Phytosulfokine α (PSKα) delays senescence and reinforces SUMO1/SUMO E3 ligase SIZ1 signaling pathway in cut rose flowers (Rosa hybrida cv. Angelina)

Roses are widely used as cut flowers worldwide. Petal senescence confines the decorative quality of cut rose flowers, an impressively considerable economic loss. Herein, we investigated the SUMO1/SUMO E3 ligase SIZ1 signaling pathway during bud opening, and petal senescence of cut rose flowers. Our results exhibited that the higher expression of SUMO1 and SUMO E3 ligase SIZ1 during bud opening was accompanied by lower endogenous H2O2 accumulation arising from higher expression and activities of SOD, CAT, APX, and GR, promoting proline accumulation by increasing P5CS expression and activity and enhancing GABA accumulation by increasing GAD expression and activity. In harvested flowers, lower expressions of SUMO1 and SUMO E3 ligase SIZ1 during petal senescence were associated with higher endogenous H2O2 accumulation due to lower expression and activities of SOD, CAT, APX, and GR. Therefore, promoting the activity of the GABA shunt pathway as realized by higher expression and activities of GABA-T and SSADH accompanied by increasing OAT expression and activity for sufficiently supply proline in rose flowers during petal senescence might serve as an endogenous antisenescence mechanism for slowing down petals senescence by avoiding endogenous H2O2 accumulation. Following phytosulfokine α (PSKα) application, postponing petal senescence in cut rose flowers could be ascribed to higher expression of SUMO1 and SUMO E3 ligase SIZ1 accompanied by higher expression and activities of SOD, CAT, APX, and GR, higher activity of GABA shunt pathway as realized by higher expression and activities of GAD, GABA-T, and SSADH, higher expression and activities of P5CS and OAT for supplying proline and higher expression of HSP70 and HSP90. Therefore, our results highlight the potential of the PSKα as a promising antisenescence signaling peptide in the floriculture industry for postponing senescence and extending the vase life of cut rose flowers.

Features of growth and development of Abies alba Mill. seedlings in the conditions of Voronezh (Russia)

Phenological observations are one of the methods for studying the reaction of introduced species to new conditions and subsequent introduction into regional phytocenoses. This research wants to assess growth and development of Abies alba Mill., currentlyexotic in the Central Black Earth region of Russia. Seeds, obtained from individuals growing in the natural range (the Carpathians) in 1987 were sown in the university nursery. Then five-year-old seedlings were planted in the University arboretum. At the age of 22 the arboretum habitat was inferior to natural analogues. Phenological observations of bud opening and formation of annual growth coincide with the beginning of the growing season in natural plantings. High rates of seed germination (80%), high annual growth rates of seedlings (and transplanted plant) determined final success of silver fir in forest-steppe conditions. Precipitation has a dominant influence on growth and development, as shown by the correlation analysis between climate and growth, despite the fact that the species is drought-resistant in natural habitats. The study emphasizes the factors that control growth and development of silver fir. The use of this method of sowing is ecologically sound, which can further improve the success of species adaptation to the individual conditions of regional phytocenoses.

Effects of Different Preservatives on Cut Flower of Luculia pinceana: A Novel Fragrant Ornamental Species

Luculia pinceana is a potential cut flower because of its long-term blooming inflorescences and charming fragrance. However, its narrow distribution area and unexplored wild status severely restrict its applications, thus leading to the scientific research of cut L. pinceana flowers. To our knowledge, there is no available published information about the postharvest fresh-keeping of L. pinceana. During this study, the cut flowers of L. pinceana were tested using nine preservatives with different concentrations of sucrose and 8-hydroxyquinoline (8-HQ) to evaluate the fresh-keeping effects. Through the investigation and analysis of vase life, bud opening and abortion rate, water balance, malonaldehyde (MDA) content, and peroxidase (POD) activity, we selected and identified the best vase solution for cut L. pinceana flowers. The results suggested that the preservative of 1% sucrose and 100 mg/L 8-HQ could significantly prolong the vase life of cut L. pinceana flower up to 9 days compared with water control. This solution positively affects flower bud blooming, delays flower senescence, improves the water balance, inhibits the MDA accumulation, and increases POD activity. Therefore, this preservative is suitable for the fresh-keeping of cut L. pinceana flowers. Our study is the first to report the effects of preservatives on cut L. pinceana flower. The results showed that the low-sugar-containing (1% sugar) preservatives can effectively improve the ornamental quality of fresh flowers and demonstrated that the postharvest fresh-keeping of L. pinceana requires low sugar and is insensitive to microorganisms.

INFLUENCE OF VARIOUS HOLDING SOLUTIONS ON VASE LIFE OF CHRYSANTHEMUM CV. PUJA

The present experiment entitled “Influence of various holding solutions on vase life of Chrysanthemum (Dendranthema grandiflora) cv. Puja” was carried out under Complete Randomized Design with three replications in the Horticulture Laboratory of School of Agricultural Sciences and Technology RIMT University, Mandi Gobindgarh, Punjab during 2020. The result showed that the vase life was significantly affected by different holding solutions. Among the various treatments, T10 (Sucrose 6% + Citric acid 300ppm) was resulted in minimum number of days taken (3.22 days) for bud opening, fresh weight of spike (11.04 g), flower height (6.89 cm), stem diameter (4.85 mm), minimum moisture loss (44.44%), maximum vase life (19.33 days) and dry weight of spike (2.46 g). Whereas, treatment T9 (Sucrose 4% + Citric acid 200 ppm) was resulted in maximum total solution consumption (24.00 ml). Maximum diameter of the flower on 6th, 9th and 15th days of experiment was recorded in treatment T10 (Sucrose 6% + Citric acid 300 ppm). Treatment T9 (Sucrose 4% + Citric acid 200 ppm) was also resulted in maximum diameter of the flower on 3rd and 12th day of trial. Treatment T10 (Sucrose 6% + Citric acid 300 ppm) was resulted in maximum weight of spikes on 3rd, 6th and 9th day of experiment. And also maximum weight of spikes on 12th and 15th days of trial was observed in treatment T9 (Sucrose 4% + Citric acid 200 ppm).

Features of spring vegetation of hazel leaves in the foothills of the Republic of Adygea

The article provides information about one of the areas of work associated with hazel carried out by the Adygh branch of the Federal State Budgetary Institution of Science «Federal Research Center «Subtropical Scientific Center of the Russian Academy of Sciences». The territorial location of this institution is the foothills of the Republic of Adygea, where the objects of the research, i.e. forms and varieties of hazel are located. The institution has been studying hazel since 1995. The article provides data on the collection site where the best forms and known varieties of hazel grow. At the collection site, phenological observations of hazel were carried out from 2017 to 2019. The information is given on the number of forms and varieties of hazel growing on the collection site, on the features of spring vegetation of leaves. The expression «spring vegetation of hazel leaves» implies several spring phenological phases of hazel, such as «beginning of leaf bud swelling»; «massive swelling of leaf buds»; «beginning of leaf bud opening» and «the maximum length of the leaf plate is 5 cm». The meteorological indicators of the studied period from 2017 to 2019 have been indicated. The article discusses the prospects of certain forms and varieties for various breeding purposes. Based on the data presented, it has been concluded that: 2017 was the most unfavorable of the three years of research in the meteorological plan; the earliest leaf vegetation during the three years of research was observed in the «Zakatala» variety; the leaf reaches 5 cm in the «Trapezund» variety and the «Futkurami» variety the very first, and the 20/15 form.

Involvement of Ethylene in Physiological Processes Determining the Vase Life of Various Hybrids of Mokara Orchid Cut Flowers

There is limited information about the postharvest performance and physiology of Mokara orchid cut flowers, which are a special group of artificially created trigenetic hybrids of Vanda × Arachnis × Ascocentrum. Therefore, we first characterized the patterns of various physiological parameters during vase life of five Mokara hybrids, which differ in their longevity. Then, we examined the effects of ethephon and ethylene inhibitors on these physiological parameters, and on parameters of the ethylene biosynthesis pathway, during vase life of two selected Mokara hybrids, “Moo-deang” and “Dao-lai”, which showed significant differences in their vase life duration and senescence symptoms. The results demonstrate that the differences in vase life longevity among the five Mokara hybrids are due to differences in their ethylene production rates, which regulate flower development processes expressed in bud opening and floret senescence. The results clearly show that ethylene is involved in the regulation of the Mokara flower senescence, and pretreatment with ethylene inhibitors significantly improved their vase life longevity. Thus, ethylene seems to be the main factor that determines the longevity differences of the Mokara hybrids, rather than their water relations parameters. This study can serve as a research tool for developing effective postharvest treatments for Mokara hybrids.

Conditioning Machine Learning Models to Adjust Lowbush Blueberry Crop Management to the Local Agroecosystem

Agroecosystem conditions limit the productivity of lowbush blueberry. Our objectives were to investigate the effects on berry yield of agroecosystem and crop management variables, then to develop a recommendation system to adjust nutrient and soil management of lowbush blueberry to given local meteorological conditions. We collected 1504 observations from N-P-K fertilizer trials conducted in Quebec, Canada. The data set, that comprised soil, tissue, and meteorological data, was processed by Bayesian mixed models, machine learning, compositional data analysis, and Markov chains. Our investigative statistical models showed that meteorological indices had the greatest impact on yield. High mean temperature at flower bud opening and after fruit maturation, and total precipitation at flowering stage showed positive effects. Low mean temperature and low total precipitation before bud opening, at flowering, and by fruit maturity, as well as number of freezing days (<−5 °C) before flower bud opening, showed negative effects. Soil and tissue tests, and N-P-K fertilization showed smaller effects. Gaussian processes predicted yields from historical weather data, soil test, fertilizer dosage, and tissue test with a root-mean-square-error of 1447 kg ha−1. An in-house Markov chain algorithm optimized yields modelled by Gaussian processes from tissue test, soil test, and fertilizer dosage as conditioned to specified historical meteorological features, potentially increasing yield by a median factor of 1.5. Machine learning, compositional data analysis, and Markov chains allowed customizing nutrient management of lowbush blueberry at local scale.

Adjusting Mineral Nutrition of Lowbush Blueberry to Agroecosystem Conditions

Nutrient management of lowbush blueberry (Vaccinium angustifolium Ait.) depends on several yield-limiting features. Machine learning models can process such yield-impacting variables to predict berry yield. We investigated the effects of local variables on yields and nutrient management of lowbush blueberry. We collected 1504 observations from N-P-K fertilizer trials conducted in Quebec, Canada. Meteorological indices at various phenological stages showed the greatest impact on yield. High mean temperature at flower bud opening and after fruit maturation, and total precipitation at flowering showed positive effects. Low mean temperature and low total precipitation before bud opening, at flowering, and by fruit maturity, as well as number of freezing days (&lt; -5&ordm;C) before flower bud opening, showed negative effects. Soil fertility variables, leaf nutrient compositions and N-P-K fertilization showed smaller effects. Gaussian processes predicted berry yields from historical weather data, soil analysis, fertilizer dosage, and leaf nutrients with a root-mean-square-error of 1447 kg ha-1 on the testing data set. An in-house Markov chain algorithm optimized yields modelled with Gaussian processes from leaf nutrient composition, soil test value, and fertilizer dosage conditioned to specified historical weather features. We propose to use conditioned machine learning models to manage nutrients of lowbush blueberry at local scale.