Studies on the flowering biology of red sorrel (Rumex acetosella) ramets from lowbush blueberry (Vaccinium angustifolium) fields in Nova Scotia, Canada

Abstract

Red sorrel (Rumex acetosella L.) is a ramet-producing herbaceous creeping perennial species commonly found as a weed in commercially managed lowbush blueberry (Vaccinium angustifolium Aiton) fields in Nova Scotia, Canada. Flowering and seed production occur primarily in overwintering ramets of this species, indicating a potential vernalization requirement for flowering. This study was therefore initiated to examine the role of vernalization, photoperiod, and pre-vernalization stimulus on ramet flowering. Red sorrel ramets propagated from creeping roots and seeds collected from established red sorrel populations in lowbush blueberry had an obligate requirement for vernalization to flower. Ramet populations maintained under pre- and post-vernalization photoperiods of 16 h flowered following 12 weeks of vernalization at 4 ± 0.1 °C, whereas those maintained under constant 16, 14, or 8 h photoperiods without vernalization did not flower. Vernalization for 10 weeks maximized, but did not saturate, the flowering response. Pre-vernalization photoperiod affected flowering response, with increased flowering frequency observed in ramet populations exposed to decreasing, rather than constant, photoperiod prior to vernalization. This study represents the first attempt to determine the combined effects of vernalization and photoperiod on red sorrel flowering, and the results provide a benchmark for the future study of flowering and sexual reproduction in this economically important perennial weed species.

Seed production in grassland species: Morpho‐biological determinants in a species‐rich semi‐natural grassland

“…Flowering only during the second growth period was probably due to the plants needing high temperatures for floral induction. Flowering only during the first growth period was probably a consequence of the plant death after fruit maturation or dual‐induction requirements for some forbs, such as in Rumex acetosa , whose congeneric R. acetosella has an obligate vernalization requirement (White, Boyd, Van Acker, & Swantonc, ).…”

Weed Survey of Nova Scotia Lowbush Blueberry (Vaccinium AngustifoliumAit.) Fields

“…Seedlings emerge throughout the growing season (White et al, 2014), but vegetative reproduction of ramets from the creeping root system is the primary means of population growth (Kennedy, 2009;White et al, 2014). Ramets emerge throughout the growing season in Nova Scotia (White et al, 2014(White et al, , 2015a and emerged ramets remain as vegetative rosettes below the blueberry canopy due to a vernalization requirement for flowering (White et al, 2014(White et al, , 2015b. This growth pattern facilitates prolonged periods of indeterminate vegetative growth in this weed species which, when coupled with lack of adequate control from herbicides, seed spread on machinery, documented increases in lowbush blueberry growing season length (Drummond and Yarborough, 2014), and increased vegetative growth of red sorrel following fertilization (Kennedy et al, 2011), likely accounts for the large increase in field uniformity and density that have occurred since 2000-2001.…”

Pre- and post-vernalization ramet removal reduces flowering of red sorrel (Rumex acetosellaL.) in wild blueberry (Vaccinium angustifoliumAit.)

“…These results provide an important baseline for assessing flowering in future research, and suggest a low probability of flowering in young ramets re-establishing after pre-vernalization control measures. Ramets also appear to require exposure to long days prior to vernalization for flowering to occur (White et al 2015). Ramets emerging under short days following pre-vernalization control measures, as occurred in the pre-vernalization clipping treatment, may therefore have photoperiodic restrictions on flowering regardless of exposure to vernalizing temperatures.…”

“…Seedlings contribute to established red sorrel populations in wild blueberry fields ), but vegetative reproduction of ramets from the creeping root system is the primary means of population maintenance (Kennedy 2009;White et al 2014). The majority of red sorrel ramets remain as vegetative rosettes persisting below the blueberry canopy in the year of emergence, as flowering occurs primarily in overwintering ramets and is induced by vernalization and subsequent exposure to long days (White et al 2015). Flowering ramets bolt and grow taller than established blueberry stems, hindering harvest operations in heavily infested fields.…”