Response of rose apple (Eugenia jambos L.) to water and nitrogen supply

The combined effect of water and nitrogen (N) on growth and gas exchange ch aracteristics of rose apple cuttings (Eugenia jambos L.) was investigated. The experiment consisted of four treatment combinations: adequate watering (AW = 450 mi nutrient solution) and inadequate watering (IW = 150 mi nutrie nt solution) with or without 8 mM N as NH4NO3. Soil moisture tension prior to the irrigation cycles ranged from 0.003-0.00 9 MPa for AW and from 0.028 to 0.05 MPa for IW. Growth analysis showed that water stress affected plants more severely than N stress. Irrespective of N-supply, adequately-watered plants exhibited high photosynthesis rates (P- N) and were more vigorous. The length of the internodes, formation of secon dary branches, leaf number and total leaf area were enhanced. Under water s tress more dry matter was allocated to the root system. There was a signifi cant reduction in leaf number, total leaf area and number of secondary bran ches. Addition of N had a compensating effect on the reduction of dry matte r production in the presence of water stress. This was indicated by a 20 %, 18 % and 33 % increase in shoot length, leaf number and leaf area, respect ively.