Photosynthetic efficiency, canopy micro climate and yield of rejuvenated guava trees.

摘要

Sixteen-year-old dense orchard of guava cultivars Allahabad Safeda and Sardar spaced at 5.0x5.0 m were taken and trees were topped at different heights (1.5, 2.0 and 2.5 m from ground level) in May 2002, at Lucknow, Uttar Pradesh, India. After the emergence of new shoots as a result of topping, hedging treatments were given in the month of October 2002, May 2003 and October 2003 and this was continued up to 2004. Physiological and microclimate observations such as net photosynthesis (A net), stomatal conductance (gs), light penetration, internal leaf temperature and relative humidity were measured periodically in leaves of flowering and non-flowering branches of the rejuvenated trees in each cultivar and compared with control. The level of A net was more pronounced in flowering branches of tree which was topped from 1.5 m height as compared to the non-flowering ones in both cultivars. However, no such significant difference was seen in stomatal conductance. Light penetration was greater in 1.5 and 2.0 m height pruned trees internal relative humidity of leaf was highest under the control (no pruning) and decreased with the increase in pruning intensity. Canopy temperature was maximum in rejuvenated orchard and lowest in control. Fruit yield increased to the tune of 75 to 80 per cent in rejuvenated orchard over the control trees..