Effect of the Seed Ageing of Triticum Durum CV. Cappelli on the Length of Mitotic Cycle as Measured by ³H-Thymidine Incorporation in the Root Meristem

SUMMARY

The duration of the mitotic cycle and its phases was measured in the root tips of two crops (1966 and 1974) of Triticum durum cv. Cappelli, by autoradiographyc technique, after labelling with ³H-thymidine. The average total duration of the mitotic cycle was found to be 18h 45′ in crop 1966 and 16h 25′ in crop 1974. This time included, in crop 1966, a synthetic period (S) of 9h 35′, a post-synthetic period (G₂) of 2h 36′, a mitotic duration of about lh and a pre-synthetic period (G₁) of 5h 36′. In crop 1974, S was found to be 9h 20′, G₂ 4h 30′, mitosis 56′ and G₁ lh 38′. The single phases duration was also considered as percentage of the total time of the cycle.