Allocation of resources to flowering and fruit production in Hesperaloe funifera (Agavaceae)

Abstract

Hesperaloe funifera has long, thin fibres that can be used to produce paper with exceptional physical properties. Agronomic investigations have shown that the crop can be harvested first after five years, and subsequently every three years thereafter. During the third or fourth year the plants produce a large inflorescence. The objective of this study was to determine the amounts of resources (carbohydrates and nitrogen) consumed during flowering, in order to gauge the potential for shortening the harvest cycle through control of flowering. An average inflorescence in plants flowering for the first time had a mass of 1111 g, which required 1430 g of soluble carbohydrate and 16.9 g of nitrogen. Total carbohydrate stored in such a plant prior to flowering was estimated to be just 570 g, indicating that most of the carbohydrate used to support flowering had to come from current photosynthesis. Estimated N requirements for flowering in four-year-old stands are 165-220 kg N ha-1. Removal or inhibition of developing flower stalks thus would appear to have the potential to redirect considerable amounts of carbohydrate to leaf production and greatly reduce nitrogen fertilizer requirements. (C) 2000 Academic Press.