TITLE:
Chlorophyll Fluorescence as an Indicator of Cellular Damage by Glyphosate Herbicide in Raphanus sativus L. Plants
AUTHORS:
Fábia Barbosa Silva, Alan Carlos Costa, Rodolfo Rodrigo Pereira Alves, Clarice Aparecida Megguer
KEYWORDS:
Pigments Chloroplastidic, EPSPS, Chlorophyll, Fluorescence
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.16,
July
31,
2014
ABSTRACT: The fodder radish is an important alternative late summer crop in central-western
Brazil. The fodder radish has a short growing cycle, is highly productive and possesses
qualities that enhance its cultivation potential as an alternative in Brazil’s Biodiesel
Program. However, drift of herbicides, such as glyphosate, may hinder the development
of fodder radishes. Studies of chlorophyll fluorescence can provide measurements
that help assess the effect of herbicide, being good indicator of the damage to
photosynthetic apparatus promoted by herbicide. This study was carried out to analyze the effects of glyphosate by measuring chlorophyll a fluorescence, cellular membrane stability and chloroplast pigment contents in fodder radish plants. This experiment used a randomized block design in which
the treatments consisted of the following 6 different doses: control, 0, 150, 300,
450, 600, 750 and 900 g i.a. ha-1 of the recommended 480 g·L-1 dose of glyphosate acid equivalent. The plants were
sprayed 30 days after emergence and were assessed every 48 hours. The characteristics
evaluated, including chlorophyll a fluorescence, chloroplast pigments and the rate of electrolyte leakage, indicated that radish
plants are sensitive to glyphosate because the treatments resulted in reduced levels
of photosynthetic efficiency and increased damage to cellular membranes, which
led to a reduction in the chloroplast pigment content.