Seasonal changes in perennial nodules of beach pea (Lathyrus maritimus [L.] Bigel.) with special reference to oleosomes.

Beach pea (Lathyrus maritimus [L.] Bigel.), a potential cold‐climate circumpolar legume crop, grows along the shorelines of Newfoundland, Canada. The nodules undergo winter dormancy and become active in the spring season. The nodules sampled in winter show dormant tissue and bacteria without any loss of structural integrity. In the senescent zone, bacteroids are found to be disintegrated. Oleosomes (lipid bodies) are clearly localized in the meristem, invasion zone, interstitial cells of the symbiotic and senescent zone, vascular tissue, and cortical cells of both winter and summer nodules. In all the tissues, significantly large numbers of oleosomes are seen in histological preparations of nodules sampled in winter compared with nodules sampled in summer. As winter approaches, the nodules show increasing accumulation of lipids. The nodule tissues are protected from winter stress and pathogen attack by suberized peridermal cells. We propose multipurpose functions of oleosomes in root nodules of beach pea,...