice. In As-treated barley, PS enhanced ⁵⁹Fe absorption in roots and PS activity enhanced ⁵⁹Fe translocation from roots to shoots. Our results suggested that As repressed or inhibited the system for PS-Fe³⁺ absorption in gramineae under severe As-stress condition, resulting in appearance of Fe chlorosis.

Keywords:

• Barley
• chlorosis
• iron
• problem
• rice
• translocation

Additional information

Funding

The author wish to express his appreciation to the Ministry of Education, Science, Culture and Sports, Government of Japan, for financial support.