Dynamics of leaflet elongation and its relationship with plant performance in Rubber (Hevea brasiliensis) trees under dry sub-humid climatic conditions

Leaf growth dynamics may have a bearing on plant performance as they are the major organs of carbon acquisition. aim of this work was to model leaflet elongation pattern and to determine relationship of function parameters/derived growth quantities with growth performance in hevea trees. data were collected from randomly selected six leaflets of three trees from each of nine clones and richards function was fitted. growth quantities,critical points and their coordinates were computed and correlated with girth of clones. leaflet elongation followed a similar pattern irrespective of clone and its duration was short in stress-free period than stress period. most of the correlations were negative except that of second derivative,duration of linear and plateau phases. none of the stress period correlations were significant. variation in leaf elongation rates of individual leaflets appeared to be due to variation in rate of cell division and/or cell elongation. all the sampled leaves of a clone followed a very similar growth pattern suggesting common duration in leaf emergence to full leaf expansion of all the leaves in a given whorl irrespective of leaf size. significant correlation observed for y-axis intercept of phase change point from lag to linear might be useful in identifying high growth clones.