Reduction of Ryegrass (Lolium multiflorum Lam.) Natural Re-Sowing with Herbicides and Plant Growth Regulators

Ryegrass (Lolium multiflorum Lam.) is the main winter weed of crops in Southern Brazil. High competitiveness, adaptability, widespread resistance to herbicides and seed dormancy make the plant a permanent problem. Herbicides, as well as plant growth regulators, can be used as a management option for ryegrass seed production, however there is no consensus among authors at which stage of the plant the application is most effective. Thus, this study aimed to evaluate the production and physiological quality of ryegrass seeds in response to the application of herbicides and plant growth regulators in three stages of plant development (inflorescence emergence, flowering and fruit development). Each treatment consisted of applying two different doses of each of the active ingredients: ammonium glufosinate, clethodim, glyphosate, iodosulfuron-methyl, paraquat and 2,4-D (herbicides); ethephon and trinexapac-ethyl (plant growth regulators), still an untreated control, totaling 17 treatments for each stage of development. The experimental design used was randomized blocks, with three replications. The variables evaluated were: seed production (kg ha−1), thousand seed weight (g), viability (%), germination (%), first germination count (%), dormant seeds (%) and dead seeds (%). The ryegrass seed production reduced 100% with clethodim, glyphosate, ammonium glufosinate or paraquat applied in the inflorescence emergence or flowering stages. In the fruit development stage, all treatments (herbicides and plant growth regulators) caused deleterious effects on seed production, the greatest effect occurred with paraquat (95%). Paraquat, ammonium glufosinate and clethodim affected the physiological quality of the seeds when applied in fruit development stage. This research demonstrated that the application of herbicides in the ryegrass reproductive stage decreases its seedbank replenishment (natural re-sowing), with the potential to harm its progeny.

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Foliar application of plant growth regulators changes the physiological quality of crambe seeds

Acta Scientiarum Biological Sciences ◽

10.4025/actascibiolsci.v41i1.46093 ◽

2019 ◽

Vol 41 ◽

pp. e46093 ◽

Cited By ~ 1

Author(s):

Nayara Parisoto Boiago ◽

Silvia Renata Machado Coelho ◽

Giovana Scalcon Fernandes ◽

Carlos Henrique de Oliveira Paz ◽

Felipe Samways Santos

Keyword(s):

Electrical Conductivity ◽

Plant Growth ◽

Plant Growth Regulators ◽

Growth Regulators ◽

Germination Percentage ◽

Control Treatment ◽

Cultivated Plants ◽

Germination Speed ◽

Physiological Quality

The application of plant growth regulators can manipulate the development of cultivated plants, and their physiological effects may be reflected in the physiological quality of the seeds. This study evaluated the effects of plant growth regulators (PGR) on the physiological quality of crambe seeds produced in the 2014 and 2015 harvests. During crop development, we applied two foliar sprayings of the following treatments: 1) control treatment with distilled water; 2) indole-3-acetic acid 100 mg L-1 (IAA); 3) 3-gibberellic acid P.A. 100 mg L-1 (GA3); 4) commercial PGR Stimulate® 6 mL L-1. The seeds were harvested and evaluated for water content, germination percentage and germination speed index (GSI), electrical conductivity and concentrations of leached Ca, Mg and K ions. Means were compared by Tukey´s and Dunnett tests (p<0.05). Applying Stimulate® increased the germination percentage and the germination speed index, while IAA application showed an opposite effect, increasing the electrical conductivity of crambe seeds. Calcium leaching decreased with IAA application, and all regulators reduced K leaching. We therefore infer that the application of plant growth regulators influences the physiological quality of crambe seeds.

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Somatic Embryogenesis and Plant Development in Eight Cultivars of Pecan

HortScience ◽

10.21273/hortsci.25.5.573 ◽

1990 ◽

Vol 25 (5) ◽

pp. 573-576 ◽

Cited By ~ 7

Author(s):

I.E. Yates ◽

C.C. Reilly

Keyword(s):

Somatic Embryogenesis ◽

Plant Growth ◽

Plant Growth Regulators ◽

Growth Regulators ◽

Plant Development ◽

Fruit Development ◽

Somatic Embryos ◽

Carya Illinoensis ◽

Appreciable Variation

The influence of stage of fruit development and plant growth regulators on somatic embryogenesis and the relation of cultivar response on somatic embryogenesis and subsequent plant development have been investigated in eight cultivars of pecan [Carya illinoensis (Wangenh.) C. Koch]. Explants from the micropylar region of the ovule were more embryogenic when removed from fruits in the liquid endosperm stage than were intact ovules from less-mature fruits or from cotyledonary segments of more-mature fruits. Explants conditioned on medium containing auxin alone or auxin + cytokinin produced more somatic embryos than medium containing cytokinin alone. Under the conditions of this study, frequency of embryogenesis, as well as the germination of somatic embryos leading to plant development, indicated appreciable variation among cultivars. Plant development was greatest by far from somatic embryos of `Schley' than other cultivars studied.

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