Nucleic acid changes in three carrot cultivars infested with Meloidogyne incognita

Nucleic acid content in galls of all the three carrot cultivars-Early Nantes (highly susceptible), pusa Kesar (moderately susceptible) and Black (moderately resistant) was higher as compared to their healthy roots. In galls, RNA and DNA were concentrated more in giant cells and the nematode bodies. RNA was localized in nucleoli, nuoleoplasm and cytoplasm and its amount increased as the syncytium developed and decreased only when it degenerated. The intensity of feulgen stain, depicting the presence of DNA, paraBeled the nuclear volume which was maximum in syncytium associated with the spike-tail stage of larva. The giant cells of the same complex stained differently for DNA. The syncytial nuclei were larger and lobed in susceptible cultivars, Pusa Kesar and Early Nantes than in moderately resistant cultivar Black.