Plant growth and development, and auxin polar transport in space: Effects of auxin polar transport inhibitors on growth and development of etiolated pea epicotyls grown under simulated microgravity conditions on a three-dimensional clinostat
Osaka Prefecture University Graduate School of Science
Osaka Prefecture University Graduate School of Science
Osaka Prefecture University Faculty of Liberal Arts and Sciences
出版者
宇宙航空研究開発機構宇宙科学研究本部
出版者（英）
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA/ISAS)
雑誌名
宇宙利用シンポジウム 第24回 平成19年度
雑誌名(英)
Space Utilization Research: Proceedings of the Twenty-fourth Space Utilization Symposium
ページ
397 - 400
発行年
2008-03
抄録（英）
Both true microgravity conditions in space (STS-95 space experiment) and simulated ones using a three-dimensional (3D) clinostat induced automorphosis together with significant inhibition of auxin polar transport in epicotyls of etiolated pea (Pisum sativum L. cv. Alaska) seedlings. Increased expression of the auxin-inducible gene PsIAA4/5 was observed in the elongated side of epicotyls in the early growth stages of etiolated pea seedlings grown in a horizontal or an inclined position under 1 g conditions. Under simulated microgravity conditions on a 3D clinostat, accumulation of PsIAA4/5 mRNA (messenger Ribonucleic Acid) was found throughout epicotyls showing automorphosis. Polar auxin transport in the proximal side of epicotyls changed when the seedlings were grown in a horizontal or an inclined position under 1 g conditions, but that under clinorotation did not, regardless of the direction of seed setting. Accumulation of PsPIN1 and PsPIN2 mRNAs in epicotyls was affected by gravistimulation, but not by clinorotation. Under 1 g conditions, auxin-transport inhibitors made epicotyls of seedlings grown in a horizontal or inclined position grow toward the proximal direction to cotyledons. These inhibitors led to epicotyl bending toward the cotyledons in seedlings grown in an inclined position under clinorotation. Polar auxin transport, as well as growth direction, of epicotyls of the agravitropic pea mutant, ageotropum, did not respond to various gravistimulation. These results strongly suggest that alteration of polar auxin transport in the proximal side of epicotyls regulates the graviresponse of pea epicotyls. It is also possible that one-way lateral auxin distribution in epicotyls in the early growth stage of etiolated pea seedlings is responsible for graviresponse of the seedlings.
宇宙環境下における植物の成長、発達とオーキシン極性移動:特に擬似微小重力環境下で生育させた黄化エンドウ芽生え上胚軸の成長、発達に対するオーキシン極性移動阻害剤の影響
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