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The effect of atrazine, cyanazine and cyprazine on photosynthesis and growth of nine grasses *
Author(s) -
JENSEN K. I. N.,
STEPHENSON G. R.,
HUNT L. A.,
BANDEEN J. D.
Publication year - 1977
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1977.tb00497.x
Subject(s) - atrazine , panicum miliaceum , phytopharmacology , digitaria sanguinalis , agronomy , panicum , phytotoxicity , photosynthesis , triazine , biology , poaceae , chemistry , weed , horticulture , botany , pesticide , polymer chemistry
Summary: A semi‐open circuit system for measuring changes in net CO 2 exchange (NCE) in single leaves of intact grasses following herbicide treatment is described and evaluated. There were significant differences in levels of inhibition and subsequent recovery of NCE in maize and eight weedy panicoid grasses following limited root uptake of atrazine (2‐chloro‐4‐ethyl‐amino‐6‐isopropylamino‐1,3,5‐triazine). cyanazine [2‐chloro‐4‐(1‐cyano‐1‐methylethylamino)‐6‐ethylamino‐1,3,5‐triazine] and cyprazine (2‐chloro‐4‐cyclopropylamino‐6‐isopropyl‐amino‐1,3.5‐triazine). Rate of NCE recovery was positively correlated (P = 0.05) with growth of seedlings in nutrient solution containing the herbicides. Rates of NCE recovery >0.9 mg CO2 per dm2 per h/h reflected rapid rates of herbicide detoxification in the leaves and a significant tolerance to preplant incorporated and postemergence applications of atra‐zine, cyanazine and cyprazine. In contrast, some species, e.g. large crabgrass [Digitaria sanguinalis (L.) Scop.] and proso millet ( Panicum miliaceum L.) treated with cyanazine demonstrated considerable tolerance to these treatments in spite of low NCE recovery rates indicating that factors other than foliar detoxification may play an important role in the tolerance of some grasses to 2‐chloro‐ 1,3,5‐triazine herbicides.