Abstract: The effect differences of nitrogen forms,10 mmol/L nitrate nitrogen(N10)and 5 mmol/L nitrate nitrogen combined with 5 mmol/L ammonium nitrogen(N5+A5),on spectral absorbance,yield and quality responses of three leaf-color lettuces.The results showed that spectral absorbance was influenced by nitrogen form and the cultivars of lettuce.The spectral absorbance was greatly increased under N10 treatment compared with N5+A5 treatment.However,the chang trend of spectral absorbance curves of three leaf-color lettuces was not distinctly effected by nitrogen form.The contents of photosynthetic pigment were strikingly promoted when supplied with N10.On the contrary,significant decreases were found in shoot fresh weight,shoot dry weight and root cap ratio under N10 treatment.There was no remarkable difference in contents of flavonoid and anthocyanin between the two nitrogen form treatments.However,the total phenols contents of green lettuce and red lettuce were slightly improved when supplied with N10.And the ascorbic acid content of green lettuce was prominently enhanced by N10 treatment.These results indicated that nitrate nitrogen remarkably influenced the spectral absorbance and yield of three leaf-color lettuces,and the effects differed between cultivars.Regulating nitrogen form and light environment based on different color lettuce was a feasible approach to promote the yield and quality of different color lettuce.

Key words: Lettuce, Leafy color, Nitrogen form, Spectral absorbance curve, Antioxidant substance

CLC Number: 

• S143.1