Wada Kaede C, Mizuuchi Kaori, Koshio Aya, Kaneko Kentaro, Mitsui Toshiaki, Takeno Kiyotoshi
Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata, Niigata 950-2181, Japan; Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, Ikarashi, Niigata, Niigata 950-2181, Japan.
Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata, Niigata 950-2181, Japan.
J Plant Physiol. 2014 Jul 1;171(11):895-902. doi: 10.1016/j.jplph.2014.03.008. Epub 2014 Mar 29.
The involvement of salicylic acid (SA) in the regulation of stress-induced flowering in the short-day plant pharbitis (also called Japanese morning glory) Ipomoea nil (formerly Pharbitis nil) was studied. Pharbitis cv. Violet was induced to flower when grown in 1/100-strength mineral nutrient solution under non-inductive long-day conditions. All fully expanded true leaves were removed from seedlings, leaving only the cotyledons, and flowering was induced under poor-nutrition stress conditions. This indicates that cotyledons can play a role in the regulation of poor-nutrition stress-induced flowering. The expression of the pharbitis homolog of PHENYLALANINE AMMONIA-LYASE, the enzyme activity of phenylalanine ammonia-lyase (PAL; E.C. 4.3.1.5) and the content of SA in the cotyledons were all up-regulated by the stress treatment. The Violet was also induced to flower by low-temperature stress, DNA demethylation and short-day treatment. Low-temperature stress enhanced PAL activity, whereas non-stress factors such as DNA demethylation and short-day treatment decreased the activity. The PAL enzyme activity was also examined in another cultivar, Tendan, obtaining similar results to Violet. The exogenously applied SA did not induce flowering under non-stress conditions but did promote flowering under weak stress conditions in both cultivars. These results suggest that stress-induced flowering in pharbitis is induced, at least partly, by SA, and the synthesis of SA is promoted by PAL.
研究了水杨酸（SA）在短日植物牵牛（也叫日本牵牛）裂叶牵牛（原名为 Pharbitis nil）的胁迫诱导开花调控中的作用。在非诱导性长日条件下，将牵牛品种紫罗兰种植在 1/100 强度的矿质营养液中可诱导其开花。从幼苗上去除所有完全展开的真叶，仅保留子叶，在营养缺乏胁迫条件下诱导开花。这表明子叶在营养缺乏胁迫诱导开花的调控中可发挥作用。胁迫处理上调了裂叶牵牛中苯丙氨酸解氨酶（PAL；E.C. 4.3.1.5）同源物的表达、子叶中苯丙氨酸解氨酶的酶活性以及 SA 的含量。紫罗兰也可通过低温胁迫、DNA 去甲基化和短日处理诱导开花。低温胁迫增强了 PAL 活性，而 DNA 去甲基化和短日处理等非胁迫因素则降低了该活性。在另一个品种天丹中也检测了 PAL 酶活性，得到了与紫罗兰相似的结果。在非胁迫条件下，外源施用 SA 不会诱导开花，但在两个品种的弱胁迫条件下均能促进开花。这些结果表明，牵牛的胁迫诱导开花至少部分是由 SA 诱导的，并由 PAL 促进 SA 的合成。
