The effect of rootstock on leaf characteristics and physiological response of satsuma mandarins under saline conditions

Along the sea line, salinity problems arise in satsuma production due to sea water intrusion in Turkey. To overcome, resistant rootstocks can be used. The findings related to the response of the two major rootstocks, troyer citrange and trifoliate orange under saline conditions are not always in harmony. To generate new alternatives to overcome salination, a trial was set up in 1996 at Ege University Department of Horticulture (Bornova-Izmir/Turkey) with satsuma mandarin cv. Owari budded onto two rootstocks, trifoliate orange and troyer citrange and irrigated from June to October at 5 salinity levels (0.65; 2.00; 3.50; 5.00 and 6.50 dS/m) as triple line source. In 1996 and 1997, leaf characteristics, area, number of stomata, relative water content and succulence index were determined monthly during the summer months. Leaf CO2 exchange was determined by using a CI-301 PS (CID, Inc.) photosynthesis system and leaf water potential by a pressure chamber apparatus (PSM Inst). The obtained results showed that increased salinity in irrigation water exerted significant effects on leaf area, dried matter and succulence index. Relative turgidity values were found to vary significantly for all variables except the sampling date. Net photosynthesis rate was also suppressed. The effects on trifoliate orange were more apparent than troyer citrange.