Photothermal Induction of Flower Head Formation in Broccoli Plants

Abstract

Effects of growing temperatures (17°C-23°C) and day lengths (8 hours day length and 16 hours day length) on floral development was investigated. Thirteen broccoli cultivars differing in earliness of flower head formation were used. 1. Two extremely early cultivars (`Gokuwase-midori' and`Greenand`Green Comet'), three early cultivars (`Shaster', `Ryoku-yo' and`Satoand`Sato-midori'), and an intermediate culti-var (`Ryoku-zan'), did not form flower heads under short-day conditions at tempe-ratuers of about 20°C, but they formed flower heads long-day conditions at the same temperature. 2. Two extremely early cultivars (`Gokuwase-midori' and Dark Horse'), three early cultivars (`Wase-midori', `Shaster' and`Ryokuand`Ryoku-yo'), and an intermediate culti-var (`Three Seven'), formed flower heads one week earlier under long-day conditions than short-day conditions at arund 17°C. 3. When two early cultivars (`Wase-midori' and`Shasterand`Shaster'), and two intermediate cultivars (`Ryoku-rei' and`Threeand`Three Seven'), formed flower heads at temderatures of about 17°C, the number of leaves to flower heads was smaller under long days than under short days. 4. From these results, it may be considered that the low temperature treatment under long-day conditions promotes flower head formation more effectively than the same treatment under short-day conditions, and the temperature for photother mal induction is somewhat higher than for thermoinduction. As for photothermal induction of flower head formation in broccoli plants, it is estimated that low temperature treatment is more effective than long-day treatment. •• OE¾ ƒu ƒ• ƒbƒRƒŠ•[ ‚Ì ‰Ô ‚ç ‚¢OE`•¬ ‚É'Î ‚· ‚é'á ‰·-v ‹• •« ‚ÉŠÖ‚µ ‚Ä‚Í Šô‚‚©‚Ì •ñ •• ‚ª ‚ ‚è(2,3,12,21),ƒJ ƒŠƒt ƒ‰ƒ• •[ ‚AE "¯-l‚É•A•¨ 'Ì •t ‰» OE^‚Ì 'á ‰·-v ‹• •« ‚ð ‚à‚‚AE‚³ ‚ê ‚Ä‚¢ ‚é. ‚½‚¾,•t ‰» •ˆ-• ' † ‚Ì "ú'· •ˆ-•‚Ì ‰e ‹¿ ‚ɂ‚¢ ‚Ä‚Í,ˆÙ ‚È‚Á ‚½OE‹‰Ê ‚ª •ñ •• ‚³ ‚ê ‚Ä‚¢ ‚é.‚ ‚Ü ‚è,Fontes‚ç(2)‚Í, ƒuƒ• ƒbƒRƒŠ•[ ‚Ì ‰Ô ‚ç‚¢ ‚ª "ú'· ‚AE ‚Í-³ ŠÖOEW ‚É'á ‰· •ˆ-•‚É‚ae ‚èOE`‚èOE`•¬ ‚³ ‚ê ‚é ‚AE‚µ‚Ä‚¢ ‚邪,Gauss‚AETaylor(4)‚Í '· "ú•ðOE•‚ª ‰Ô ‚ç‚¢OE`•¬ ‚ð '£ •i ‚· ‚é ‚AE‚µ‚Ä‚¢ ‚é. ‚Ü‚½,•™ ŽR•E•‚ ‹´(19)‚AE ŽÂ OE´(16)‚Í,ƒu ƒ• ƒbƒRƒŠ •[ ‚Ì '• • ¶ Ží ‚Í "ä Šr "I •‚ ‰· •ðOE•‰º‚Å‚à‰Ô ‚ç‚¢ ‚ðOE`•¬‚· ‚é ‚± ‚AE ‚© ‚ç,‚» ‚ê ‚ª 'á ‰·-v ‹• •« ‚ð ‚à‚‚± ‚AE ‚ɂ‚¢ ‚Ä‹^-â ‚ð'ñ Ž¦ ‚µ ‚Ä‚¢ ‚é."¡-Ú(3)‚Í '• "Ó• ¶ ‚ÌˆÙ‚È‚ÌˆÙ‚È ‚é ƒuƒ• ƒbƒRƒŠ •[ ‚Ì •" •i Ží ‚ð-p ‚¢,‚· ‚× ‚Ä‚Ì •i Ží ‚ª 'á ‰·-v ‹• •« ‚ðŽ• ‚‚± ‚AE ‚ð•ñ •• ‚µ‚½.•X ‚É,‹Ÿ ŽŽ‚µ‚½3•i Ží ‚ɂ‚¢ ‚Ä,‰· "x ‚AE"ú'· ‚Ì ŠÔ ‚É‰Ô ‚ç‚¢ OE`•¬ ‚É'Î ‚µ‚Ä'Š •ae•ì-p ‚ª "F‚ß ‚ç‚ê,'· "ú•ð OE•‰º ‚Å‚Í ‰Ô ‚ç ‚¢OE`•¬ ‚Ì ‰Â "\ ‚ȉ· "xˆae‚ª ‚â ‚â •‚ ‚-‚È ‚é ‚± ‚AE ‚ð-¾ ‚ç‚©‚É ‚µ‚½. ‚± ‚± ‚Å‚Í,ƒu ƒ• ƒbƒRƒŠ•[ ‚Ì '• "Ó• ¶ ‚ÌˆÙ‚È‚ÌˆÙ‚È ‚é13•i Ží ‚ð-p ‚¢,‰Ô ‚ç ‚¢OE`•¬ ‚É'Î ‚· ‚é'á ‰·‚AE '· "ú‚Ì 'Š •ae•ì-p ‚É‚¨‚¯‚É‚¨‚¯ ‚é •i Ží ŠÔ•· ˆÙ‚ɂ‚¢ ‚Ä'² •¸ ‚µ‚½OE‹‰Ê ‚ð•ñ •• ‚· ‚é. •Þ-¿‹y ‚Ñ •û-@ ŽÀOE±1. ‹ŸŽŽ•Þ-¿ ‚É‚Í ‹É'• • ¶ ‚Ì`‹É '• • ¶-Î'‚AE`ƒO ƒŠ•[ ƒ"ƒRƒ• ƒb 0 1987"N3OEŽ30"ú Žó-• ƒnƒi ƒ"ƒTƒC-Þ ‚Ì ‰Ô ‚ç‚¢ OE`•¬•À‚Ñ‚É"-ˆç ‚Ì ‰· "x•ð OE•‚É ŠÖ ‚· ‚éOE¤ ‹ †('ae5•ñ) *OE» •Ý "¿ " ‡OE §-• •Z •• ‹y •Š