高等植物の生活環と重力環境: 過重力環境が生殖生長に与える影響

摘要

Plant life cycle consists of successive phases of vegetative and reproductive growth. The effects of altered gravity conditions on reproductive growth is poorly understood compared to vegetative growth, although understanding the effects is especially important not only to reveal how plants evolved under gravity on earth but to develop agriculture in space. In the present study, we examined the effects of hypergravity conditions on gene expression during reproductive growth in Arabidopsis. Micro array analysis (44K) was performed to identify genes that are modulated in expression in response to hypergravity treatment in flower buds. Plants were grown for 20-26 days before exposure to hypergravity at 300 x g for 24 h. Total RNA was isolated from the flower buds (stage 1-12 according to Smyth et al. (1990)) after hypergravity treatment. Our results showed that several genes involved in reproductive growth were expressed at less than 0.2-fold levels under hypergravity condition, suggesting that expression of genes involved in flower, embryo, and seed development was suppressed under hypergravity.%植物は動物のように動き回ることができないため、おかれた環境の変化に対してその生活環をいかこうまく順応させるかは、生存のために大きな鍵を握る。植物は、地球上で常にほぼ一定の大きさで存在する重力環境下において生活環を全うできるように進化してきた。従って、重力環境が植物の生活環に与える影響を調べることは、地球上の重力環境が植物の形態形成や代謝過程にどのように関わってきたかという、植物学上の重要な課題の解明のために重要である。