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Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Winter wheat sown in the spring does not manage to produce grains. Vernalization is necessary for wheat to pass from the vegetative phase to the generative phase. This happens in the same time with wheat "quenching". Studies show that vernalization can occur during germination, during plant growth or during seed formation and at the full maturity of the grains. Other research emphasizes that vernalization of wheat corresponds to the accumulation of total phytochrome in the vegetative apex and to the accumulation of this pigment in the leaves, and the phenomenon of quenching is achieved by a transformation of the total phytochrome in less sensitive forms to dehydration of cells produced by frost. Vernalization of cultivated wheat is mainly controlled by three loci of the VRN1 gene, VRN-A1, VRN-B1 and VRN-D1 located in the middle of the long arms of chromosomes 5A, 5B and 5D respectively. Spring wheat has alleles of the VRN1 gene that reduce or eliminate the vernalization requirement. As result of research there was identified a fourth gene that controls wheat vernalization requirement (VRN 4). They have shown that this gene is a transcribed copy of the VRN1 gene. The study of Kippes et al. (2015) highlights the importance of the VRN1 gene as a regulator of vernalization and as a major gene that controls adaptation strategies and the wheat life cycle. [ABSTRACT FROM AUTHOR]

Onions normally form bulbs in the first year of growth; however, exposure to low temperatures can induce flowering (vernalisation) before bulbs are produced. Based on the cultivation data of onions grown in Japan, we evaluated and validated a reported model describing the onion vernalisation response. The observed bolting rates of ‘Sapporoki’, which was used in the construction of a previous model, were a good fit to the model, whereas, the bolting rates of one of the overwinter-type cultivars, ‘Momiji No.3ʹ, were lower than the predicted value. The difference between the predicted and observed bolting rates in ‘Momiji No.3ʹ was caused by a larger VD0.5, the coefficient in vernalisation response models that represents the time point when half of the plants have bolted. Overwinter-type and/or bolting resistant cultivars can have parameters that indicate a further vernalisation requirement for bolting. The parameters in our model can be customised to the cultivar being investigated, and our study suggests the viability of modelling onion bolting by using air temperature. [ABSTRACT FROM AUTHOR]

The wheat florigen gene Wheat FLOWERING LOCUS T (WFT, which is identical to VRN3) is an integrator of the vernalization, photoperiod and autonomous pathways in wheat flowering. Many studies have indicated that VERNALIZATION 1 (VRN1) directly or indirectly up-regulates WFT expression in leaves. VRN1 encodes an APETALA1/FRUITFULL-like MADS box transcription factor that is up-regulated by vernalization and aging, leading to promotion of flowering. In this study, the VRN1 protein was expressed as a His-Tag fusion protein in Escherichia coli and used in an electrophoretic mobility shift assay (EMSA). The results from the EMSA indicated that the VRN1 protein directly binds to the CArG-box in the promoter region of WFT, suggesting the direct up-regulation of WFT by VRN1 in the leaves of wheat plants. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gene regulatory mechanisms are often defined in studies performed in the laboratory but are seldom validated for natural habitat conditions, i.e., in natura. Vernalization, the promotion of flowering by winter cold, is a prominent naturally occurring phenomenon, so far best characterized using artificial warm and cold treatments. The floral inhibitor FLOWERING LOCUS C (FLC) gene of Arabidopsis thaliana has been identified as the central regulator of vernalization. FLC shows an idiosyncratic pattern of histone modification at different stages of cold exposure, believed to regulate transcriptional responses of FLC. Chromatin modifications, including H3K4me3 and H3K27me3, are routinely quantified using chromatin immunoprecipitation (ChIP), standardized for laboratory samples. In this report, we modified a ChIP protocol to make it suitable for analysis of field samples. We first validated candidate normalization control genes at two stages of cold exposure in the laboratory and two seasons in the field, also taking into account nucleosome density. We further describe experimental conditions for performing sampling and sample preservation in the field and demonstrate that these conditions give robust results, comparable with those from laboratory samples. The ChIP protocol incorporating these modifications, "Field ChIP", was used to initiate in natura chromatin analysis of AhgFLC, an FLC orthologue in A. halleri, of which a natural population is already under investigation. Here, we report results on levels of H3K4me3 and H3K27me3 at three representative regions of AhgFLC in controlled cold and field samples, before and during cold exposure. We directly compared the results in the field with those from laboratory samples. These data revealed largely similar trends in histone modification dynamics between laboratory and field samples at AhgFLC, but also identified some possible differences. The Field ChIP method described here will facilitate comprehensive chromatin analysis of AhgFLC in the future to contribute to our understanding of gene regulation in fluctuating natural environments. [ABSTRACT FROM AUTHOR]

Epigenetic regulation is crucial for the development of plants and for adaptation to a changing environment. Recently, genome-wide profiles of histone modifications have been determined by a combination of chromatin immunoprecipitation (ChIP) and genomic tiling arrays (ChIP on chip) or ChIP and high-throughput sequencing (ChIP-seq) in species including Arabidopsis thaliana, rice and maize. Validation of ChIP analysis by PCR or qPCR using positive and negative regions of histone modification is necessary. In contrast, information about histone modifications is limited in Chinese cabbage, Brassica rapa. The aim of this study was to develop positive and negative control primer sets for H3K4me3 (trimethylation of the 4th lysine of H3), H3K9me2, H3K27me3 and H3K36me3 in B. rapa. The expression and histone modification of four FLC paralogs in B. rapa, before and after vernalization, were examined using the method developed here. After vernalization, expression of all four BrFLC genes was reduced, and accumulation of H3K27me3 was observed in three of them. As with A. thaliana, the vernalization response and stability of FLC repression correlated with the accumulation of H3K27me3. These results suggest that the epigenetic state during vernalization is important for high bolting resistance in B. rapa. The positive and negative control primer sets developed here revealed positive and negative histone modifications in B. rapa that can be used as a control for future studies. [ABSTRACT FROM AUTHOR]

In the last decades a new goal for agriculture is to develop environmentally friendly innovative technologies. One of the interest solutions, in perspective, is the treatment of plants with low power microwave irradiation in order to obtain a higher and healthier production. This approach could also contribute to mitigation of harmful effects produced by excessive use of chemical products in treatment of seeds and also field culture phytoprotection. Investigating effects of microwave irradiation, on the germination of common bean (Phaseolus vulgaris L. cv. Ardeleana) seeds, and on the growth and development of bean plantules, in specific experimental conditions. The trial was developed within Laboratories of the Advanced Research Centre for Environmental Protection and Assessment of Life Quality from USAMV Cluj-Napoca. The growing experiment of 10 - 8 days (with 49 individuals each) was developed until the seeds have grown up to 15 cm height, in conditions of microwave irradiated and no irradiated conditions. The studied parameters were: length of stems, length of roots, and seedling vigour index. Data were statistically processed with STATISTICA v 6.0 Office. The studied parameters were quantified by biometric approach (length of stems and roots). The use of low power microwave irradiation in germination of common bean in laboratory conditions may be taken into consideration for large scale cultivation. Further research is needed in order to establish appropriate practices for the success of this innovative technique. [ABSTRACT FROM AUTHOR]

The article discusses research which examines repression of the flowering locus C (FLC) clade members by Vascular plant one-zinc fingeri 1 (VOZ1) and VOZ2 to control flowering in Arabidopsis thaliana. Topics discussed include identification of VOZ1 and VOZ 2 as phytochrome B-interacting factors, role of VOZ1 and VOZ2 in downregulation of FLC, repressor of flowering, and suppression of phenotypes of the voz1 voz2 mutant by vernalization in the Columbia and FRIGIDA (FRI)-containing accessions.

Copyright of Listy Cukrovarnicke a Reparske is the property of VUC Praha a.s. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Scientiarum Polonorum. Agricultura is the property of University of Technology & Life Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming at the delayed sowing of winter wheat induced by the drought and water logging often occurred in Huanghuai Plains of China, six sowing dates (15 October, normal sowing; 30 October, moderate delay; 15 November, delay; 30 November, seriously delay; 15 February, early spring sowing; and 1 March, spring sowing) were designed to investigate the effects of different sowing dates on the shoot type morphology and growth characteristics of winter wheat. With the delay of sowing date, the winter wheat grew and developed faster, and the growing period of the wheat sown in early spring and spring was 115-130 days shorter than that with normal sowing. As compared with those of the wheat with normal sowing, the shoot height, spike number per unit area, and productive spikelets per unit ear of the wheat sown delayed had a decrease, leaf position and canopy moved down, and leaf area reduced. When the sowing was delayed from the date 15 October (normal sowing) to 1 March (spring sowing), the harvest index increased from 0. 46 to 0. 53. Delaying sowing date also resulted in the significant reduction of grain yield, with the maximum decrement as high as 43. 6%. The spring-sown winter wheat not going through vernalization could still form yield. [ABSTRACT FROM AUTHOR]

Abstract: In this review we have analysed two major biological systems involving epigenetic control of gene activity. In the first system we demonstrate the interplay between genetic and epigenetic controls over the transcriptional activity of FLC, a major repressor of flowering in Arabidopsis. FLC is down-regulated by low temperature treatment (vernalisation) releasing the repressor effect on flowering. We discuss the mechanisms of the reduced transcription and the memory of the vernalisation treatment through vegetative development. We also discuss the resetting of the repressed activity level of the FLC gene, following vernalisation, to the default high activity level and show it occurs during both male and female gametogenesis but with different timing in each. In the second part of the review discussed the complex multigenic system which is responsible for the patterns of gene activity which bring about hybrid vigour in crosses between genetically similar but epigenetically distinct parents. The epigenetic systems that we have identified as contributing to the heterotic phenotype are the 24nt siRNAs and their effects on RNA dependent DNA methylation (RdDM) at the target loci leading to changed expression levels. We conclude that it is likely that epigenetic controls are involved in expression systems in many aspects of plant development and plant function. [Copyright &y& Elsevier]

Abstract: This research was conducted to study the effect of three different sowing dates (15th October, 15th November and 15th December) and two vernalization treatments (5°C and −20°C) on leaf structure of Beta vulgaris L. cv. Univers. The obtained data are summarized as follows: The maximum values of the most studied parameters; lower epidermis+spongy tissue thickness, midrib, mesophyll tissue, vascular bundle, collenchymatous tissue and number of xylem vessels per arm were found as a result of 15th October sowing date treatment compared with the two other sowing dates. Furthermore, effect of the cooling treatments varied according to the recorded character, sowing date and cooling degree. Most of the vernalization treatments at early sowing dates increased the mesophyll tissue, midrib, number of vascular bundles per transverse section, vascular bundle thickness and number of xylem arms per transverse section. The two studied cooling treatments at 15th October sowing date increased both stomatal index and average number of stomata: average number of epidermis cells compared with the control. Furthermore, 15th October under −20°C treatment led to small epidermal cells and stomata formation, straight epidermal cell walls and closed stomata in comparison to the control. [Copyright &y& Elsevier]

Vernalization promotes flowering in winter wheat cultivars, whereas spring wheat cultivars are able to transition from vegetative to reproductive phase without vernalization. The wheat vernalization requirement is mainly controlled by the major locus Vrn-1, an APETALA1/FRUITFULL MADS-box gene homolog. To study natural variation of the vernalization requirement in a wild progenitor of common wheat, we sequenced the Vrn-Dt1 locus in four accessions of Aegilops tauschii Coss. Some structural mutations were found in the promoter and first intron regions of Vrn-Dt1, and haplotype analysis was conducted to examine the distribution of each identified mutation within 211 accessions of Ae. tauschiigermplasm. Out of the total, nine accessions, which were originally collected in Afghanistan and Pakistan, contained deletions of a 5.4-kb sequence in the critical region of the Vrn-Dt1 first intron. The 5.4-kb deletion mutation appeared independently of the dominant allele of the common wheat Vrn-D1 locus. The large deletion was absolutely associated with a lack of vernalization requirement for flowering under long-day conditions, but had no influence on heading date under field growth conditions. The levels of Vrn-1 and WFT transcript increased in the Ae. tauschii accessions having the large deletion. Identification of natural mutant accessions with a loss of vernalization requirement indicates the agricultural significance of Ae. tauschii as a genetic resource for wheat breeding. [ABSTRACT FROM AUTHOR]

Osmotic priming of cabbage seeds with polyethylene glycol (PEG 6000), to prevent germination during a vernalising treatment, was investigated as part of a study into potential seed production in the tropics. A preliminary attempt to vernalise cabbage seeds had resulted in weak stemmed seedlings, with fungal infections, as a consequence of the non- primed seeds having germinated while still in the fridge at the low temperatures used for vernalisation (0° – 5°C). Two experiments to determine the effect of PEG 6000 on the viability and vigour of cabbage seed at non-vernalisation and vernalisation temperatures were carried out. In the first experiment, seeds of ten varieties of cabbage were imbibed separately in 302.44 g l-1 PEG 6000 in Petri dishes lined with filter papers moistened with PEG solution, or with distilled water as controls. The primed seeds were kept for 2 weeks at 25°C (non-vernalisation temperature) under an 8 h photoperiod, washed in distilled water and sown immediately into 4 cm-square plastic modular trays filled with Levington F2S compost. Priming did not have any significant effect on the proportion of seeds that germinated (P>0.05), but significantly enhanced the coefficient of velocity (CV) at 25°C. In the second experiment, seeds of four varieties of cabbage were primed at 0° – 5°C for 8 weeks prior to sowing in compost. Controls were seeds primed in the same concentration of PEG 6000 and kept at 25°C for 11 d, and seeds sown without priming or vernalisation. Again, priming of cabbage seed with PEG 6000 had no adverse effect on the proportion of seeds that germinated, but promoted the CV (vigour) of seeds kept at vernalisation temperatures (0° – 5°C). [ABSTRACT FROM AUTHOR]

In an attempt to produce seeds from shallots, vernalisation of growing plants was effective. However, young plants failed to flower before they attained a critical stage of development. To identify the stage of development at which plants bolt satisfactorily, 20 plants of each of three shallot varieties: one long-day (LD) cv. ‘Matador F1’, and two short-day (SD) cvs., ‘Tropix’ and ‘Rox F1’, were grown in two separate greenhouses maintained at approx. 18°C with 16 h or 12 h photoperiods, respectively, for periods of 120, 90, 60, 30 or 0 d (imbibed seeds). Seedlings and imbibed seeds were then vernalised in growth chambers at 8°C for 60 d. Logistic regression was used to predict the probability of bolting plants, and plant-to-plant variation was used to analyse the other data. Complete bolting was obtained in plants vernalised after attaining about the six-leaf stage (after 90 d) in cv. ‘Tropix’, the 17 leaf-stage (120 d) in cv. ‘Rox F1’ and the 12 leaf-stage (120 d) in cv. ‘Matador F1’. The corresponding total soluble carbohydrate (TSCHO) levels [in g 100 g-1 sheath dry weight (DW)] were 7.8, 9.8 and 15.5, respectively. However, the percentages of bolting after 90 d of growth for cvs. ‘Rox F1’ and ‘Matador F1’ were 75% and 60%, respectively. Apart from their high percentage of bolting, plants which attained sufficient size also induced floral shoots and bolted shortly after the end of vernalisation. An increase of one inflorescence per plant was obtained as the time before treatment was increased from 90 to 120 d in the two SD cultivars. In addition, plants of the three cultivars vernalised after 120 d produced, on average, approx. 4.4, 1.38 and 0.52 inflorescences d-1 per treatment (20 plants), whereas those vernalised after 90 d or 60 d produced approx, one inflorescence d-1, and one-to-two inflorescences 10 d-1, respectively. A strong positive correlation was also observed between TSCHO content and the percentage of bolting. This study showed that vernalising shallot seedlings at 60 d, or younger, does not result in sufficient bolting. [ABSTRACT FROM AUTHOR]

A series of three experiments was conducted to determine the effects of temperature and lighting on bud initiation and flower expression in lavender. A period of nine weeks at 4°C was shown to satisfy the vernalization requirement for all plants, and after five weeks at 4°C, 50% of plants flowered. Vernalization was shown to occur more slowly at temperatures above 4°C and was observed up to 16°C. Following vernalization, a higher temperature advanced bud appearance, with an optimum temperature of 20°C, but reduced the number of buds. When vernalization was incomplete, a higher temperature delayed bud appearance and reduced the number of buds. A daylength of 15 h compared with 8 h either during or after cold treatment increased the number of buds produced, suggesting that additional lighting may be needed for the winter production of plants in flower. Whilst it was possible to model flower development after bud appearance, unexplained variation between experiments in the time to first visible bud prevented satisfactory mathematical description of floral bud production. It was concluded that the "environmental history" of commercially micro-propagated material had a significant effect on the duration of cold required for vernalization, and that differences in the vernalization requirement of individual meristems led to variation in the cold requirements of plants within a crop. The commercial significance of these conclusions is discussed. [ABSTRACT FROM AUTHOR]

Models to simulate the induction of the "bracting" and "riciness" defects in cauliflower were estimated from field experiments. Bracting, where small cauline leaves develop and penetrate the curd surface, is caused by high temperatures — a kind of de-vernalization. Riciness, on the other hand, where small flower buds develop on the curd surface, is caused by low temperatures, especially after a preceding period of high temperature — a kind of strong vernalization. Both bracting and riciness can be induced only at certain stages during plant development. Plots of cauliflower were given periods of different temperature treatments in the field by portable compartments with both cooling and heating units. The treatments were both constant high or low temperatures (24, 18, 13 and 8°C) in 10 d periods, and alternating high and low temperatures (23/23, 23/15, 23/10 and 23/5°C) in 7 d periods. The treatments were started both before and after curd induction. The incidences of bracting and riciness in harvested curds were recorded in 84 plots with different temperature regimes. These data were used to estimate the combined effect of plant development and temperature on quality defects. The responsive developmental stages in the plants were described by a parabolic function, which depends on the apex/curd diameter. The curd diameter with the highest risk of induction of bracting was estimated to be around 12 mm (range 1-23 mm). A combined model of the diameter function and the summation of daily average temperature with a base temperature of 15°C explained 66% of the variation in the data of observed bracting. The apex diameter with the highest risk of induction of riciness was estimated to be around 0.35 mm (range 0.2-0.5 mm). A combined model of sensitive apex diameter and the preceding temperatures (average daily temperature of 10 d), during a temperature drop (average minimum temperature of 10 d), and after (average daily temperature of 6 d) explained 71% of the variation in the data of observed riciness. These models may be used to set up test equipment and to test susceptibility of new cultivars in breeding programmes. On a farm level, the models may be used to forecast risk of quality defects in cauliflower production. Alternatively, the knowledge of how the combination of developmental stage and temperature scenario induce either bracting or riciness may be used to study flower induction by temperature. [ABSTRACT FROM AUTHOR]