Abstract

CAMBRON-SANDOVAL, Víctor Hugo et al. Chlorophyll production in Pinus pseudostrobus juveniles under different development environments. Rev. Chapingo ser. cienc. for. ambient [online]. 2011, vol.17, n.2, pp.253-260. ISSN 2007-4018.  https://doi.org/10.5154/r.rchscfa.2010.09.077.

Limiting the amount of sun radiation reduces photosynthetic activity, causing stress and morphological and/or physiological changes in plant development. This study analyzed the stress effect caused by two levels of competition in Pinus pseudostrobus Lindl half-sib families: high inter-family (environment II) and high intra-family (environment III) competition, compared with a low level of competition (environment I). Total chlorophyll, chlorophyll-a, and chlorophyll-b content, plus the chlorophyll a/b ratio, were quantified as an indicator of stress level in 10-month-old plants using the Barnes method. Plants were established in a common garden test under a split-plot design with four replications and three individuals per plot. Total chlorophyll was significantly higher (P<0.05) in environment I; no differences (P>0.05) were observed between the other competition environments. A separate analysis of chlorophylls showed lower chlorophyll-a content in plants surrounded by genetically-similar plants (environment III) as opposed to genetically-different ones (environment II); conversely, chlorophyll-b content was higher in genetically-similar plants (environment III). In conclusion, intra-genotypic competition was generally stronger than inter-genotypic competition, under high levels of stress.

Keywords : Half-sib families; total chlorophyll; a chlorophyll; b chlorophyll; a/b chlorophyll; competition environment.