高等植物の生活環研究班WGの活動報告

摘要

Many scientists have made much effort to clarify how reproductive growth is affected under microgravity conditions, because growth and development in higher plants are dependent on the influence of gravity. So far, various types of higher plants have been grown in space. In many cases, the process of reproductive growth has been reported to be abnormal under microgravity condition. In these space experiments, however, control experiments were conducted under 1g condition on the ground. In addition to gravity, the environmental conditions such as radiation and magnetic field are quite different between space and Earth. In order to assess the effect of gravity on reproductive growth in higher plants, we have organized a working group, consisting of 28 members from different research fields of plant science. The goal of our working group is to clarify whether or not the seed to seed life cycle of higher plants is normally completed under microgravity condition in space, using plant experiment units embarked in Japanese experiment module (JEM) with a centrifuge to produce 1g condition.%宇宙植物学の分野で、特に我が国で研究されているのが、重力植物学である。陸上植物は約4億年前に水中から陸上に進出した。陸上植物は重力刺激のベクトル情報を巧みに利用して、根を地下に伸ばし、茎を上に伸ばす。この現象は重力屈性と呼ばれ、陸上植物の姿勢制御に重要な役割を果たしている。また、陸上植物は1gの重力に逆らつてその地上部を空間に支えるために、細胞壁を強固にし、支持組織である通導組織を発達させた。