Growth responses and accumulation of soluble sugars in Inga marginata Wild. (Fabaceae) subjected to flooding under contrasting light conditions.

B Bender,J Sentkovski,L M G Rosa,T L Sausen,M E Lottici,A A Mielniczki-Pereira,E S Capellesso

doi:10.1590/1519-6984.11315

Abstract

Flood events in riparian forests of southern Brazil, can be characterized as unpredictable and of low magnitude with an average duration of less than 15 days. Inga marginata is an evergreen tree which grows in Southeast South America on a wide range of environments, including riparian forests. In this paper, the interactive effects of the light environment and soil flooding on morphological parameters of I. marginata were examined. Seedlings were acclimated in two contrasting light conditions: sun or shade for 30 days. Sun and shade plants were subjected to soil flooding for two periods; five or 15 days. After 5 days, the interaction between flooding and light did not affect growth, chlorophyll content and dry mass or the root-shoot ratio. After 15 days, flooded plants from the sunny treatment had a lower shoot dry mass compared to control sun plants and flooded plants from the shaded treatment. Moreover, the higher dry mass observed for shade plants compared to sun plants, following flooding, can also be directly associated with a higher content of soluble sugars. Shade plants of I. marginata showed a greater acclimation to soil waterlogging. This acclimation appears to be associated with a larger accumulation of soluble sugars compared to non-flooded plants. The responses observed on the shade plants appear to be decisive to indicate the use of I. marginata in degraded areas.

Highlights

Riparian forests are formations adjacent to watercourses, with environments marked by exposure to frequent flooding (Naiman et al, 1998)
The ability of a given species to acclimate to sun or shade conditions can be demonstrated by an assessment of the initial growth under different light conditions, primarily through the analysis of the cost-benefits associated with the observed responses (Givnish, 1988)
During the initial growth, it was observed that Inga marginata seedlings grown under shade conditions had larger leaf area, shoot height and root length, accompanied by a higher shoot dry mass compared to roots and a higher chlorophyll content index compared to sun plants (Table 1)

Summary

Introduction

Riparian forests are formations adjacent to watercourses, with environments marked by exposure to frequent flooding (Naiman et al, 1998). In the riparian forests of the Alto Uruguay region, in southern Brazil, the flood events can be characterized as unpredictable and of low magnitude, showing a reduced water column height, and with an average duration of less than 15 days, and can occur several times throughout the hydrological year (Budke et al, 2010). Flood has a significant impact on the growth of some tree species, it is not the only parameter that determines their growth rate and establishment in riparian forests (Maurenza et al, 2012). Flood has a significant impact on the growth of some tree species, it is not the only parameter that determines their growth rate and establishment in riparian forests (Maurenza et al, 2012). Giehl and Jarenkow (2008) observed that floods, in riverine forests of Rio Grande do Sul, cause selectivity and usually result in the predominance of pioneering species in areas with frequent floods

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