Effects of different mowing treatments and stubble heights on the compensatory growth and quality of lettuce (Lactuca sativa L.)

This study were investigated the effect of mowing method on growth and quality of lettuce. The seedlings after a 24-day incubation in the growth chamber underwent one of six mowing treatments with different stubble heights (i.e. 0.5, 1.0, or 1.5 cm). One mowing treatment group consisted of plants that retained the 2–3 new leaves in the centre (RBL), while the other group consisted of plants in which the new leaves were removed (RBN). Seedlings that were not mowed served as the controls. The results showed that, after seedlings continued to be incubated for 10 days under red and blue light in a growth chamber, the fresh mass of plants and dry mass of shoots were higher for the RBL1.0- and RBL1.5-treated plants than those of the RBN-treated plants. With increasing stubble height, the shoot fresh mass of plants in both mowing groups gradually increased. Mowing decreased chlorophyll (a + b) contents, but did not affect carotenoid levels. Mowing treatments promoted photosynthesis, and did not decrease soluble sugar, sucrose, soluble protein, Vitamin C and anthocyanin contents. Our results implied that mowing treatments promote the compensatory growth of lettuce, and mowing plants to a height of 1.5 cm produces the greatest yield benefit.