Parsons Richard, Sprent Janet I, Raven John A
Biological Sciences, University of Dundee, Dundee DD1 4HN, UK.
New Phytol. 1993 Dec;125(4):749-755. doi: 10.1111/j.1469-8137.1993.tb03924.x.
The growth and nitrogenase activity of stem nodules of Sesbania rostrata Brem were strongly influenced by the humidity surrounding the nodule. Nodules developed under high humidity showed the fastest rates of growth and the highest specific nitrogenase activity (determined by acetylene reduction). Development of stem nodules in both the light and dark was similar and showed a similar lowering of growth and activity with decreasing humidity. Stem nodules developed in the dark were pale and unlike the dark green nodules that developed in the light, they did not have chloroplasts in the nodule cortex. Adventitious root development required darkness and relative humidities approaching 100%. In stem nodules that were grown at high humidity and subsequently exposed to lower humidities, there was only a small loss of nitrogenase activity, and high rates of acetylene reduction were maintained for 6 d after treatments were begun. The area of nodule attachment to the stem or root was measured in nodules of many sizes and found to be consistently greater in stem nodules. This may have implications for the comparative water balance of nodules on these two organs.
喙荚田菁茎瘤的生长和固氮酶活性受瘤周围湿度的强烈影响。在高湿度条件下形成的瘤生长速度最快，比固氮酶活性最高（通过乙炔还原法测定）。茎瘤在光照和黑暗条件下的发育相似，并且随着湿度降低，生长和活性呈现相似的下降趋势。在黑暗中形成的茎瘤颜色苍白，与在光照下形成的深绿色瘤不同，其瘤皮层中没有叶绿体。不定根的发育需要黑暗和接近100%的相对湿度。在高湿度条件下生长并随后暴露于较低湿度的茎瘤中，固氮酶活性仅略有损失，并且在处理开始后6天内保持较高的乙炔还原率。在许多大小的瘤中测量了瘤与茎或根的附着面积，发现茎瘤中的附着面积始终更大。这可能对这两个器官上瘤的比较水分平衡有影响。
