Michigan State University-Atomic Energy Commission, Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA.
Planta. 1971 Mar;101(1):1-25. doi: 10.1007/BF00387687.
Redlight is known to increase the growth potential in the embryo of photodormant lettuce seed, enabling it to overcome the resistance offered by the seed coats (particularly the endosperm) or by an osmotically active medium. Determinations of the water potential of lettuce embryos germinating in osmoticum. carried out with a modified gravimetric technique which eliminates errors intro, duced by solute penetration into cellular osmotic space, showed that the water potential of red-light-treated embryos was lower than that of dark-treated ones, the difference being equivalent to the potential of a 0.30 molal mannitol solution. The force necessary for the radicle to penetrate the seed coats, measured directly, was found to be equivalent to the osmotic potential of 0.16 to 0.38 molal mannitol. Thus red light, acting through phytochrome, induces in photodormant lettuce embryos a decrease in water potential which is equal to that which is required for germination. A mechanism for this phytochrome-induced decrease in water potential is discussed.
红光已知可以增加光休眠生菜种子胚胎的生长潜力，使其能够克服种皮（特别是胚乳）或渗透活性介质的阻力。用改良的重量法测定在渗透物中发芽的生菜胚胎的水势，该方法消除了溶质渗透到细胞渗透空间引起的误差，表明红光处理的胚胎的水势低于黑暗处理的胚胎，差异相当于 0.30 摩尔甘露醇溶液的势。直接测量的穿透种皮的胚根所需的力被发现相当于 0.16 至 0.38 摩尔甘露醇的渗透压。因此，红光通过光敏色素诱导光休眠生菜胚胎的水势下降，其下降幅度等于发芽所需的水势下降幅度。讨论了这种由光敏色素引起的水势下降的机制。
