Photosynthetic capacity, photochemical efficiency and chlorophyll content of three varieties of Labisia pumila Benth. exposed to open field and greenhouse growing conditions

Three varieties ( Alata , Pumila and Lanceolata ) of Malaysian indigenous medicinal herb Labisia pumila Benth. grown in greenhouse and open field were tested to evaluate and compare their photosynthetic and maximal quantum efficiency of photosystem II ( F v / F m ) reactions. Every variety grown in greenhouse demonstrated higher light-saturated photosynthetic capacity than in the open field. The diurnal net photosynthesis ( A ) curve in the open field also displayed dual peaks with lower daily average A compared to the greenhouse. Varieties Alata and Pumila were found to acclimatize better under both growing conditions. The diurnal patterns of F v / F m indicated that plants grown under greenhouse encountered less photoinhibition than in open field condition. A decrease in chlorophyll (chl) a / b ratio in leaves of greenhouse plants with significant increase in chl b was observed. This study indicates that var. Alata and var. Pumila have the capacity to acclimatize to greenhouse growth condition.