Lettuce growth inhibition

Growth inhibition of lettuce seedlings and various species — 249,250... 

In some cases light inhibition of hypocotyl or mesocotyl extension can be overcome by lAA (Acton and Murray 1974, Vanderhoef and Briggs 1977). This is the case in lettuce hypocotyls, where the data indicate a correlation between light-induced growth inhibition and both reduced auxin content and apparent reduced sensitivity of the cells to auxin. 

The results of bioassay are shown in Table 1. The synthetic con q)ounds were tested for growth inhibition assay using rice and lettuce. The cyano and diacid analogs were inactive. On the other hand, fluorine analog 3E showed a comparable activity to the parent conq)ound. We interpreted these results as the steric requirement of 2 -position was severe for the activity and electronic change was not so in q)ortant. The results fliat 3Z showed some activity was curious, because 4Z would not isomerize to its -isomer in vivo. 

Diet may counteract or substitute for chemical cues that influence sexual maturation. Male California voles, Microtus californicus, for instance, are inhibited in their sexual development by odors from their mothers or unrelated females. This effect is eliminated if the regular diet is enriched with fresh lettuce. In young females, uterus growth is stimulated by the odor of males but, in the absence of males, fresh lettuce added to the diet can accomplish the same effect (Rissman and Johnston, 1986). This can be seen as another case of adaptive redundancy of cues for an important function. 

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