Variation in net photosynthesis, stomatal characteristics, leaf area and whole-plant phytomass production among ten provenances of neem (Azadirachta indica)

Variation in net photosynthesis, CO2 exchange parameters, stomatal characte ristics, leaf area and seedling dry weight were investigated among 10 prove nances of neem (Azadirachta indica A. Juss.). Significant provenance variat ion was established for net photosynthesis (8.14 to 15.13 mu mol m(-2) s(-1 )). stomatal conductance (0.37 to 0.59 mol m(-2) s(-1)), stomatal density ( 145 to 204 mm(-2)), and total guard cell length (2681 to 3873 Irm). Net pho tosynthesis was positively correlated with whole-plant dry weight and leaf area. Stomatal density was positively correlated with net photosynthesis, w hole-plant dry weight, and leaf area. Total guard cell length was positivel y correlated with all of these traits. Information on six traits was used i n a cluster analysis to construct a dendrogram to assess phenetic relations hips among the provenances. With a few exceptions, the dendrogram revealed three major clusters grouped according to rainfall distribution. The study indicated that whole-plant phytomass production of neem seedlings was assoc iated with photosynthesis and stomatal characteristics during the early sta ges of growth.