CHANGES IN ENDOGENOUS GROWTH REGULATING SUBSTANCES IN THE MANGIFERA INDICA L. SHOOT IN RELATION TO GROWTH AND DEVELOPMENT
Well established trees of Langra (biennial) and Baramasia (perpetual) were selected for this study. The experiment was conducted during the years 1967–68 and 1968–69. The first sample of 1967–68 was taken in April when the first flush of spring growth in Langra came to a cessation and a second sample in June when there was no further flush of growth. The third, fourth and fifth samples were collected from ringed (ringing in June) and non ringed branches in October, November and December, respectively to cover the period of floral differentiation. In the following spring 60 per cent of shoots on ringed branches and only 3.3 per cent on non ringed branches produced flowers. Samples of Baramasia were taken on the same dates as in Langra. There was no ringing treatment in Baramasia. In this variety 50 per cent of terminal spring shoots flowered in May and 90 per cent of laterals appearing on the shoots which flowered in May, bore flowers through autumn-winter.
In 1968–69 current years growth was sampled during the period from March to January in both the varieties. With the view to suppressing growth and inducing flowering, Langra shoots were ringed in the second week of April, 1968. In this year also no such ringing operation was done in Baramasia as this variety normally flowers freely.
In Langra samples were collected in March, April, August, October,