Abstract:

In this study, the dynamic changes of chlorophyll, photosynthetic rate and dry matter accumulation of flax were investigated. Suitable water amount and drought stress were used as the main factors, and fertilization was used as the secondary factor (pure nitrogen: 60, 90, 120 kg/hm²; P₂O₅: 30, 60, 90 kg/hm²) to measure the chlorophyll content, photosynthetic rate and dry matter accumulation at seedling stage. The results showed that there were significant differences in chlorophyll content under different fertilization treatments. Under drought condition, the chlorophyll content of N1P2 treatment (pure nitrogen 60 kg/hm², P₂O₅ 60 kg/hm²) was the maximum of 0.97 mg/g, under appropriate water treatment, the highest chlorophyll content was observed in N1P2 as 1.189 mg/g. There were significant differences in the photosynthetic rate of each fertilization combination, under the drought stress and appropriate water treatment, the photosynthetic rate of N1P2 reached the maximum value of 16.06 and 17.969 mol/(m²·s), respectively. In addition, there were significant differences in dry matter accumulation among different fertilization treatments under drought stress and appropriate water treatment, the dry matter accumulation of N1P2 was the largest, 0.183 and 0.256 g/plant, respectively. Under drought stress, the photosynthesis of flax could be weaker than that under water treatment, and the appropriate nitrogen and phosphorus application could significantly improve the photosynthetic rate and increase the accumulation of dry matter.

Key words: Flax, Water and Fertilizer Coupling, Chlorophyll, Photosynthesis, Photosynthetic Rate, Dry Matter