胡麻臺南1號不同生育時期之光合作用生理變化

Abstract

胡麻 (Sesamum indicum L.) 為國內主要油料作物之一，為了解該作物於不同生育時期的光合作用生理變化，分別於營養生長期、始花期、開花盛期、蒴果充實期及成熟期調查胡麻臺南1 號植株葉片之光反應曲線及各項光合作用參數。結果顯示，於光度1300 μmol m-2s-1 下，胡麻於營養生長期及始花期有較高的光合作用速率 (A1300)、蒸散作用速率 (E1300) 及氣孔導度(g1300)，但水分使用效率 (WUE) 較低，而隨著生育日數的增加，光合作用速率顯著逐漸降低；另由各生育時期的植株葉片光反應曲線顯示，始花期的光飽和淨光合作用速率 (Amax)、光補償點 (LCPT) 及光飽和點 (LSPT) 顯著高於其他時期，而隨著生育日數的增加，Amax 及LSPT皆顯著降低，各生育時期間的呼吸作用(Rd)則沒有顯著性差異。 Sesame is one of the important oil crops in Taiwan. In order to understand the photosynthetic physiology at different growth stage, we measured the light response curve and some photosynthetic characters at vegetative stage, early bloom stage, mid bloom stage, late bloom stage and physiological maturity stage. The results indicated that there were the higher photosynthetic rate (A1300), transpiration rate(E1300) and stomatal conductance (g1300) at vegetative stage and early bloom stage and lower water use efficiency (WUE) than other growth stages, and photosynthetic rate decreased gradually as the number of growth days increased. In the result of light response curve at different growth stage, the light-saturated photosynthetic rate (Amax), light compensation point (LCPT) and light saturation point (LSPT) at the early bloom stage were significant higher than other growth stage, also Amax and LSPT decreased gradually as the number of growth days increased. There is no significant difference in respiration rate (Rd) during each different growth stage.