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The significance of changes in the red/far‐red ratio, associated with either neighbour plants or twilight, for tillering in Lolium multiflorum Lam.
Author(s) -
CASAL J. J.,
SANCHEZ R.A.,
GIBSON DIANA
Publication year - 1990
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1990.tb00540.x
Subject(s) - lolium multiflorum , twilight , biology , phytochrome , far red , photoperiodism , shoot , competition (biology) , botany , dry weight , horticulture , agronomy , red light , ecology , physics , astronomy
SUMMARY Lolium multiflorum Lam. plants were used to investigate whether phytochrome‐mediated tillering responses, anticipatory to competition: (a), are potentially disturbed by the twilight drop in the red to far‐red ratio (R:FR) of sunlight (caused by atmospheric factors), and ( b ), occur in densely‐sown (> 280 plants m −2 ) grass canopies, where competition is quickly established. Isolated plants grown under sunlight received natural low R: FR during twilight, but supplementary R provided simultaneously did not increase tillering. When a wide range of R: FR was provided at the end of natural or fluorescent light photoperiods, tillering was reduced only by very low R: FR (lower than natural twilight R: FR). Leaf sheath length followed a similar pattern of response. Single plants were grown in pots placed at various densities. High densities reduced the R:FR at plant bases and the number of tillers per plant before changes in dry weight and leaf number were found. Both very low R:FR provided at the end of the photoperiod, and increasing plant densities, caused more erectophile shoots. In densely‐sown canopies of Lolium multiflorum both R:FR signals caused by neighbours, and tillering responses occur well before strong competition is established. Tillering is not obviously affected by the twilight drop in R: FR.