Michigan State University-Atomic Energy Commission Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA.
Planta. 1971 Mar;101(1):26-42. doi: 10.1007/BF00387688.
A study of photodormant lettuce embryos germinating in water showed that red light induces an increased rate of water uptake. Determinations of the water potential, carried out by a modified gravimetric technique which eliminates errors introduced by solute penetration into cellular osmotic space, showed that the water potential of embryos germinating in water after dark and red light treatment was equivalent and equal to the osmotic potential of a 0.0 to 0.1 molal mannitol solution. Osmotic potentials of the embryos were determined using two new methods. One of the methods utilizes penetration of deuterated water; the other, penetration of a labeled osmoticum into the tissue. For both light- and dark-treated embryos in water, the osmotic potential was equivalent to that of a 0.34 to 0.41 molal mannitol solution. Lettuce embryos thus require that turgor pressure reach a threshold considerably above zero before growth can occur.
对在水中萌发的光休眠生菜胚的研究表明，红光诱导水的摄取率增加。通过一种改良的重量法测定水势，该方法消除了溶质渗透到细胞渗透空间引起的误差，表明黑暗和红光处理后在水中萌发的胚的水势与 0.0 至 0.1 molal 甘露醇溶液的渗透压相等。使用两种新方法测定了胚的渗透压。一种方法利用氘化水的渗透；另一种方法是将标记的渗透剂渗透到组织中。对于在水中的光和暗处理的胚，渗透压与 0.34 至 0.41 molal 甘露醇溶液的渗透压相等。因此，生菜胚需要在膨压达到零以上的阈值后才能生长。
