摘要：The aim of this present work is to verify the action of the hydric balance on phyto-sociological and physic-ecological factors in plant from ruderal fragment.It was determined the leaf number (NF), dry weight of leaves (PSF), foliar area (AF) and the weight of the total dry substance (PMSt).With the values of AF and PMST, the growth analysis parameters had been calculated.These phyto-ecological factors are: index of foliar area (IAF), reason of the foliar area (RAF), absolute growth rate (TCA), production of dry substance rate (TPMS), relative growth rate (TCR), assimilating net rate (TAL).Also the phyto-sociological factors had been calculated: relative density (DR), absolute frequency (FA), relative frequency (FR), relative domain (DoR), importance value index (IVI) and relative importance (IR).In accordance with the hydric balance analysis in the region (Vassouras, Rio de Janeiro, 43° 07'' N/22° 08' S), it was observed that the analyzed locality has a period of drought that corresponds from May to September, when the temperature raises.The period of hydric excess is observed from October to January and in April, and in December, the summer time.The total annual average of the precipitation and the average temperature for the locality are, respectively, 1264,7 mm and 25,6° C.It has a hydric annual deficit of 30 mm and an excess of 372 mm.A cause that modifies the use of the LBC (folíolo-pecíolo angle class) in natural conditions is the environmental factors, as temperature, hydric deficit and nutritional state of the plant.Low wf had modified some morphologic parameters in ruderal plants, including the size and the total number of leaves in blossom.The reference value (r) was determined as 30 mm, based on comments on the leaves tissue formation and on growth curves.It is verified that the duration of plastocrono (p/r) was 0,61 per day and the rate of the leaves appearance in the launching is (r/p) 0,83 per day, for hydric excess in the plants under 0,12 deficit met p/r = 0,89 per day and r/p = day.
