اثر تنش خشكي بر رنگيزه هاي گياهي، پرولين، قندهاي محلول و پارامترهاي رشد چهار گونه از اكاليپتوس

Effects of drought stress on pigments, prolin, soluble sugar and growth parameters on four eucalyptus species

Physiological reaction of different Eucalyptus species to drought stress can help to recognize effective mechanisms in drought stress and choose the best species for planting in dryland of Iran. This study was carried out with polyethylene glycol 6000 as diminutional osmosis with different drought stress treatments: 0, -0.1, -0.3, -0.6 and -1.2 MPa on established seedling in hydroponic culture in greenhouse. Factorial experiment, based on a completely randomized block design with three replications was tested on Eucalyptus camaldulensis, E. microtheca, E. meliodora and E. viminalis. Sampling were carried out from stamen leaves of different treatments and pigments concentrate (total chlorophyle, chlorophyle a, b and carotene), soluble sugar, prolin and growth parameters included biomass, leaf area, relative water content (RWC), water saturation different (WSD), specific leaf area (SLA), leaf water content per unit leaf area (LWCA) were calculated. Increased drought stress led to increase in prolin, soluble sugar and decrease in pigments and growth parameters at four species. Prolin and soluble sugar have important plane in osmosis regulation and osmosis protection so increase in content of these substance led toletance of plant again osmosis stress. Decrease in pigments is because of decomposition enzymes activitiy. E. microtheca was the most tolerant species to drought stress, although had the highest quantity of prolin, soluble sugar, pigments, biomass, LWCA and RWC.