Abstract As in other cultivated species, dormancy can be seen as a problem cereal production, either due to its short duration or long persistence. Indeed, crops lacking enough at harvest exposed pre-harvest sprouting damage, while long-lasting interfere with processes that rely on rapid germination, such malting the emergence of uniform crop. Because ancestors species evolved under very diverse environments worldwide, different mechanisms have arisen way sensing an appropriate germination...

Light regulates dormancy termination and the subsequent germination in many weed species. Under field conditions, light environment of seeds, which is perceived mainly by photoreceptors phytochrome family, provides essential information for cueing proper environmental situation. The environment's spectral composition irradiance allow seeds to sense their position soil profile, presence a leaf canopy capturing other resources occurrence cultivation. From an agronomical point view, control...

Abstract Temperature is a key factor affecting both dormancy and germination. In non-dormant seeds, when temperature within the thermal range permissive for germination, it just regulates germination velocity, while in seeds presenting can also be level, termination expression of itself. This dual effect on often leads to misinterpretation obtained results confounds analysis effects seed populations some degree dormancy. present paper we discuss regulation level its implications expression,...

Two mechanisms have been suggested as being responsible for dormancy in barley grain: (i) ABA the embryo, and (ii) limitation of oxygen supply to embryo by fixation a result oxidation phenolic compounds glumellae. The aim present work was investigate whether hypoxia imposed glumellae interferes with metabolism thus resulting dormancy. In dormant non-dormant grains incubated at 20 °C 30 (i.e. when is not expressed), content decreased dramatically during first 5 h incubation before germination...

The precise adjustment of the timing dormancy release according to final grain usage is still a challenge for many cereal crops. Grain sorghum [Sorghum bicolor (L.) Moench] shows wide intraspecific variability in level and susceptibility pre-harvest sprouting (PHS). Both embryo sensitivity abscisic acid (ABA) gibberellin (GA) metabolism play an important role expression developing grain. In previous works, it was shown that, simultaneously with greater ABA higher SbABA-INSENSITIVE 4 (SbABI4)...

Summary Seeds integrate environmental cues that modulate their dormancy and germination. Although many mechanisms have been identified in laboratory experiments, contribution to germination dynamics existing communities involvement defining species habitats remain elusive. By coupling mathematical models with ecological data we investigated the of seed temperature responses three Nothofagus are sharply distributed across different altitudes Patagonian Andes. Seed responsiveness was linked...

The role of abscisic acid (ABA) and gibberellic (GA) in determining the dormancy level developing sorghum (Sorghum bicolor [L.] Moench.) seeds from varieties presenting contrasting preharvest sprouting behavior (Redland B2, susceptible; IS 9530, resistant) was investigated. Panicles both were sprayed soon after pollination with fluridone or paclobutrazol to inhibit ABA GA synthesis, respectively. Fluridone application panicles increased germinability Redland B2 immature caryopses, whereas...

Abstract 1. An early inhibition of germination in seeds Silene gallica and Brassica campestris which were continuously exposed to the light environment under an establishing wheat canopy, was observed two different experiments. Inhibition occurred c. 15 days after crop emergence, when canopy leaf area index (LAI) below one red (R):far‐red (FR) ratio recorded well above 0·8. 2. This inhibitory effect either overcome by filtering FR through a solution CuSO 4 or could be artificially imposed...

Abstract We studied changes in dormancy (as imposed by the different structures surrounding embryo, namely, endosperm, pericarp and glumellae) its relationship with embryonic ABA levels sensitivity, developing grains of two commercial barley cultivars: B 1215 Quilmes Palomar, which have, respectively, a low high level at harvest and, consequently, contrasting sprouting behaviour rainy years. Dormancy endosperm plus was gradually similarly alleviated throughout development both cultivars. The...

Abstract A model for simulating Polygonum aviculare L. seed dormancy loss in relation to stratification temperature was developed. The employs the lower limit germination ( T l ) as an index of population status. While mean l(50) and distribution within (σ Tl are allowed vary seeds released from dormancy, other thermal parameters characterizing responses (base, optimal maximal temperatures, time required germination) higher h held constant. In order relate changes σ variable temperature, a S...

At harvest, barley seeds are dormant because their germination is difficult above 20°C. Incubation of primary at 30°C, a temperature which they do not germinate, results in loss ability to germinate This phenomenon corresponds an induction secondary dormancy already observed after pre-treatment 30°C as short 4–6 h, and optimal 24–48 h. It associated with maintenance high level embryo ABA content during seed incubation transfer 20°C, while decreases rapidly embryos placed directly Induction...

Barley (Hordeum vulgare L.) seeds (grains) exhibit dormancy at maturity that is largely due to the presence of glumellae (hulls) reduce availability oxygen (O2) embryo. In addition, abscisic acid (ABA) and gibberellins (GAS) interact with O2 regulate barley seed dormancy. A population-based threshold model was applied quantify sensitivities excised embryos O2, ABA, GA, their interactive effects. The median requirement for germination dormant intact 400-fold greater than embryos, indicating...

Jatropha curcas is a drought-resistant tree whose seeds are good source of oil that can be used for producing biodiesel. A successful crop establishment depends on rapid and uniform germination the seed. In this work we aimed to characterize responses J. temperature water availability, using thermal time hydrotime analysis,Thermal analysis was performed data obtained from incubation at different temperatures potentials.Base optimum were 14·4 30 °C, respectively. Approximately 20 % seed...

Summary Grain sorghum ( Sorghum bicolor L. moench) stands as a globally significant cereal crop but the adversity of pre‐harvest sprouting (PHS) caused by reduced grain dormancy and moist conditions prior to harvest remains unsolved. Here, we identified QTL using Redlan×IS9530 RIL population, where parent lines are low in tannins early flowering otherwise contrasting plant height. We phenotyped this population 2 years with informative PHS‐related traits (grain germination index, embryo...

Pre-harvest sprouting is a major problem in Sorghum crops which leads to losses seed viability and produces important decreases grain weight. In this paper we aimed have an insight into the physiological basis of pre-harvest resistance crop by assessing germinability, ABA embryonic content sensitivity during development three varieties presenting contrasting behaviour: Redland B2 (very susceptible), SC 650 (moderately resistant) IS 9530 resistant). caryopses were able germinate with high...

• The effect of cold (stratification) temperature on changes in the sensitivity Polygonum aviculare seeds to light was investigated. Seeds buried pots were stored under stratification temperatures (1.6, 7 and 12°C) for 137 d. exhumed at regular intervals during storage exposed different treatments. Germination responses obtained treatments used develop a model predict light. Seed increased as dormancy loss progressed, showing successive acquisition low-fluence (LFR), very (VLFR), requirement...

Background and AimsPre-harvest sprouting susceptibility in grain sorghum (Sorghum bicolor) is related to low seed dormancy reduced embryo sensitivity inhibition of germination by abscisic acid (ABA). Intra-specific variability for pre-harvest might involve differential regulation ABA signalling genes.

Grain sorghum [Sorghum bicolor (L) moench] exhibits intraspecific variability for the rate of dormancy release and pre-harvest sprouting behavior.Two inbred lines with contrasting response were compared: IS9530 (resistant) RedlandB2 (susceptible).Precocious in is related to an early loss embryo sensitivity ABA higher levels gibberellins imbibed grains as compared IS9530.With aim identifying potential regulatory sites gibberellin metabolism involved expression immature both lines, we carried...