Bud Swelling Research Articles

The fruit quality and nutrient content of kiwifruit produced by organic versus chemical fertilizers.

Currently, organic farming has become a feasible approach for the production of high-quality fruits. To evaluate the response of fruit quality and mineral nutrition contents of Hayward Kiwifruit affected by different organic and inorganic fertilizers, the present study was conducted in Citrus and Subtropical Fruits Research Center, Iran, in 2017-2021, as a randomized block design with three replications. The studied treatments were organic fertilizers (cow, vermicompost and Azolla) and chemical fertilizers. After 4 years of fertilization, the fruit's nutritional elements content and some fruit bioactive compounds were evaluated after 3 months of cold storage and then analyzed by the principal component analysis (PCA) method. The use of organic amendments boosted the calcium, phosphorus, potassium and iron content of the kiwifruits compared to chemical fertilizers. The highest fruit potassium and phosphorus content were recorded in the cow manure treatment. The lowest amount of nitrate and the highest calcium, zinc, copper and manganese accumulation were recorded in the fruits treated with vermicompost. In addition to mineral nutrients, the dry matter, total soluble solids, total phenolic and antioxidant capacity of kiwifruit were improved by the application of vermicompost amendment compared to the other fertilizer sources. However, the highest fruit vitamin C and total soluble carbohydrates were measured in the cow manure treatment. The PCA results of the fruit quality indices indicated that fertilization treatments were ranked as vermicompost (1.88) > cow manure (1.63) = chemical (1.60) > Azolla (1.54). It is concluded that the application of 40 kg of vermicompost or 40 kg of cow manure in the next rank in Hayward kiwifruit orchards in March (growth stage beginning of bud swelling) may be a more suitable approach for improving the nutritional quality of the fruit. © 2024 Society of Chemical Industry.

A satellite-field phenological bridging framework for characterizing community-level spring forest phenology using multi-scale satellite imagery

Forest phenology, as a sensitive indicator of a forest’s response to climate change and variability, has long been monitored using remote sensing, yet has seldom been interpreted or validated with spatially compatible, community-level field phenological observations. In temperate deciduous forests, multiple spring phenological phases are critical for modeling carbon storage and biogeochemical cycles. The simultaneous detection of all these critical phenological phases at the community level remains a long-standing challenge. To tackle these challenges, the objective of this study is to develop a novel satellite-field phenological bridging framework for characterizing all key spring phenological phases of a fragmented deciduous forest using multi-scale satellite time series. The framework consists of four key components: deep learning-based spatiotemporal image fusion, satellite-based forest phenology modeling, satellite-based forest phenological metric extraction, and field-based forest community phenological characterization. With the devised framework, we extract a total of 24 satellite phenological metrics of Trelease Woods, a forest fragment near Urbana, IL, USA. From weekly field phenological observations of 148 canopy trees of 15 common species of the forest community, we devise three summative field phenological indices to characterize community-level phenological states in spring. Under the satellite-field bridging framework, events during each key spring forest phenological phase (i.e., bud swell, budburst/leafing out, leaf expansion, and leaf maturity) are successfully detected using the fusion imagery (MAE from 1.1 to 2.9 days and bias from -2.4 to 1.5 days). However, the satellite detection of the earliest field events may be influenced by understory plants, soil background, and snow. The subsequent multi-scale, satellite phenological analysis underscores the importance of taking into account spatial scale and representation from both satellite and field phenological perspectives in building corresponding bridging relationships. Among the extracted pheno-metrics, bridging the threshold-based metrics to field phenological indices results in the highest accuracy (MAE less than 3 days and bias less than 2 days). The strong agreement among the field indices demonstrates the effectiveness of our field phenological surveying approach in generating community-wide forest phenological representation. Our study innovatively scales up the field phenological observations from the individual trees to the species to the community level, and the devised framework enables accurate retrieval of all key phenological events of community-wide, spring canopy development of the forest fragment.

Pinus sibirica Du Tour в условиях интродукции на примере Полярно-альпийского ботанического сада-института

The study has been conducted at the Polar-Alpine Botanical Garden-Institute, the northernmost botanical garden in Russia (67°38′ N). The aim of this work has been a comprehensive analysis of the condition of Siberian stone pine trees (Pinus sibirica Du Tour) during their introduction in the Arctic. The condition of 8 specimens of the species cultivated at the experimental plot in the town of Apatity has been examined. Their phenological development has been analyzed: the swelling and breaking of the vegetative buds, the end of the elongation and maturation of the needles, the beginning and end of growth of the annual shoots, the lignification of the shoots, the beginning and end of pollen dispersion. The degree of lignification of the annual shoot, the winter hardiness, the habit, the shootforming capacity, the height increment, the generative development and the reproduction in the plantation have also been assessed. The risk of a tree falling has been determined by considering its surroundings and exposure to wind. The root zones, the butts, the trunks, the crown bases, the boughs and the crowns have been examined for the presence of hollows, cracks, decomposition, fungal fruit bodies, damage, weak forks, dead branches, etc. The application of an approach combining the analysis of seasonal development, viability and risk of tree fall is promising for a comprehensive and objective assessment of the condition of Siberian stone pine trees by morphological and phenological characteristics during the introduction to the Arctic zone of the Russian Federation. The phenological rhythm of the studied trees corresponds to the environmental conditions during the introduction to the Polar-Alpine Botanical Garden-Institute named after N.A. Avrorin. Vegetation begins in late May. By the end of August the annual shoots lignify, which indicates the readiness of the plants for the winter period. The close timing of the onset of phenophases and their low variation may indicate a low dependence of the seasonal development of Siberian stone pine on weather conditions during the introduction to the central part of the Kola Peninsula. The trees are winter-hardy, retain the life form inherent to the species, have a high shoot-forming capacity and annual height increment. They reach the generative stage of development. For their propagation in the plantation, it is necessary to attract seed material from other regions. The trees are monocormic, unimucronate and bimucronate. They are characterized by dense crowns. Their apical and lateral shoots are developed. In rare cases, the increment of lateral shoots is reduced. The V-shaped forks have been noted on the stems and a hollow in the butt area has been found on one of the trees. An additional instrumental examination is needed to determine the effect of diseases or pathogens on the stability of the trees.

Investigation of the local pear genotypes grown in Malatya

This study was carried out between 2020 and 2021 on local pear genotypes grown in the Malatya region (Türkiye), especially in the yard of Apple-Pear Germplasm of Malatya Turgut Özal University. In the study, phenological, pomological, and phytochemical characteristics of nine pear genotypes were analyzed. The following dates were identified for the selected characteristics: the bud swell between March 9 and 27, the bud bursts between March 14 and April 1, the start of flowering between March 28 and April 7, full bloom between April 2 and 11, the end of flowering between April 6 and 15, harvest between August 10 and November 13, defoliation between December 3 and 17, and the number of days from full bloom to harvest ranged between 128 and 216 days. The following results were obtained: fruit weights were 46.3-202.6 g, fruit lengths were 44.8-91.2 mm, fruit diameters were 43.8-76.2 mm, fruit flesh firmness were 2.4-9.62 kg/cm2, fruit volume was 45.5-204.3 ml, and fruit color values were 21.3-77.1 as L value, -2.49-0.1 as a value, and -2.03-54 as b value. The water-soluble dry matter content of the genotypes ranged between 10.3-15.9, pH values ranged between ​​3.99-5.37, total phenolic content ranged between 167-992 mg GAE /1000g, and total antioxidant activities ranged from 284 to 1454 mg TEAC/1000 g. Aliseydi from the summer pear genotypes and Parlak and Armut1 genotypes from the autumn genotypes were important. It is thought that Biber, Dudunun and Efendi genotypes from winter genotypes may be important materials for future studies.

CLIMATOGENIC INFLUENCE AND PREDICTION OF SEASONAL RHYTHM CHANGES IN THE MAIN FOREST-FORMING SPECIES OF THE NORTHEASTERN CARPATHIANS

The article is devoted to the study of the phenological phenomena of the main forest-forming species (European spruce - Picea abies, white fir - Abies alba and forest beech - Fagus sylvatica) within the temperate climate zone (600-800 m a.s.l.) on the territory of the Carpathian National Nature Park for the period 2000-2022. The study employed a comprehensive set of field, instrumental, laboratory, analytical, and mathematical-statistical research methods, along with certain approaches applied in phenology and meteorology. According to the results of the statistical analysis, a significant influence of precipitation in March on the beginning of bud swelling (Picea abies and Fagus sylvatica species), the beginning of flowering trees (Picea abies, Abies alba species) and the onset of fruit ripening (Picea abies, Fagus sylvatica species) was revealed. and the beginning of seed dispersal (Picea abies, Abies alba species). It should be noted that the minimum air temperatures in July significantly affect phenological events that begin and continue at this time and later, in particular, the beginning of fruit ripening (Abies alba, Fagus sylvatica species) and the onset of seeds dispersal (in all species). Strong and moderate correlations between January-February maximum temperatures and various phenological events (e.g., in Picea abies, dates of shoot growth and flowering initiation; in Abies alba, dates of flowering initiation and seed ripening initiation; in Fagus sylvatica, dates of bud swelling and flowering initiation) suggest a notable impact of underground water, originating from meltwater during this period, on plant seasonal rhythms. The most difficult for modeling was the phenomenon of the beginning of flowering of trees, the formation of which is influenced by all involved climate predictors - precipitation, minimum and maximum air temperatures. Based on the results of the research, the initial long-term forecasting of the response of local forest crops to probable climate changes was carried out; so, it was shown that even under the worst-case scenario (RCP 8.5), the dates of occurrence of all phenological phenomena of model tree species will be within the scope of the sample of actual data for the observation period of 2000-2022.

Aspectos fenológicos e produtivos de variedades de uvas submetidas a duas épocas de poda no Vale do Rio do Peixe-SC

Abstract: Pruning of grape varieties for processing typically occurs in winter. However, due to challenges in availability and labor costs, there is interest in shifting this practice to autumn—a period with lower demand for vineyard activities. This study aimed to assess the direct influence of autumn pruning on the phenological and productive performance of Niágara Rosada, Isabel Precoce, and Bordô varieties in the Vale do Rio do Peixe region, SC. Experiments were conducted during the 2015, 2016, 2017, and 2018 harvests in fully productive commercial vineyards located in Videira-SC. Pruning occurred in May (autumn) and August (winter). Autumn pruning took place when approximately 5% of the leaves had fallen, and the rest had turned yellow. Winter pruning occurred during the bud swelling stage. Weekly phenological monitoring, as well as measurement of the plants’ productive characteristics and the physical-chemical composition of the grapes, were conducted. Autumn pruning enhanced the productivity, average bunch weight, and uniformity of maturation for Niagara Rosada but accelerated the bud break for this variety in Vale do Rio do Peixe, SC, Brazil. In Bordô, autumn pruning did not affect productivity, but it advanced bud break. Conducting autumn pruning for four consecutive years decreased the productivity of Isabel Precoce.

PHENTHAUproc – An early warning and decision support system for hazard assessment and control of oak processionary moth (Thaumetopoea processionea)

The incidence of oak processionary moth (OPM), Thaumetopoea processionea L. (Lep., Notodontidae), in Central Europe has increased since the 1990s. Given potential climatic and land-use changes, increased abundance and range expansion of OPM may occur in the future. These changes could lead to more severe defoliation of oaks and higher threats to humans and animals, caused by the urticating hairs (setae) released by OPM larvae. These negative impacts on oak trees, people and animals urgently require effective hazard mitigation strategies.For OPM hazard assessment and decision support on OPM monitoring and control, the online early warning system “PHENTHAUproc – phenology modelling of Thaumetopoeaprocessionea” was created and validated. PHENTHAUproc implements daily updated temperature-based procedures to calculate the phenological development of OPM and to model the host trees’ phenology, i.e. bud swelling and leaf unfolding of Quercus robur L.The hatching date of the first instar larvae (L1) is calculated using three different already existing models. To determine the onset of L1 feeding, a bud swelling model for Q. robur was generated for the first time. The phenological development of OPM larvae and pupae is predicted by a model which was first created based on laboratory rearing data for the distinct development stages.Moreover, an existing leaf unfolding model for Q. robur was included into PHENTHAUproc. The predicted date of leaf unfolding can be complemented by in situ observations of leaf unfolding by the German Meteorological Service (DWD). The predicted dates of leaf unfolding and OPM forth instar development are used to define the optimal timespan for control measures such as the prophylactic spraying of biological insecticides. In addition, modelling of larval and pupal development can be used to estimate the seasonally increasing hazard resulting from setae dissemination, as well as to calculate the onset of monitoring of flying moths with pheromone traps.PHENTHAUproc provides phenological forecasts on a local and regional level, i.e. for weather station locations and raster maps countrywide. The models can be used anywhere in Europe as soon as air temperature data and information on potential adaptations of OPM to local climate and host tree phenology are available. This enables phenological forecasts for timely and effective protection of oak tree vitality as well as human and animal health against OPM-related hazards.

Pre-bloom control of pear psylla (Cacopsylla pyricola) using chemical compounds in combination with yellow sticky traps

Cacopsylla pyricola (Foerster) (Hemiptera: Psyllidae) is an important pest of pear in Iran. This study was carried out to evaluate the combination of using chemical compounds with yellow sticky traps for control of the pest at pre-bloom stage of pear trees. The experiments were performed using three treatments (2% oil and sticky traps, 1% oil plus Pyriproxyfen and sticky traps, and 1% oil plus fenoxycarb-lufenuron and sticky traps) along with the untreated control in a randomized complete block design. Treatment spraying was performed at bud swelling stage of pear trees, and then four yellow sticky traps were placed on tree branches in all treatments but the control. All the treatments were replicated three times. The mortality data were subjected to one-way ANOVA. The results showed combination of the tested compounds and yellow sticky traps could reduce the pest population up to 99.8%. The findings indicated that 2% oil in combination with sticky traps is very effective in controlling psylla.

PHENOLIC COMPOUNDS DASIPHORA MANDSHURICA DEPENDING ON THE PHASE DEVELOPMENT

Results of seasonal changes of phenolic compounds are presented in the article for leaves of Dasiphora mandshurica grown in culture of the south of the Amur Region. The phenolic compounds were analyzed by the method of a high-performance liquid chromatography. Six glycosides of flavonol (hyperoside, isoquercitrin, rutin, avicularin, quercitrin, astragalin), two aglycones (quercetin and rhamnetin) and tannins (ellagic acid and its glycoside) were found. It was found that phenolic composition of D. mandshurica is constant, but the changes of qualitative composition occur at the expense of minor compounds. The largest number of phenolic components (25) was established in stage the period of bud swelling of the leaf buds and periods of beginning and the mass of a blossoming. A higher total content of phenolic compounds in leaves of D. mandshurica was established in the stages the period of full isolation of leaves (35.3 mg/g), of total aglycones – in the period of ending of a blossoming (0.48 mg/g), and of total flavonols – in the period of mass blossoming (22.2 mg/g). Quercetin, kaempferol, rhamnetin glycosides were found in all stages of development. The largest glycosides of flavonol were found in the phases of the vegetation, budding and blossoming, and aglycones (quercetin and rhamnetin) at the beginning of vegetation and the ending of a blossoming. A fact of contrariety of the dynamics of accumulation of glycosides and their aglycones was revealed. A higher content of most individual phenolic compounds was found as in young leaves in the vegetation and budding, so in mature leaves in the blossoming phase. Avicularin and hyperoside are the predominant glycosides during the growing season. A higher content of the tannins was established in young leaves, ellagic acid dominated in the phase of the vegetation whereas ellagic acid glycoside was the predominant in the phase of the budding.

Induction of Axillary Bud Swelling of Hevea brasiliensis to Regenerate Plants through Somatic Embryogenesis and Analysis of Genetic Stability.

To overcome rubber tree (RT) tissue culture explant source limitations, the current study aimed to establish a new Hevea brasiliensis somatic embryogenesis (SE) system, laying the technical foundation for the establishment of an axillary-bud-based seedling regeneration system. In this study, in vitro plantlets of Hevea brasiliensis Chinese Academy of Tropical Agricultural Sciences 917 (CATAS 917) were used as the experimental materials. Firstly, the optimum conditions for axillary bud swelling were studied; then, the effects of phenology, the swelling time of axillary buds (ABs), and medium of embryogenic callus induction were studied. Plantlets were obtained through somatic embryogenesis. Flow cytometry, inter-simple sequence repeat (ISSR molecular marker) and chromosome karyotype analysis were used to study the genetic stability of regenerated plants along with budding seedlings (BSs) and secondary somatic embryo seedlings (SSESs) as the control. The results show that the rubber tree's phenology period was mature, and the axillary bud induction rate was the highest in the 2 mg/L 6-benzyladenine (6-BA) medium (up to 85.83%). Later, 3-day-old swelling axillary buds were used as explants for callogenesis and somatic embryogenesis. The callus induction rate was optimum in MH (Medium in Hevea) + 1.5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) + 1.5 mg/L 1-naphthalene acetic acid (NAA) + 1.5 mg/L Kinetin (KT) + 70 g/L sucrose (56.55%). The regenerated plants were obtained after the 175-day culture of explants through callus induction, embryogenic callus induction, somatic embryo development, and plant regeneration. Compared with the secondary somatic embryo seedling control, axillary bud regeneration plants (ABRPs) were normal diploid plants at the cellular and molecular level, with a variation rate of 7.74%.

Efficiency of application of different apple trees protection systems against harmful organisms in the Precarpathian province of the Carpathian mountain area of Ukraine

Goal. Study of the efficiency of application of chemical, biological and biological-chemical protection systems of apple trees against harmful organisms in the conditions of the Precarpathian province of the Carpathian mountain zone of Ukraine.
 Methods. Phytosanitary monitoring was carried out visually and with the help of pheromone traps. Phytophagous colonization and disease development were recorded according to generally accepted methods in the phases of apple development: «swelling of buds», «green cone», «bud extension», «bud separation», «pink bud», «blooming», «end of flowering», «fruit formation», «fruit growth» and «fruit ripening». The technical effectiveness of insecticides was determined after 5 and 7 days, and the effectiveness of fungicides — after 7 days. Statistical processing of research results was carried out by the method of variance analysis.
 Results. The results of monitoring the phytosanitary state of apple plantations established that the most common pests in 2018—2020 in the conditions of the Precarpathian Province of the Carpathian Mountain Zone of Ukraine were: apple fruit borer (37.2%), aphids (19.5%), leafhoppers (12.2%), mites (8.0%), apple moth (8.3%), flower eater (7.9%), hairy deer (6.9%); the most common diseases: scab (38.2%), powdery mildew (32.8%), moniliosis (14.2%), fruit rot (14.8%). All studied apple tree protection systems against harmful organisms in the conditions of the Precarpathian province of the Carpathian mountain zone of Ukraine obtained high yield rates, and all protection systems allowed to reliably protect apple orchards from pests and diseases. The technical efficiency of the chemical protection system, which included 12 treatments with chemical pesticides, averaged 82.5—96.5%. Productivity using this system was 26.5—26.7 t/ha. The biological protection system, which was based on 7 treatments with biological preparations, made it possible to obtain an apple yield 22.4—22.9 t/ha. The technical efficiency of the preparations of the biological defense system was at the level 66.1% — 72.3%. The system of biological and chemical protection of apple trees against harmful organisms included 7 treatments, reducing the use of chemical protection agents to one treatment, which made it possible to significantly reduce the amount of chemical agents used, minimize the negative impact of pesticides on the ecosystem of the apple orchard, and obtain productivity 23.5—25.1 t/ ha, for the effectiveness of drugs 66.3 94.3%.
 Conclusions. When apple orchards are heavily colonized by pests and diseases, it is recommended to use a chemical protection system that includes 12 treatments with chemical pesticides (9 treatments with a mixture of insecticides and fungicides, 2 treatments with fungicides and one treatment with insecticides) in accordance with the 12 main phases of apple tree development in which the most harmful organisms inhabit and damage the ecosystem of the apple orchard during the period from the «green cone» phenophase to the «fruit ripening» phenophase. To reduce the use of chemical protection agents in apple orchards, a biological and chemical system should be used: in the «green cone» phenophase, one treatment with chemical pesticides, and in the «end of flowering» phenophase — «fruit ripening» — with biological preparations. Under the condition of complete withdrawal from the use of chemical pesticides, the system of biological protection of the apple tree should be used, which is based on seven treatments with biological preparations in the phenophase «separation of buds» — «ripening of fruits».

The Impact of Systematic Insecticides Against Emerald Ash Borer on Phenology of Urban Ash Trees.

The continued threat of emerald ash borer (Agrilus planipennis; EAB) to North American ash trees (Fraxinus spp.) has necessitated the use of systemic insecticide treatments as a primary control strategy against EAB in urban centers. Altered tree phenology due to systemic insecticides could mediate nontarget effects on other insect species, such as seed weevils or leaf-feeders, but whether such injections alter phenological events has not been studied. This study assessed the effects of systemic injections of emamectin benzoate or azadirachtin relative to untreated controls on the spring and fall phenology of mature green ash trees in Saint Paul, MN, USA from fall 2017 to spring 2019. EAB was first detected in this area in 2009. Trees showed minor, visible signs of EAB infestation at study initiation, but not mortality. We examined six phenological events: bud swelling, budburst, flowering, leaf out, leaf color change, and leaf abscission using a visual survey protocol. The timing of phenological events was similar across the different treatments for all but two of events; budburst and flowering. Budburst and flowering occurred 7 d and 5 d earlier, respectively, in treated trees than untreated trees. Given symptoms observed, we posit that delays in these events in untreated trees were due to infestations of EAB and the treatments of emamectin benzoate or azadiractin simply preserved the original phenology. The results from this study suggest that systemic insecticides may mitigate changes in ash tree phenology such as delayed leaf out that may be early symptoms of emerald ash borer.

OPTIMIZATION OF THE NUTRIENT MEDIUM FOR THE PRIMARY STAGES OF COMMON WALNUT MICROCLONAL PROPAGATION IN VITRO

SummaryAim. To optimize the processes of microclonal propagation of Juglans regia in vitro by selecting the composition and consistency of the nutrient medium. Methods. The methods of in vitro culture establishment of initial explants and microclonal propagation were used. Parts of the stem and buds of young sprouts, germinated by the mini-greenhouse method from the seeds of Juglans regia, were used as initial explants. Murashige&Skoog (MS) and Driver&Kuniyuki (DKW) nutrient media were used to establish Juglans regia explants in vitro. Agar was used as a gelling agent. The solid, semi-liquid, and liquid media were prepared with addition of 7 g/l, 3.5 g/l and 0 g/l of agar, respectively. All experimental variants of the media were modified by adding the phytohormone of the cytokinin group 6-BAP. The pH of the medium was controlled at the level of 7.1–7.2. The established explants in vitro were cultivated at a temperature of + 25°C, a light intensity of 2500 lux, a relative humidity of 56–70% and a photoperiod 16/8 h light/dark. On the 3rd, 7th and 14th day, the survival rate, growth and development parameters of the initial explants were estimated. Results. It was found that the optimal nutrient medium for in vitro establishment and cultivation of Juglans regia is the DKW medium, on which the high survival rate of explants was observed (80%), as well as accelerated swelling of buds and their proliferation. It is proposed to use semi-liquid nutrient media for in vitro establishment of initial Juglans regia explants. The use of semi-liquid nutrient medium DKW for the initial stages of common walnut micropropagation in vitro contributed to the acceleration of the processes of reproduction of this culture by 2 days and improved the survival rate by 20% compared to solid medium. Conclusion. The use of semi-liquid nutrient medium DKW for introduction into the culture and cultivation of walnut (Juglans regia) in vitro is recommended to increase the survival rate of explants by 20%, as well as the accelerated activation of buds (2 days) and their further proliferation.

Altered volatile emission of pear trees under elevated atmospheric CO2 levels has no relevance to pear psyllid host choice

The impact of climate change drivers on cultivated plants and pest insects has come into research focus. One of the most significant drivers is atmospheric carbon dioxide, which is converted into primary plant metabolites by photosynthesis. Increased atmospheric CO2 concentrations therefore affect plant chemistry. The chemical composition of non-volatile and volatile organic compounds of plants is used by insects to locate and identify suitable host plants for feeding and reproduction. We investigated whether elevated CO2 concentrations in the atmosphere affect the plant-pest interaction in a fruit crop of high economic importance in Europe. Therefore, potted pear trees were cultivated under specified CO2 conditions in a Free-Air Carbon dioxide Enrichment (FACE) facility at Geisenheim University in Germany for up to 14 weeks, beginning from bud swelling. We compared emitted volatiles from these pear trees cultivated for 7 and 14 weeks under two different CO2 levels (ambient: ca. 400 ppm and elevated: ca. 450 ppm CO2) and their impact on pest insect behavior. In total, we detected and analyzed 76 VOCs from pear trees. While we did not detect an overall change in VOC compositions, the relative release of single compounds changed in response to CO2 increase. Differences in VOC release were inconsistent over time (phenology stages) and between study years, indicating interactions with other climate parameters, such as temperature. Even though insect-plant interaction can rely on specific volatile compounds and specific mixtures of compounds, respectively, the changes of VOC patterns in our field study did not impact the host choice behavior of C. pyri females. In olfactometer trials, 64% and 60% of the females preferred the odor of pear trees cultivated under elevated CO2 for 7 and 14 weeks, respectively, over the odor from pear trees cultivated under ambient CO2. In binary-choice oviposition assays, C. pyri females laid most eggs on pears during April 2020; on average, 51.9 (± 51.3) eggs were laid on pears cultivated under eCO2 and 60.3 (± 48.7) eggs on aCO2.

Spatial patterns and climatic drivers of leaf spring phenology of maple in eastern North America

The resurgent frequency of extreme weather events and their strongly distinctive spatial patterns lead to a growing interest in phenology as an indicator of tree susceptibility. Using a long-term chronology of observations collected in situ, we predicted and investigated the spatial patterns and environmental drivers of spring leaf phenology across maple stand polygons dominated by Acer saccharum Marsh. and/or Acer rubra L. in eastern North America for 2000-2018. Model' calibration was based on Bayesian ordinal regressions relating the timing of the phenological events' observations to the MODIS vegetation indices EVI, NDVI and LAI. DAYMET data have been extracted to compute temperature and precipitation during spring phenology. Model accuracy increased as the season progressed, with prediction uncertainty spanning from 9 days for bud swelling to 4 days for leaf unfolding. NDVI and LAI were the best predictors for the onset and ending of spring phenology, respectively. Bud swelling occurred at the end of March in the early stands and at the onset of May in the late stands, while leaf unfolding was completed at the beginning of April for the early and in mid-June for the late stands. Early and late stands polarized towards a south-west-north-east gradient. In the south-western regions, which are also the driest, total precipitation and minimum temperature explained respectively 73 % and 25 % of the duration of spring phenology. In the north-eastern regions, precipitation and minimum temperature explained 62 % and 26 % of the duration of spring phenology. Our results suggest high vulnerability to extreme weather events in stands located in the south-west of the species distribution. The increasing incidence of drought in these locations might affect spring phenology, decreasing net primary production in these stands. Warmer nights might expose the buds to late frosts, events that are expected to become more frequent in the coming years.

The seasonal progression of the reproductive phenology of two southern highbush blueberry (V. corymbosum L. interspecific hybrids) cultivars in the Western Cape, South Africa

• The reproductive phenology of SHB cultivars ‘8-42’ and ‘9-02’ was documented for the first time in such depth and per whole plant. • The timing and peaks of the phenological stages quantified on individual plant basis were similar between the two locations - for both cultivars. • The duration of the phenological stages was influenced by micro climate. • The intensity of bud development was accurately illustrated per cultivar and location. • The differences in the intensity of phenological development on bud and plant level will serve as baseline for further studies on carbohydrate allocation to explain the differences in yield. The objective of this study was to evaluate the timing and duration of selected flower bud phenological stages of two southern highbush blueberry (SHB) cultivars in a Mediterranean climate to optimize the management of commercial production systems. The experiment was conducted in commercial orchards during the 2020 growing season, in the Hex River and Wolseley production areas, Western Cape, South Africa. The timing (date) and duration (days) of selected flower bud stages were recorded on individual plants, from April to November 2020 for bud swell, bud break, tight cluster, closed flower, open flower, petal fall, green fruit, colouring fruit, and fruit harvest respectively. Standard commercial management practices were followed on both sites. Cultivar 8-42 flowered from April to mid-October, with a peak during early August. Cropping occurred from early August to mid-November, and volumes peaked in October, at both sites. Cultivar 9-02 flowered from April to late October, with a peak during early August at the Wolseley site, whereas flowering for this cultivar only peaked during late September, at the Hex River site, indicating a possible climate related response. Subsequently, harvest started two weeks later at the Hex River site for ‘9-02’, while the highest yield volumes were obtained during October to early November, at both sites. This paper provides a first report on the phenological categorization of the reproductive development of commercial SHB blueberry cultivars, as produced in the Western Cape, South Africa. As all major management decisions in blueberry cultivation depend on the phenological phases of the crop, this information will contribute towards decision making regarding production, but also via quantifying the progression of each stage in addition to the peaks, allowing for additional logistical management. The influence of growing conditions on the phenological development of these cultivars was also explored and indicated the need for supplemental research considering the influence of micro-environmental conditions in driving evergreen production blueberry systems.

CHANGES IN SPRING PHENOLOGY IN APPLE TREE AND ITS RESISTANCE TO LATE FROST UNDER THE CLIMATE CONDITIONS OF STANESTI AREA, ARGES COUNTY, ROMANIA

This paper aimed to analyze the variability of spring phenophases in the apple species, the ‘GoldRush’ cultivar to analyze the risk of spring frost for apple production in Stănești area of Argeș County (45°13′44″N, 24°50′9″E, altitude 540m), Romania, and the role of phenological acclimatization. The timing of phenological stages is made according to the definitions of the Biologische Bundesanstalt, Bundessortenamt, and CHemical industry (BBCH). Based on Julian day number, on average for 4 years, the phenophases occurred from the 85.54 day of year, marked by “beginning of leaf bud swelling/inflorescence bud swelling” (BBCH 01/51), until 1the 23.36 day of year for phenophase ''end of flowering'' (BBCH 69). Analyzing the data obtained, they allowed us to assess the temporal trends of development of budding and flowering phenophases and the trends of risks in the light of global warming. The research will be continued in order to analyze a longer period of time and to analyze different cultivars, in order to achieve sustainable and competitive fruit crops.

Effects of warming, photoperiod, and nitrogen addition on the main phenological phases of Quercus mongolica

With a large artificial climate chamber, we examined the effects of warming (control, +1.5 ℃, +2.0 ℃), photoperiod (10, 14, 18 h) and nitrogen addition (0, 5, 10, 20 g N·m-2·a-1) on the main phenological phases of Quercus mongolica in Northeast China. The results showed that 1.5 and 2.0 ℃ warming significantly advanced the bud swelling stage and delayed the leaf fully coloring stage, which prolonged the growing season. The extended days increased with the increases of warming range. Photoperiod significantly affected autumn phenology (leaf coloration onset stage, leaf coloration in general stage, leaf fully coloring stage). Compared with photoperiod of 14 h, short photoperiod (10 h) significantly delayed leaf coloration onset stage by 7.0 d, and prolonged the peak of growth season. Nitrogen addition significantly advanced the bud swelling stage, bud opening stage, first leaf unfolding stage and full leaf unfolding stage. The leaf fully coloring stage was significantly delayed by 9.5 d only at the high nitrogen level of 20 g N·m-2·a-1, indicating that high nitrogen addition prolonged the growing season of Q. mongolica. The synergistic effects of warming and high nitrogen addition (20 g N·m-2·a-1) significantly delayed the leaf fully coloring stage, which prolonged leaf coloration stage, and the synergistic effects of warming and short photoperiod, the synergistic effects of nitrogen addition and short photoperiod. The synergistic effects of warming, nitrogen addition and short photoperiod all significantly delayed the leaf coloration onset stage, which relatively prolonged the peak of growing season.

Influence of Climate Change on the Phenological Stages at the Sour Cherry Genotypes

The present study establishes the influence of changes in climatic conditions on the development of ten sour cherry cultivars existing in the sour cherry germplasm fund from Research Station for Fruit Growing Iaşi, Romania. The first four phenological stages were taken in account: bud swelling (code 51 BBCH), bud burst (code 53), beginning of flowering (code 61) and end of flowering (code 69) over three different periods of time (2006-2008, 2009-2011 and 2019-2021). Were registered the number of days, the sum of active temperature (SAT), growing degree-days (GDD) as well as the correlation coefficient between the number of days and the sum of active temperature between phenological developmental stages, buds swelling and bud burst, bud burst and beginning of flowering and from beginning of flowering to the end of flowering. The results obtained in the three time periods (from 2006 to 2021) have statistically significant differences and were recorded especially at the phenophases of flowering. The study determined that the higher annual average temperature was (from 10.45℃ to 11.69℃), the more significant were the statistically differences. Thereby, phenological changes were a reaction to temperature what can be assumed also with the results of the present study.

The Influence of Variety and Climatic Year on the Phenology of Blueberry Grown in the Banat Area, Romania

This paper’s aim was to investigate the influence of variety and the climatic year on vegetation phenophases in blueberries grown in southwest Romania, the Banat region. This study was carried out during the growing season of 2020–2022 in a blueberry plantation, for ‘Duke’, ‘Hannah’s Choice’ and ‘Elliott’ varieties. In the study, phenological traits were recorded using the BBCH phenological scale and the observation of phenotypic data was recorded as in Julian days. Thus, it is found that the duration of each phenophase characterized each variety. The calendar periods for the onset of vegetation and the duration of spring phenological development stages in varieties have differed from year to year and depended on weather conditions. In the case of the phenological stage, depending on variety, the maximum amplitude was recorded for BBCH 87 stage (75% blue fruits) of 51 days, and the minimum amplitude, of 25 days, for BBCH 51 stage (bud swell) and BBCH 59 (late pink bud). The coefficient of variation, depending on climatic year, for generative phenophases, had values between 6.5% (BBCH 67-petal fall) and 21.1% (BBCH 51-bud swell). It was found that the variety and the climatic year influence the development of vegetation phenophases. The results indicate that blueberry cultivars have demonstrated a high degree of phenotypic plasticity to respond to gradual changes in environmental conditions and are important for the evaluation of cultivar cultivation prospects in the studied area.