PARTICIPATION OF SEMINAL ROOTS IN WATER-UPTAKE BY MAIZE ROOT-SYSTEM

The water uptake (WU) by seminal part (RS) and vegetative nodal part (RAN) of the maize (Zea mays L., hybrid CE 330) root system was separately measured during growing season using method of compensation lysimetry. In average, WU by RS was observed 16.7% of total amount of plant water uptake during growing season. The relative water uptake (WU in %) by RS has decreasing tendency in total WU by plant, from 100% plant WU in time of germination to about 10% plant WU in early phase of grain feeding by assimilates. This general tendency was twice interrupted, first by preliminary increase of WU just before flowering, and second by most expressively increase of WU in time of cob increment. The rate of water uptake (RWU in ml m-2 d-1 1-degrees-C) was determined up to six fold higher in RS than in RAN during generative phase. RWU by RAN was positively correlated with changes of shoot:root surfaces ratio, while RWU by RS was positively correlated with dry matter increment of cob.