Abstract:

To study the change rules of leaf area and dry matter weight of cucumber with different leaf ages under low temperature and weak light stress, cucumber variety Biyu 3 was used as the test material, four treatment levels of low temperature and weak light were set, changes of leaf area, dry matter weight with different leaf ages were measured. The results showed that low temperature stress had a great effect on morphological development of leaves less than 15 days old, compared with the control, the decrease of leaf area was relatively large, but the effect on leaves aged 15-25 days was small; Under moderate low temperature (10-15 ℃) and weak light (photosynthetic photon flux density, PPFD 100-200 μmol·m^-2·s^-1), growth of leaf area decreased significantly and dry matter weight of leaves increased in the extension stage (5-15 d); The morphological development of leaves less than 15 days was basically stagnated under severe low temperature (5-10 ℃) and weak light (0-100 μmol·m^-2·s^-1), compared with the control, the decrease of leaf dry matter weight was relatively large; Mild low temperature and weak light stress (15-20 ℃, PPFD 200-400 μmol·m^-2·s^-1) did not significantly threaten the normal development of cucumber leaves, especially had little effect on the growth of leaf area and dry matter accumulation at the early stage of development. The results showed that in order to ensure the normal growth of leaves from the early stage of development to the expansion stage, moderate or above low temperature and weak light stress (5-15 ℃, PPFD 0-200 μmol·m^-2·s^-1) should be avoided.

Key words: cucumber, low temperature, weak light, leaf area, dry matter