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Short growing seasons in regions with cold or semi-cold climates are a major obstacle to commercial grape production, as they negatively impact the quality and quantity of the crop yield, mainly due to insufficient uniform bud break. Consequently, this study evaluated the effects of foliar application of hydrogen cyanamide (Dormex) solution at 0% (control) and 1% concentrations on 10-year-old ‘Askari’ grape (Vitis vinifera‘Askari’) trees. The aim was to investigate hydrogen cyanamide as a rest-break agent and understand its physiological and biochemical mechanisms related to bud dormancy release in regions with cold/semi-cold climates. The results showed that catalase activity decreased in hydrogen cyanamide-treated buds (1%) compared to untreated control samples during the second, third, and fourth sampling dates. Correspondingly, hydrogen peroxide accumulated in the treated buds during this period. Putrescine concentration increased over six-fold with 1% hydrogen cyanamide application compared to initial levels during dormancy release. In contrast, spermine and spermidine concentrations significantly declined by about 90 and 80%, respectively. Hydrogen cyanamide also increased total nitrogen concentration in buds and attributed to elevated amino acids like proline, glutamine, arginine, ornithine, and citrulline. In conclusion, the findings indicate that hydrogen cyanamide application enhanced bud break by 7.78 and 6.67% at 20 and 30 days after treatment compared to controls. Our findings suggest hydrogen cyanamide can induce bud break by altering activity of antioxidant enzymes, the concentration of polyamines, amino acids, and nitrogen.

Broadband sensing and spectroscopy in millimeter wave and subterahertz frequencies can be facilitated with CMOS coherent detectors as a low-power, low-cost solution. This article presents a fully integrated coherent detector with a broadband frequency comb as an on-chip reference signal. The receiver incorporates a frequency comb generator, which provides a broadband comb as a reference for heterodyne detection, and an NMOS field-effect transistor as the heterodyne detector. It also includes an on-chip elliptical antenna with a periodic structure that enhances its directivity up to +10 dBi without using a lens. The receiver detects any arbitrary spectrum from 50 to 280 GHz with a resolution of 2 Hz by tuning the comb spacing of the reference signal from 100 MHz to 5 GHz. The chip is implemented in a standard 65-nm-CMOS process and it consumes 34-mW dc power.

The objective of present study was to evaluate the impact of time of application of nitric oxide (NO) on mineral composition of strawberry ‘Selva’ plants under saline conditions. Well-rooted daughter plants were planted in 3L plastic pots filled with 1:1 (v/v) ratio of peat moss and perlite and grown under the greenhouse conditions (21 ± 2/17 ± 2°C and RH = 60 ± 5% under natural sunlight). After full establishment of plants they were divided into 10 groups: control, plants sprayed with distilled water and exposed to 40 mM NaCl salinity stress, plants sprayed with 50 or 75 μM NO solutions under non-stress conditions, and plants sprayed with 50 or 75 μM NO solutions at three different application times, one week before, at the beginning, and one week after initiation of 40 mM NaCl salt stress. Results indicated that concentrations of macro-nutrients, Fe and Zn in shoots and roots were decreased due to salinity stress. The NO application, regardless of time of application and level, mitigated the deleterious effect of salinity on minerals uptake. Time aspect of NO application was important as plants received 75 μM NO solution, one week before initiation of salt stress had higher shoot N, K, and Ca concentration, productivity and leaf relative water content as compared with those received NO solution at the same concentration, one week after exposure to salt stress. Higher K/Na ratio of shoot was also observed in plants treated with 75 μM NO solution one week before start of salinity compared with salt-stressed, non-NO-treated plants. It seemed that time of NO application could change the strategy of plant against stress.

This study was conducted to evaluate enzymatic and non-enzymatic antioxidant response of ‘Selva’ strawberry plants on exogenous nitric oxide under saline conditions with respect to time of application. Sodium nitroprusside (SNP), as nitric oxide (NO) source, was applied on the leaves by spray before, simultaneously, or after the initiation of saline stress. Results indicated that salinity and/or SNP at concentrations of 50 and 75 μM caused increase in activity of antioxidant enzymes, such as catalase, superoxide dismutase, glutathione reductase, ascorbate peroxidase and peroxidases as well as leaf content of proline, glycine betaine and total phenolics in comparison to control. Time of NO application was important because the highest levels of catalase and ascorbic peroxidase were in plants pre-treated with SNP one week before the initiation of salinity stress. Plants from these combinations had the highest fruit yield among all saline stressed plants. So, it seems that earlier application of SNP is more effective for an optimised protection against deleterious influence of salinity stress, because pre-treated plants had a sufficient time to develop an appropriate antioxidant response. The application of SNP simultaneously or after exposure of plants to stress conditions, was also helpful in increasing plant tolerance but to a lesser extent.

AbstractIn order to evaluate the influence of salinity and time of application of nitric oxide (NO) on aroma composition and quality of Selva strawberry fruits, the present study was carried out. Treatments included: control, plants sprayed with 75 μM NO solution, plants exposed to 40 mM NaCl salinity stress and plants exposed to 40 mM NaCl and sprayed with 75 μM NO solution 1 week before, simultaneously and 1 week after start of salinity stress. Results of headspace analysis of the fruits aroma and quality parameters indicated that saline conditions modified aroma composition and some quality parameters as ethylbutanoate percentage in aroma was one fifth and ethtyl 2-methyl butanoate was one third of control samples. Salinity caused reduction of TSS and ascorbic acid concentration. Application of NO on plants grown under saline conditions lead to increment of aroma quality as ethyl isovalerate was detected only in aroma of these categories of plants, and concentration of vitamin C and total anthocyanins increased in plants treated with NO. Plants treated with NO at different times had various volatile compounds with different share. For example ocimenone was detected only in fruits treated with NO 1 week before start of salinity stress. Highest amount of total polyphenol compounds and anthocyanins were obtained from plants treated with NO 1 week before or simultaneously with start of salinity stress.