Effect of Temperature on the Fruiting of Poinsettia

Abstract

溫度對聖誕紅花粉發芽影響很大，在15℃環境下花粉並不會發芽，大部分品種花粉發芽最適的溫度是在23℃。庭園栽培種、艾基-自由品種、艾基-來樂紅品種，均是花粉發芽率較高的品種，授粉後也可得到種子。反之安妮-星光品種及新大禧品種花粉發芽率低。彼得之星品種更嚴重不僅花粉量少，授粉後也未見花粉在柱頭上發芽。具親和性的親本授粉後經3-5天花粉管可到達子房內，而花粉管伸長的速度與溫度有關。第一年春季授粉比冬季授粉的著果率高；同在冬季授粉著果率第二年授粉著果率為第一年著果率之18倍。而第二年冬季之平均溫度比第一年高2-3℃。又授粉後5天內維持平均溫度在21-23℃，授粉的著果率較高。

Pollens germination was affected by temperature. Under the temperature of 15℃, pollens did not germinate. The optimum temperature for most of poinsettia pollen germination was at 23℃. Not only had the highest pollen germination rate but seeds harvested of poinsettia cultivars occurred in ‘Garden cultivar',‘Eckespoint Freedom'and ‘Eckespoint Lilo Red'. On the other hand, the lowest of that occurred in‘Annette Hegg Diva Starlight'and ‘Petoy'. The most difficult for breeding was on ‘Jacobsen Petersta', it had few pollens and the pollen did not germinate on style. The successful pollination was also around 23℃. Pollen tube of a successful pollination entered ovule after the 3-5th day. the speed of pollen tube growth related to temperature. The rate of fruit set in the second winter was eighteen times than the first winter, as well as the average temperature was 2-3℃ higher than the first winter. The rate of fruit set was higher when the average temperature was at 23℃ from pollination to the 5th day after.