Quantitative phenology of warm desert legumes: seasonal growth of six Prosopis species at the same site

Non-destructive growth analysis was used to investigate the comparative growth morphology, capability and seasonality of six species of Prosopis grown at the same site. The six species investigated were: P. alba, P. chilensis, P. glandulosa, P. nigra, P. ruscifolia and P. velutina. Plants were derived from seed collected in South America (P. alba, P. chilensis, P. ruscifolia, P. nigra) and North America (P. glandulosa, P. velutina). Three of the species (P. chilensis, P. glandulosa, P. velutina) were used to investigate the influence of water limitation on growth. There were some remarkably similar growth patterns among all species, such as two distinct growth periods, rapid shoot elongation during short periods of the growing season, and all trees were virtually leafless in February through to March. However, each species had a different growth morphology. For example, P. ruscifolia produced long unbranched shoots and an open canopy while P. nigra produced highly branched new shoots and a dense canopy. Water limitation caused a decrease in plant water potential in all three species, but P. ruscifolia had the lowest leaf water potential and the greatest inhibition of growth. In addition, growth analysis of branches indicated that P. chilensis would have the greatest wood production and P. glandulosa the least when grown in these experimental conditions. However, water limitation caused a proportionally greater decrease in P. chilensis growth than that of P. glandulosa, and water limitation induced an increase in fruit production in P. glandulosa.