J Plant Ecol ›› 2014, Vol. 7 ›› Issue (1): 77-85.DOI: 10.1093/jpe/rtt017

• Research Articles • Previous Articles     Next Articles

Resource manipulation reveals flexible allocation rules to growth and reproduction in a Mediterranean evergreen oak

Fernando Pulido1,*, Gerardo Moreno1, Eustolia García2, José J. Obrador2, Raúl Bonal3 and Mario Díaz4   

  1. 1 Grupo de Investigación Forestal, Ingeniería Forestal y del Medio Natural, Universidad de Extremadura, E-10600 Plasencia, Cáceres, Spain; 2 Colegio de Postgraduados, Campus Tabasco, MX-86500 Cárdenas, Tabasco, Mexico; 3 Instituto de Investigación en Recursos Cinegéticos, (CSIC-UCLM-JCCM), University of Castilla-La Mancha, Ciudad Real, Spain; 4 Department of Biogeography and Global Change (BCG-MNCN), Museo Nacional de Ciencias Naturales, CSIC, E-28006 Madrid, Spain
  • Received:2012-12-18 Accepted:2013-03-09 Published:2014-01-24
  • Contact: Pulido, Fernando

Abstract: Aims In plants, resource allocation to growth and reproduction may depart from trade-off expectations if (i) investment in growth and reproduction relies on different resource pools, (ii) allocation to reproduction is dependent upon reaching some growth threshold or (iii) reproduction is developmentally linked to growth, both functions relying on the same resource pool. We examined the effects of enhanced resource level on patterns of resource allocation to growth and reproduction in holm oak (Quercus ilex sbsp. ballota), a Mediterranean evergreen tree.
Methods In the experimental year (2003), we manipulated the amount of soil nutrients in autumn (to increase nutrient uptake during shoot elongation in the following spring) and soil water in summer (to increase water uptake during acorn growth). Indicators of growth and male and female reproduction were estimated in the pre-experimental (2002), experimental (2003) and post-experimental (2004) years.
Important findings Fertilized trees produced significantly longer shoots, but the number of female flowers per shoot was not affected by treatments. The production of male catkins was also enhanced by fertilization. Irrigation did not affect the production of female flowers or abortion rates. Growth and female reproduction showed no consistent relationship in untreated trees, but resource addition elicited a growth-female reproduction trade-off in the experimental year. The sign of this significant relationship changed in the post-experimental year, indicating the existence of lagged effects of resource manipulation on acorn production. Overall, patterns of allocation to growth and reproduction varied as a function of sex, resource availability and year, a result consistent with extreme allocational plasticity in holm oak.

Key words: acorn abortion, allocational plasticity, dehesa, growth-reproduction trade-offs, nutrient addition, Quercus ilex, resource allocation

摘要:
Aims In plants, resource allocation to growth and reproduction may depart from trade-off expectations if (i) investment in growth and reproduction relies on different resource pools, (ii) allocation to reproduction is dependent upon reaching some growth threshold or (iii) reproduction is developmentally linked to growth, both functions relying on the same resource pool. We examined the effects of enhanced resource level on patterns of resource allocation to growth and reproduction in holm oak (Quercus ilex sbsp. ballota), a Mediterranean evergreen tree.
Methods In the experimental year (2003), we manipulated the amount of soil nutrients in autumn (to increase nutrient uptake during shoot elongation in the following spring) and soil water in summer (to increase water uptake during acorn growth). Indicators of growth and male and female reproduction were estimated in the pre-experimental (2002), experimental (2003) and post-experimental (2004) years.
Important findings Fertilized trees produced significantly longer shoots, but the number of female flowers per shoot was not affected by treatments. The production of male catkins was also enhanced by fertilization. Irrigation did not affect the production of female flowers or abortion rates. Growth and female reproduction showed no consistent relationship in untreated trees, but resource addition elicited a growth-female reproduction trade-off in the experimental year. The sign of this significant relationship changed in the post-experimental year, indicating the existence of lagged effects of resource manipulation on acorn production. Overall, patterns of allocation to growth and reproduction varied as a function of sex, resource availability and year, a result consistent with extreme allocational plasticity in holm oak.