Differential Effect of Day and Night Temperature Regimes on the Growth and Biochemical Attributes of Violet Rape (Brassica campestris ssp. chinensis L.)

摘要

The present study investigated the influences of different day and night temperature regimes on the growth of violet rape (Brassica rapa var. chinensis) and pinpointed the optimal temperature combination for both yield and quality of the plant. For this purpose, the plants were grown under 6 temperature combination conditions: W1 (30/20 degrees C, 12-h light/12-h dark), W2 (25/15 degrees C, 12-h light/12-h dark), W3 (20/10 degrees C, 12-h light/12-h dark), W4 (30/15 degrees C, 12-h light/12-h dark), W5 (25/10 degrees C, 12-h light/12-h dark), and W6 (30/10 degrees C, 12-h light/12-h dark), and in addition we measured various morphological, yield, and biochemical traits. Results demonstrated that temperature regimes considerably affected the growth parameters of the violet rape compared with control. The W3 treatment with an average temperature of 20/10 degrees C displayed the highest plant growth traits, including plant height (12.74 +/- 0.24 cm), leaf length (8.20 +/- 0.08 cm), leaf width (5.44 +/- 0.16 cm), and leaf area (33.46 +/- 0.83 cm (2)). Moreover, a highly significant correlation (p0.05) was found between temperature and soluble protein, chlorophyll, anthocyanin, nitrate nitrogen contents, and root activity; whereas the vitamin C and soluble sugar contents remained significantly unaffected except in the W1 treatment, under different temperature combinations between day and night. This study concluded that high temperature exerts an adverse effect on plant growth, and therefore a low day and night temperature combination is suggested in order to achieve high yield and quality for irrigated violet rape.