Effects of Dissolved Oxygen on Growth, Photosynthesis and Yield of Leaf Lettuce
MA Jimei
TIAN Juncang
ZHANG Ruiwan
Abstract：We studied the impact of dissolved oxygen concentration in irrigating water on growth, photosynthe-sis, fresh weight,dry weight and yield of leaf lettuce grown in a greenhouse. Four concentrations were examined:6.8 mg/L (T1), 8 mg/L (T2), 7.4 mg/L (T3) and 1.2 mg/L(T4). The findings were as follows:①The dissolved ox-ygen concentration has a significant impact on lettuce height, leaf numbers and stem diameter;both height and leaf number of the lettuce under different treatments decreased in the order of T2>T3>T1>T4.②The dissolved oxygen concentration also has a significant effect on chlorophyll content, net photosynthetic rate, transpiration rate, and stomatal aperture, but has less impact on intercellular CO2 concentration.③The dissolved oxygen has re-markable impact on fresh and dry plant weights. The highest fresh weight and dry weights were in T2, being 56.25 g and 10.71 g respectively. The lowest fresh and dry weights were in T4, being 42.64 g and 3.52 g respec-tively. The yield in T1, T2 and T3 increased by 13.2％, 22.6％and 28.3％respectively compared with that in T4. The results showed that a combination of dissolved oxygen concentration of 7.4 mg/L with amount of irrigation of 45 m3/hm2 achieved the highest yield.
Keywords：water saving irrigationdissolved oxygen concentrationleaf lettucephotosynthesis indexesyield
Publication Date：2017-01-01
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：6( 60-65 )