摘要
茶树叶片光合日变化,双峰和单峰型都有出现。强光的光抑制是形成“午休”的主要原因:高温是午休的部分成因:光温适宜,低湿对“午休”的形成影响不大。强光下,伴随高温、低湿条件加剧强光的光抑制,光合日变化的第二个峰很不明显,整个下午光合速率很低。预遮光(黑暗或减低光强)和遮荫时的光合速率明显提高;夏季阴天时光合日变化呈单峰型;在恒定的适宜光温下,光合速率不发生中午降低。茶树光合日变化可以人工调控。本文为提高茶树光合速率,提高了控制途径。
Net photosynthetic rate(Pn)of tea leaves was measured with an infrared gasanalyser and also with half leaf method under conditions of different light intensity,temperature,air humidity and CO_2 concentration to investigated the cause of middaydepression.It was observed that the optimum temperature and light saturation pointof photosynthesis in tea leaves varied with seasons.The optimum temperature rangedfrom 15 to 30℃,At 35℃,the photosynthesis decreased sharply.Light saturationpoint ranged from 300 to 750 μmol photons m^(-2)s^(-1).Both double peak and single peak curves of diurnal course in photosynthesis wereobserved.Pn remained constant as long as light intensity (Lower than the lightsaturation point),temperature(Lower than the optimal temperature) and CO_2concentration remained constant.Evidently,the phenomenon of midday depression isnot due to endogenous rhythm.It is suggested that the midday depression ofphotosynthesis in tea leaves is mainly due to photoinhibition.High temperature andlow humidity strengthen the inhibition of photosynthesis under strong light.It is proposed that strong light is one of the most important factors causing mid-day depression.Possible ways of enhancing the photosynthesic efficiency of tea plantare also discussed.
出处
《作物学报》
CAS
CSCD
北大核心
1991年第6期444-452,共9页
Acta Agronomica Sinica
关键词
茶树
光合日变化
光抑制
Tea plant
Diurnal variation
Midday depression
Photoinhibition
Photosynthetic activities
