Explant cultures of maize (Zea mays L.) raised under water‐deficit and waterlogged conditions

Abstract

summaryRoot‐tip segments excised from plants grown under conditions of water deficit and waterlogging did not exhibit any significant change in the extent of callus induction over controls when cultured on Murashige and Skoog's (MS) medium supplemented with 2,4–D alone or in combination with L‐proline. On the other hand, the mesocotyls cultured on medium with 2,4–D showed an increase in the extent of callus induction which was further improved by the addition of L‐proline. The root tip callus from plants grown under water deficit conditions showed increases in both fresh and dry weight over controls on MS medium supplemented with 2 mg 1–1 2,4‐D while mesocotyl segments from plants grown in the presence of 5 % polythylene glycol‐6000 produced heavier calli on 2,4‐D supplemented media. The addition of L‐proline to the medium favoured an increase in both fresh and dry weights of root tip callus but failed to bring about a similar change in mesocotyl callus.Waterlogging pre‐treatment resulted in an increase in fresh weight of root tip callus over control on 2,4‐D supplemented medium but not with the mesocotyl callus. Further, addition of proline to the medium enhanced both fresh and dry weights of root tip callus but did not affect the weights of the callus of mesocotyl origin. The pre‐conditioning treatment did not modify the regeneration potential of the explants. The biochemical basis of such a differential behaviour of the two explant types is discussed in the light of available information.