Survival strategies of <i>Centrosema molle</i> and <i>C. macrocarpum</i> in response to drought

Authors

  • Orlando Guenni Universidad Central de Venezuela (UCV), Facultad de Agronomía (FAGRO), Maracay, Venezuela.
  • Eva Romero Universidad Central de Venezuela (UCV), Facultad de Agronomía (FAGRO), Maracay, Venezuela.
  • Yajaira Guédez Universidad Central de Venezuela (UCV), Facultad de Agronomía (FAGRO), Maracay, Venezuela.
  • Mercedes P. Macías Instituto Nacional de Investigaciones Agrícolas (INIA), Maracay, Venezuela.
  • Diógenes Infante Programa Prometeo, Senescyt, Ibarra, Ecuador.

DOI:

https://doi.org/10.17138/tgft(5)1-18
Abstract Authors How to Cite

Abstract

The response of a genotype each of C. molle and C. macrocarpum to drought (low soil moisture availability) was studied in a seasonally dry tropical environment throughout 3 consecutive years. Changes in soil water content, leaf water relations and gas exchange, chlorophyll fluorescence, forage yield and leaf area index (LAI) were compared in well-watered and droughted plots. Soil water depletion during the study occurred mostly at 0‒20 cm depth. Minimum values of leaf relative water content, water potential (ψl) and net photosynthesis in unwatered plants were within the ranges: 68 (C. molle) to 70% (C. macrocarpum); -1.6 (C. molle) to -0.9 MPa (C. macrocarpum); and 8 (C. molle) to 10 µmol/m2/s (C. macrocarpum), respectively. Leaf movements helped to avoid excessive solar radiation incidence, yet efficiency of chloroplast Photosystem II in stressed leaves of C. molle was negatively affected. Above-ground biomass and LAI were reduced only in C. macrocarpum (45‒50% reduction) as a result of moisture stress. Leaves of both species behaved as isohydric, though larger declines in ψl in C. molle may suggest a less effective control of water loss; this promoted more leaf senescence. Drought survival in these species depends on a combination of avoidance and tolerance strategies; the relative importance of both mechanisms depends on species and the duration and intensity of water deficit. Further studies with a higher number of accessions/ecotypes of each species are suggested in order to corroborate our findings.

 

Keywords: Acclimation, physiological response, soil transpirable water, tropical forage legumes, water stress.

Author Biography

Orlando Guenni, Universidad Central de Venezuela (UCV), Facultad de Agronomía (FAGRO), Maracay, Venezuela.

Orlando Guenni completed his undergraduate studies (Bachelor in Biology) at Simón Bolívar University, Venezuela in 1980 and a year later started his career in applied agricultural science as a research scientist at the National Institute of Agricultural Research (INIA, formerly FONAIAP). From 1982 to 1987 his research focused on forage plant (grasses and legumes) introduction and agronomic evaluation for animal production systems in savannah ecosystems. In 1992, he completed his PhD in Environmental Sciences at Griffith University, Queensland, Australia. After returning to Venezuela he continued working at INIA, evaluating ecophysiological aspects of grass-legume associations (drought resistance and N transfer) on acid savannah soils. In 1994, Orlando became Lecturer in Agricultural Ecology at the Agronomy Faculty of Universidad Central de Venezuela (UCV), Maracay. He led several research projects on the ecophysiology of tropical pastures, particularly on the effects of abiotic stresses (soil drought and shade) on growth, photosynthetic response and water relations of introduced grasses and legumes. From 2000 to 2007 he also led a multi-disciplinary research team in collecting and evaluating germplasm of native forage legumes for well-drained savannah environments in Venezuela. In 2008, he was appointed Associate Professor at UCV for undergraduate and graduate courses in Agricultural Ecology and Plant Ecology.

How to Cite

Guenni, O., Romero, E., Guédez, Y., Macías, M. P., & Infante, D. (2017). Survival strategies of <i>Centrosema molle</i> and <i>C. macrocarpum</i> in response to drought. Tropical Grasslands-Forrajes Tropicales, 5(1), 1–18. https://doi.org/10.17138/tgft(5)1-18

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Published

2017-01-30

Issue

Vol. 5 No. 1: January 2017

Section

Research Papers