Morpho-physiological changes of Prosopis laevigata (Humb. & Bonpl. ex Willd.) M.C. Johnst. seedlings to different nursery light environments

Abstract

In order to determine if the management of nursery light conditions has potential to manipulate morpho-physiological characteristics of seedling quality, in this study the morpho-physiological changes of Prosopis laevigata seedlings subjected to varied light environments, both under full sun and shading with nets of different colors (blue, black, red, and green) during nursery production, are measured. We evaluated their growth, in terms of biomass gain per seedling; their morphology, trough biomass allocation patterns, and by calculating the specific leaf area, and their photosynthetic efficiency as net assimilation rates. Seedling grown under red net attained the highest growth, 24 % higher compared to seedlings grown under full sunlight. Biomass allocation patterns were affected. Under full sun, the seedlings allocated less than 50 % of the total biomass to shoot and increased proportionally the root biomass, whereas a shading with nets, regardless of their color, inverted the patterns, promoting a higher biomass allocation to the shoot (more than 60 %). Under full sunlight, specific leaf area diminished, but under shading it increased up to 106 % under the black net. The higher net assimilation rates were obtained by seedlings under full sunlight; however, better photosynthetic efficiency was achieved by seedlings grown under the red net due to their higher growth. It is concluded that it is possible to manipulate the morpho-physiological characteristics of P. laevigata seedling quality by managing the nursery light conditions.