Cyanamide Research Articles

Hydrogen cyanamide levels and mineral oil for budbreak induction of ‘Baigent’ apple trees under anti-hail net in southern Brazil

Hydrogen cyanamide levels and mineral oil for budbreak induction of ‘Baigent’ apple trees under anti-hail net in southern Brazil

Response of “White Robin” Peach Trees Cv. (Prunus persica L.) to Cultivation Under Plastic Covering Conditions and Foliar Application by Hydrogen Cyanamide and Garlic Extract

A field experiment was carried out during 2018 and 2019 seasons on 4 years old ‘White Robin’ peach trees cv. (Prunus persica L.), to investigate the effect of cultivation peach trees under plastic covering conditions (PC) with combination of hydrogen cyanamide (HC at 0.5%) as a Dormex and garlic extract (GE at 1%) on floral and vegetative bud break time, vegetative growth parameters, fruit set, yield and fruit quality of this cultivar. Eight treatments, HC alone, GE alone, HC + GE, PC alone, PC + HC, PC + GE, PC + HC + GE and control were applied. The application of HC and GE under PC, resulted in earlier buds break and harvesting period by 10 and 20 days, respectively. Moreover, it shortened the period between both of flower and vegetative buds break and onset to end fruit harvesting by 10 days. It significantly increased shoot length, diameter and leaf area compared to control and other treatments. Furthermore, it improved fruit physical and chemical properties beside increasing the yield by 30%. All studied parameters gradually improved by other investigated treatments as follow: PC + HC, PC + GE, PC alone, HC and GE, HC alone then GE alone compared by control. Plastic covering might be useful for early peach cultivars for advancing fruit maturity and improving yield and fruit quality, that will be more suitable for exportation and profitable for growers under conditions of Egypt.

Hydrogen cyanamide induces grape bud endodormancy release through carbohydrate metabolism and plant hormone signaling

BackgroundGrape buds exhibit non-uniform, or delayed, break in early spring in subtropical regions because the accumulation of chilling is insufficient. Hydrogen cyanamide (H2CN2, HC) can partially replace chilling to effectively promote bud sprouting and is used widely in warm winter areas. However, the exact underlying mechanism of grape bud release from endodormancy induced by HC remains elusive.ResultsIn this study, the transcriptome of grape winter buds under in vitro conditions following HC and water treatment (control) was analyzed using RNA-seq technology. A total of 6772 differentially expressed genes (DEGs) were identified. Furthermore, the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that starch and sucrose metabolism and plant hormone signaling transduction were most enriched out of the 50 total pathways. HC treatment induced the upregulated expression of sucrose synthase (SUS), sucrose phosphate synthase (SPS), α-amylase (AM), and β-amylase (BM) and downregulated expression of sucrose invertase (INV), hexokinase (HK), fructokinase (FK), soluble starch synthase (SS), and granule-bound starch synthase (GBSS). Hence, the starch concentration in the HC-treated group was significantly lower than that in control, whereas soluble sugar content in the HC-treated group increased quickly and was higher than that in control between 0 and 8 d. The concentration of indoleacetic acid (IAA) and zeatin (ZT) increased, whereas that of abscisic acid (ABA) and gibberellin (GA) decreased in HC treated group, which coincided with the expression level of genes involved in above hormone signals. The content of hydrogen peroxide (H2O2) and enzyme activity of superoxide dismutase (SOD) and peroxidase (POD) were increased in grape buds with HC treatment, whereas catalase (CAT) activity was decreased. HC treatment increased the expression of POD, SOD, primary amine oxidase (PAO), polyamine oxidase (PAOX), and glutathione peroxidase (GSH-Px).ConclusionBased on these results, it is possible to propose a mechanistic model that underlies the regulation of endodormancy release in grapevine buds by exogenous HC application.

Buds of “Italia melhorada” grapevines grown under tropical conditions develop a quiescent state

A double cropping system for the grapevine (Vitis vinifera L) has been commercially adopted for use in regions where the tropical climate is characterized by high temperatures and small variations in daylength throughout the year. Under these climatic conditions, the use of hydrogen cyanamide (HC), a compound that breaks bud dormancy, is mandatory to produce homogeneous budbreak. However, it is unknown whether grapevine buds are capable of developing endodormancy (ED) under these climatic conditions. In this study, typical signals of ED, such as the number of nodes per cane, the development of periderm and the thickening of the cell wall of the bud meristematic cells, were analysed in vines of “Italia melhorada” grown in Mossoró, Brazil (5°12′16″S), under a natural (ND) photoperiod (12/12 h), a short-day (SD) photoperiod (10/14 h) and a long-day (LD) photoperiod (14/10 h). The abundance of phytochrome A (VvPHYA) and B (VvPHYB) and FLOWERING LOCUS T (VvFT) transcripts in the leaves and buds was also determined. The results showed a reduced number of nodes per cane and development of the periderm in the shoots of grapevines grown under ND and SD photoperiods. In addition, compared with that under the LD photoperiod, the expression of VvPHYA and VvFT under the ND and SD-photoperiod decreased, and the expression of VvPHYB increased. However, the thickness of the cell wall of the bud meristematic cells increased only in the grapevines exposed to the SD photoperiod. Therefore, we hypothesize that cell wall thickening is a characteristic of ED, while decreased expression of VvPHYA and VvFT and increased expression of VvPHYB are characteristic of quiescence. Consequently, under a tropical conditions, the grapevine buds would be in a quiescent state and not in a dormant state.

Effect of a Late Spring Application of Hydrogen Cyanamide on High-Chill Peaches

Due to a record low chilling accumulation in the winter of 2016–2017, many high-chill peach cultivars displayed almost no budbreak by mid-April of 2017 in central Georgia, USA, where budbreak usually occurs around mid-March. In this study, nine of these peach cultivars were used to study the effect of a late spring Dormex spray application (April 13, 2017) on subsequent budbreak, year-end cumulative vegetative growth, and following-season yield. Dormex was found to have strong stimulating effects on lateral budbreak, but little effect on terminal and floral budbreak. It also had apparent phytotoxic effects on lateral, terminal and floral buds, and growth. The effects varied among genotypes, tree ages, and shoot types. The peak of the effects occurred two weeks post-application. Most floral buds abscised before they swelled. Between Dormex-sprayed trees and unsprayed controls, there was no significant difference in the number and average length of the new lateral shoots by the end of 2017, nor in the number and weight of the fruit harvested in 2018. In conclusion, our data showed a late spring Dormex spray application stimulated earlier lateral budbreak and caused some level of phytotoxicity to all types of buds and new growth, but had little impact on flower budbreak, fruit set, year-end vegetative growth, or following-season yield. These findings provide useful information for growers, considering the need for spraying dormancy-breaking compounds when faced with insufficient chilling.

EU court tosses challenges to regulations

The European Union General Court hasrejected separate legal challenges to regulation of the plastics chemical bisphenol A (BPA) and of the solvent 1-bromopropane. The court dismissed both cases Sept. 20. In one suit, PlasticsEurope, an association of manufacturers, challenged the European Chemicals Agency (ECHA) description in 2017 of BPA, an estrogenic chemical, as “a substance with endocrine disrupting properties that may have serious effects on human health.” ECHA added BPA to its list of substances of very high concern in 2017. Chemicals on the list are candidates for strict control under the EU’s Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) law. In the second suit, chemical maker ICL challenged a 2017 regulation restricting 1-bromopropane, also known as n-propyl bromide, without any exemptions for specific uses. The court rebuffed industry arguments in both cases. In a related development, ECHA is proposing to restrict the use of calcium cyanamide as a

Residue Dynamics of Hydrogen Cyanamide and Ethephon in Apple

Residue Dynamics of Hydrogen Cyanamide and Ethephon in Apple

Soil Solarization and Calcium Cyanamide Affect Plant Vigor, Yield, Nutritional Traits, and Nutraceutical Compounds of Strawberry Grown in a Protected Cultivation System

Soil solarization is a hydrothermal procedure of disinfesting soil of soilborne diseases and pests. Solarization can be combined with many other chemical or non-chemical alternatives to afford integrated pest and diseases management or improve plant yield. Calcium cyanamide (CaCN2) is a fertilizer used in agriculture sector and is also effective in suppressing soilborne pathogens. The present study assessed the influences of different pre-plant CaCN2 dosages on strawberry grown on solarized or non-solarized soil. Soil solarization and 500 kg ha−1 CaCN2 significantly increased early marketable yield by 105.3%, total marketable yield by 53.0% and firmness by 3.0%, respectively compared with the control (no solarization × 0 kg ha−1 of CaCN2). Exposing solarized plots to CaCN2 at 1000 kg ha−1 significantly increased fruit ascorbic acid content by 77.5% and phenolic content by 13.3% compared with fruits from control plants. Overall, plants grown on solarized soil performed better than those cultivated on no-solarized plots. Plants grown on soil treated with a dosage of 500 or 1000 kg ha−1 CaCN2 increased plant height, number of shoots plant−1, number of leaves plant−1, root collar diameter, plant visual quality, anthocyanins, and antioxidant capacity compared to control plants. Fruits from plants grown on soil exposed to CaCN2 with a dosage of 500 and 1000 kg ha−1 showed a lower N fruit content (5.4 and 19.5%, respectively) than control plants (non-treated control).

Pruning and dormancy breaking make two sustainable grape-cropping productions in a protected environment possible without overlap in a single year.

In table grape production, protected cultivation in a vineyard in different regions and climates is currently a commonly used practice. The aims of this study were to provide key approaches to sustainably produce two crops of grape without overlap under protected environment in a single year. Spraying the degreening chemicals 400 mg/L ethephon +0.4% sulfur at 4 weeks of vine nutrient restoration after the harvest of the summer crop resulted in the highest percentage of sprouting inflorescence. The retention of 7–10 buds in the base shoot results in the high percentage of sprouting inflorescence. Bud breaking chemicals with 2.5% hydrogen cyanamide+2.0% Baoguoliang +0.02% Shenzhonggen significantly led to sprout inflorescence more efficiently. Cluster and fruit weights of the winter crop weighed significantly less than those of the summer crop. However, the contents of total soluble sugar and titratable acidity were higher than those of the summer crop. The anthocyanin content in the peel of the winter fruit was significantly higher than that in the summer fruit. The yield of the winter crop is controlled by the yield of the summer fruit. To maintain the stability of the two crops for one year, the ratio of yield in the winter to the summer should be controlled from 2:5 to 3:5 to ensure the sustainable production of two crops without overlap for ‘Summer Black’ grape. These results may help grape growers to overcome the impacts of rainy and hot climates with the help of protected facilities, and it could enable the use of solar radiation and heat resources in subtropical and tropical areas.

Dynamic changes in soil chemical properties and microbial community structure in response to different nitrogen fertilizers in an acidified celery soil

To determine the effects of different kinds of nitrogen fertilizer, especially high-efficiency slow-release fertilizers, on soil pH, nitrogen (N) and microbial community structures in an acidic celery soil, four treatments (CK, no N fertilizer; NR, urea; PE, calcium cyanamide fertilizer; and SK, controlled-release N fertilizer) were applied, and soil pH, total soil N, inorganic N, and soil microbial biomass C were analyzed. Phospholipid fatty acids (PLFAs) were extracted and detected using the MIDI Sherlock microbial identification system. The PE treatment significantly improved soil pH, from 4.80 to >6.00, during the whole growth period of the celery, and resulted in the highest celery yield among the four treatments. After 14 d application of calcium cyanamide, the soil nitrate content significantly decreased, but the ammonium content significantly increased. The PE treatment also significantly increased soil microbial biomass C during the whole celery growth period. Canonical variate analysis of the PLFA data indicated that the soil microbial community structure in the CK treatment was significantly different from those in the N applied treatments after 49 d fertilization. However, there was a significant difference (P<0.05) in soil microbial community structure between the PE treatment and the other three treatments at the end of the experiment. Calcium cyanamide is a good choice for farmers to use on acidic celery land because it supplies sufficient N, and increases soil pH, microbial biomass and the yield of celery.

Comparative Transcriptomic and Proteomic Analysis to Deeply Investigate the Role of Hydrogen Cyanamide in Grape Bud Dormancy

Hydrogen cyanamide (HC) is an agrochemical compound that is frequently used to break bud dormancy in grapevines grown under mild winter conditions globally. The present study was carried out to provide an in-depth understanding of the molecular mechanism associated with HC releasing bud dormancy in grapevines. For this purpose, RNA-seq based transcriptomic and tandem mass tag (TMT)-based proteomic information was acquired and critically analyzed. The combined results of transcriptomic and proteomic analysis were utilized to demonstrate differential expression pattern of genes at the translational and transcriptional levels. The outcome of the proteomic analysis revealed that a total of 7135 proteins (p-value ≤ 0.05; fold change ≥ 1.5) between the treatments (HC treated versus control) were identified, out of which 6224 were quantified. Among these differentially expressed proteins (DEPs), the majority of these proteins were related to heat shock, oxidoreductase activity, and energy metabolism. Metabolic, ribosomal, and hormonal signaling pathways were found to be significantly enriched at both the transcriptional and translational levels. It was illustrated that genes associated with metabolic and oxidoreductase activity were mainly involved in the regulation of bud dormancy at the transcriptomic and proteomic levels. The current work furnishes a new track to decipher the molecular mechanism of bud dormancy after HC treatment in grapes. Functional characterization of key genes and proteins will be informative in exactly pinpointing the crosstalk between transcription and translation in the release of bud dormancy after HC application.

Effect of Timing of Tilling after Application of Lime Nitrogen on Emergence and Seedling Establishment of Volunteer Rice (&lt;i&gt;Oryza sativa&lt;/i&gt; L.)

Effect of Timing of Tilling after Application of Lime Nitrogen on Emergence and Seedling Establishment of Volunteer Rice (&lt;i&gt;Oryza sativa&lt;/i&gt; L.)

Transcriptomic Study of Early Responses to the Bud Dormancy-breaking Agent Hydrogen Cyanamide in ‘TropicBeauty’ Peach

To determine how the dormancy-breaking agent hydrogen cyanamide (HC) advances budbreak in peach (Prunus persica), this study compared the transcriptome of buds of low-chill ‘TropicBeauty’ peach trees treated with 1% (v/v) HC and that of nontreated trees at 3 and 7 days after treatment (DAT), respectively, using an RNA sequencing analysis. The peak of total budbreak occurred 6 weeks earlier in the HC-treated trees (at 32 DAT) than the nontreated trees (at 74 DAT). There were 1312 and 1095 differentially expressed genes (DEGs) at 3 and 7 DAT, respectively. At 3 DAT, DEGs related to oxidative stress, including the response to hypoxia, lipid oxidation, and reactive oxygen species (ROS) metabolic process, were upregulated in HC-treated buds. Additionally, DEGs encoding enzymes for ROS scavenging and the pentose phosphate pathway were upregulated at 3 DAT but they were not differently expressed at 7 DAT, indicating a temporary demand for defense mechanisms against HC-triggered oxidative stress. Upregulation of DEGs for cell division and development at 7 DAT, which were downregulated at 3 DAT, suggests that cell activity was initially suppressed but was enhanced within 7 DAT. At 7 DAT, DEGs related to cell wall degradation and modification were upregulated, which was possibly responsible for the burst of buds. The results of this study strongly suggest that HC induces transient oxidative stress shortly after application, leading to the release of bud dormancy and, subsequently, causing an increase in cell activity and cell wall loosening, thereby accelerating budbreak in peach.

Budburst and flowering intensity by the spraying of dormancy-breaking products in ‘Eva’ apple trees

Spraying of dormancy-breaking chemicals is a mandatory procedure to produce temperate fruits in low-chill regions. Although hydrogen cyanamide (HC) + mineral oil (MO) show efficiency enhancing budburst, the usage of HC is restricted in some countries due to its toxicity. Therefore, this research aimed to evaluate the efficiency of spraying different dormancy-breaking agents on ‘Eva’ apple tree buds, under the conditions of the Depressão Central of Rio Grande do Sul, Brazil. Different doses of Erger® (0, 2, 3, 4, 5%) + 3% Ca(NO3)2 were tested and compared with MO (4%) or MO (4%) + HC (0.6%). Budburst rate of apical and axillary buds, physiological alterations in buds, return bloom, yield and fruit weight were evaluated. Erger® treatments efficiently enhanced budburst, with a result equivalent to HC + MO treatment. The budburst rate increased as the Erger® dose increased, also causing the increment of the return bloom in the following year. However, doses of 4 and 5% caused the death of shoots. The activity of the peroxidases and the content of H2O2 in the buds were affected by the treatments. Yield and fruit mass were different in response to treatments, although the effect varied between years. Erger® + Ca(NO3)2 spraying increase budburst in apical and axillary buds of ‘Eva’ apple tree in low-chill conditions and doses up to 3% of the commercial product do not cause toxicity.

Effects of gibberellins A4 on budbreak, antioxidant enzymes’ activity and proline content of flower buds in sweet cherry (Prunus avium)

Chilling accumulation is required for deciduous trees to maintain its normal growth and development. However, warm winters appeared more and more frequently, which hindered severely the normal growth and yield of fruit trees. To avoid these problems, artificial dormancy breaking agents are widely used. In our study, the effect of mineral oil, hydrogen cyanamide and gibberellins A4 (GA4) on budbreak were evaluated in sweet cherry (Prunus avium), which indicated that GA4 treatment hastened the date of flower budbreak and increased the percentage of budbreak compared with the other treatments. To better understand the mechanism of GA4-induced budbreak, the contents of antioxidant enzymes’ activity and proline in sweet cherry flower buds treated with GA4 and water were evaluated. There was a sharp decrease of catalase (CAT) activity after 5 days of GA4 treatment and then an increase of CAT activity after 10 days of GA4 treatment. However, there was a sharp increase of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) after 5 days of GA4 treatment and then a decrease of these enzyme activities after 10 days of GA4 treatment. There was a transient increase in hydrogen peroxide (H2O2) content and proline content after 5 days of GA4 treatment and a decrease after 10 days of GA4 treatment. However, there were only small fluctuations after water treatment, which indicated that temporary oxidative stress may contribute to the dormancy release of flower buds in the sweet cherry treated with GA4 through the regulation of H2O2 content coincided with the changes of antioxidant defense system.

Effect of the Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate on the Deep Placement of Nitrogen Fertilizers for Soybean Cultivation

The deep placement of urea fertilizer (DMU) containing 1% (W/W) of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on soybean growth and seed yield was as effective as those of the coated urea (CU) and lime nitrogen (LN) in a field research. The average seed yields were high in LN (464 g·m−2) and DMU (461 g·m−2) and relatively low in CU (405 g·m−2), U (396 g·m−2), and Cont (373 g·m−2) treatments. The accumulations of dry matter and nitrogen in soybean shoots were higher in the plants with deep placement of CU, LN, and DMU than U and Cont. The daily nitrogen fixation activity and daily nitrogen absorption rate were calculated based on the relative ureide method. Both nitrogen fixation activity and nitrogen absorption rate were higher in DMU, CU, and LN compared with control treatment, suggesting that the deep placement of DMU did not repress nitrogen fixation. Soil incubation test was performed using the same field soil with DMU, U, LN, and urea with DMPP 1%, 2%, and 4%. DMU inhibits nitrification similar to the pattern of LN until 8 weeks. The increasing DMPP concentration did not markedly increase the nitrification inhibition. From these results, it was concluded that urea fertilizer with 1% DMPP is efficient for deep placement of N fertilizer for soybean cultivation due to its lower price compared with CU and LN.

Effects of hydrogen cyanamide on physiological changes during endodormancy releasing and flowering of sweet cherries in warm region

A trial was conducted to verify the effect of hydrogen cyanamide (HC) application on endodormancy release and blooming of 'Summit' sweet cherry trees, as well as on carbohydrates, nitrogen content, and endogenous hormone. The use of HC hastened bud release, shortened the bloom period that resulted in improved fruit set. Moreover, the HC-treatment also led to a quick hydrolysis of starch. The increase in the contents of glucose, fructose and total nitrogen, and the decrease of sucrose and sorbitol contents were coincided with the process of endodormancy release and flowering when HC was applied to 'Summit' sweet cherry. In addition, gibberellic acids (GAs) might have selective effects in the process of endodormancy release and blooming. A higher GAs/ABA ratio was observed in HC-treated 'Summit' branches from endodormancy release until full bloom. As for indole-3-acetic acid (IAA) and cytokinins, the contents of IAA, Zeatin (ZT), Dihydrozeatin (DZ) and N(6) -(Δ(2) -isopentenyl) adenosine (2-ip) increased gradually during the processes of endodormancy release in 'Summit' sweet cherry trees. For IAA/ABA ratio, it also showed an increasing trend in this process. The results of this study confirmed that IAA, and cytokinins also play a certain role in promoting dormancy release of perennial plants, and the use of HC promoted the increase in IAA and cytokinins content.

ABA promotes starch synthesis and storage metabolism in dormant grapevine buds

In grapevine (Vitis vinifera L.) buds, the short day (SD)-photoperiod induces endodormancy and increases the level of ABA and the expression of ABA key biosynthesis genes, which suggests that ABA could be the mediator of the photoperiodic induction of endodormancy. In the present study, it was established that during the development of the endodormancy, the content of ABA and the accumulation of starch increased in parallel in the buds; however, these increases occurred after the buds were already in the state of endodormancy. Despite this finding the exogenous applications of ABA to single-bud cuttings increased the starch content and up-regulated the expression of starch synthesis genes (VvSS1 and VvSS3) and down-regulated the expression of sucrose metabolism genes, invertase (VvINV) and sucrose phosphate synthase (VvSUPS). In addition, the manipulation of the endogenous content of ABA in the grapevine buds by applications of hydrogen cyanamide and uniconazole-P, revealed that the depth of the endodormancy depends on the ABA levels. Taken together, the results indicate that the development of the endodormancy in grapevine buds is associated with the accumulation of starch and a shift in metabolism towards a storage metabolism; as ABA stimulates both processes, it must play an important role in the maintenance and release but not the induction of endodormancy in grapevine buds.

Effects of different ways of flower bud differentiation on bud germination and fruit quality of grape

In this study, 3 year-old ‘Xiahei’ grape was used as the test material. It aimed to promote the differentiation of grape flower buds with different concentrations of paclobutrazol and chlormequat chloride, and the effects of different ways of promoting the differentiation of flower buds on the germination of grape buds and fruit quality were studied. The results showed that different ways of flower bud differentiation could promote the germination of ‘Xiahei’ grape buds. In consideration of the fruiting habit, phenological period and fruit quality of different treatments, second fruits which were sprayed with 1000 times 15% paclobutrazolin had the best effect. On May 1, 2019 (One fruit sitting period) spraying grape new tip with 1000 times 15% paclobutrazol and 0.3% potassium dihydrogen phosphate, 0.1% boric fertilizer and the same fungicides, spraying again after 7 days, reagent type and concentration were same as the first time, after 10 days of the second spraying 2.5% hydrogen cyanamide was used to break dormancy of winter bud. The way could effectively promote grape secondary fruit and improve the quality of the grapes.

A COMPARATIVE STUDY BETWEEN GARLIC EXTRACT AND HYDROGEN CYANAMIDE ON FLOWERING, FRUIT SET AND PRODUCTIVITY OF GRAPES

A COMPARATIVE STUDY BETWEEN GARLIC EXTRACT AND HYDROGEN CYANAMIDE ON FLOWERING, FRUIT SET AND PRODUCTIVITY OF GRAPES