Effect of nutrient solution on growth and some physiological characters of hydroponically grown lettuce

Lettuce is one of the major leafy vegetables that is consumed as fresh and salads crops. Although، today، the tendency is to grow lettuce as hydroponic crop، there is not an optimal nutrient solution and growers use different nutrient solutions for growing lettuce. Therefore، an experiment was conducted to find an optimal nutrient solution to grow lettuce. In this experiment، the effect of various important nutrient solutions including، NSHog، NSKnop، NSUK، and NSU. T on two cultivars of lettuce (Siahoo and Conquistador) was investigated. The experiment was arranged in the randomized completely block design with four replicates and traits i. e.، chlorophyll index، photosynthetic efficiency، tip burn، fresh and dry weight، leaf area، and number of edible leaves were assessed. Plants were sown in the media containing perlite and then irrigated with nutrient solution manually. The results showed that nutrient solution had significant effect on the yield and some of the growth characteristic of lettuce. Plants grown in the UK solution had the highest fresh and dry mass، leaf area، and the number of edible leaves. The lowest fresh and dry weight، leaf area and the number of edible leaves was obtained in plants supplied with UT solution. Results also showed significant variation between two cultivars. Siahoo had higher fresh weight، leaf area، and the number of edible leaves than conquistador. Interaction between cultivar and nutrient solution had significant effect on chlorophyll index. According to the results obtained، UK nutrient solution was the best nutrient solution for lettuce production.