Dormancy Phase Research Articles

Temporal changes in the proanthocyanidins to anthocyanins ratio during dormancy associate with bloom time variations in peach

Our previous research demonstrated that fall applications of ethephon, an ethylene-releasing plant growth regulator, delay bloom in peach, accompanied by changes in endogenous hormones, ROS, sugar metabolism, and transcriptomic profiles during bud dormancy phases (endodormancy and ecodormancy). In this study, floral bud tissues were collected from ethephon-treated and untreated trees at three time points (200, 600, and 1000 chilling hours, CH) during endodormancy and two points (1000 and 3000 growing degree hours, GDH) during ecodormancy. Using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF/MS), we aimed to unravel the untargeted metabolic changes explaining ethephon-mediated bloom delay. Metabolite set-enrichment analysis (MSEA) revealed significant chemical group variations between dormancy phases, with a threefold increase in flavonoids during endodormancy and a doubling of organic and amino acids during ecodormancy. Further analysis of genes associated with the biosynthesis and transcriptional regulation of the flavonoid pathway showed that ethephon treatment upregulated genes associated with proanthocyanidin (PA) biosynthesis and downregulated genes related to anthocyanins (ACNs). We quantified PA and ACN contents in 12 peach cultivars with contrasting bloom times and chilling requirements (e.g. 727–1308 CH). Late-bloom cultivars had higher PA levels during endodormancy, while early-bloom cultivars had higher ACN levels during ecodormancy. Staining buds with 4-dimethylaminocinnamaldehyde (DMAC) dye revealed a decline in the PA/ACN ratio at later ecodormancy stages, correlating with bloom time. Integrated analysis of metabolite content and gene expression in late-bloom 'KV021779' and early-bloom 'John Boy' cultivars validated that late-blooming cultivars have higher PA levels during endodormancy, extending dormancy-release periods and resulting in later blooms.

Dormancy regulator Prunus mume DAM6 promotes ethylene-mediated leaf senescence and abscission.

Leaf senescence and abscission in autumn are critical phenological events in deciduous woody perennials. After leaf fall, dormant buds remain on deciduous woody perennials, which then enter a winter dormancy phase. Thus, leaf fall is widely believed to be linked to the onset of dormancy. In Rosaceae fruit trees, DORMANCY-ASSOCIATED MADS-box (DAM) transcription factors control bud dormancy. However, apart from their regulatory effects on bud dormancy, the biological functions of DAMs have not been thoroughly characterized. In this study, we revealed a novel DAM function influencing leaf senescence and abscission in autumn. In Prunus mume, PmDAM6 expression was gradually up-regulated in leaves during autumn toward leaf fall. Our comparative transcriptome analysis using two RNA-seq datasets for the leaves of transgenic plants overexpressing PmDAM6 and peach (Prunus persica) DAM6 (PpeDAM6) indicated Prunus DAM6 may up-regulate the expression of genes involved in ethylene biosynthesis and signaling as well as leaf abscission. Significant increases in 1-aminocyclopropane-1-carboxylate accumulation and ethylene emission in DEX-treated 35S:PmDAM6-GR leaves reflect the inductive effect of PmDAM6 on ethylene biosynthesis. Additionally, ethephon treatments promoted autumn leaf senescence and abscission in apple and P. mume, mirroring the changes due to PmDAM6 overexpression. Collectively, these findings suggest that PmDAM6 may induce ethylene emission from leaves, thereby promoting leaf senescence and abscission. This study clarified the effects of Prunus DAM6 on autumn leaf fall, which is associated with bud dormancy onset. Accordingly, in Rosaceae, DAMs may play multiple important roles affecting whole plant growth during the tree dormancy induction phase.

Identifying indicators of apple bud dormancy status by exposure to artificial forcing conditions.

Dormancy in temperate fruit trees is a mechanism of temporary growth suspension, which is vital for tree survival during winter. Studies on this phenomenon frequently employ scientific methods that aim to detect the timing of dormancy release. Dormancy release occurs when trees have been exposed to sufficient chill, allowing them to resume growth under conducive conditions. This study investigates dormancy dynamics in two apple (Malus × domestica Borkh.) cultivars, 'Nicoter' and 'Topaz', by sampling branches in an orchard over 14weeks (2019 to 2020) and over 31weeks (2021 to 2022) and subjecting them to a 42-day budbreak forcing period in a growth chamber. Temporal changes in budbreak percentages demonstrated dormancy progression in the studied apple cultivars and allowed the three main dormancy phases to be distinguished: paradormancy (summer dormancy), endodormancy (deep dormancy) and ecodormancy (spring dormancy), along with transition periods between them. Using these data, we explored the suitability of several alternative methods to determine endodormancy release. Tabuenca's test, which predicts dormancy release based on the differences in dry weights of buds with and without forcing, showed promise for this purpose. However, our data indicated a need for considerable adjustments and validation of this test. Bud weight and water content of buds in the orchard did not align with budbreak percentages under forcing conditions, rendering them unsuitable for determining endodormancy release in 'Nicoter' and 'Topaz'. Shoot growth cessation did not seem to be connected with either dormancy progression or dormancy depth of the studied cultivars, whereas leaf fall coincided with the beginning of the transition from endo- to ecodormancy. This work addresses methodological limitations in dormancy research and suggests considering the mean time to budbreak and budbreak synchrony as additional criteria to assess tree dormancy status.

A new perspective on tree growing season determination

AbstractDefining plant development timing through seasonal growth and dormancy phases is a valuable proxy for studying climate change and serves as an annual bioindicator. However, current methods for determining the growing season vary due to species‐specific interpretations and differing understandings of its main drivers. Körner et al. (2023) introduced four non‐interchangeable definitions of growing seasons to clarify this complex issue. While some studies have paired different methods, none have simultaneously applied a full set of methods at the individual tree or species level. Here, I aim to present a new perspective to understanding growing season timing by focusing on all facets of above‐ground tree growth and measurable biological and phenological markers. This approach calls for simultaneous, continuous monitoring during active and dormancy periods on the same trees and across different species at a large spatial scale. The goal is to comprehensively understand each method's errors, temporal lags, and the factors determining each growing season, as defined by Körner et al. (2023, Ecology Letters, 26, 1277). Accurate estimation of growing season timing can reshape our understanding of its environmental drivers, improve terrestrial ecosystem models, assess the impact of climate change on tree growth, determine the biological zero for various species, verify remote sensing indices and forecast species distribution.

How Can Seasonality Influence the Performance of Recent Microwave Satellite Soil Moisture Products?

In addition to technical issues related to the instruments used, differences between soil moisture (SM) measured using ground-based methods and microwave remote sensing (RS) can be related to the main features of the study areas, which are intricately connected to hydraulic–hydrological conditions and soil properties. When long-term analysis is performed, these discrepancies are mitigated by the contribution of SM seasonality and are only evident when high-frequency variations (i.e., signal anomalies) are investigated. This study sought to examine the responsiveness of SM to seasonal variations in terrestrial ecoregions located in areas covered by the in situ Romanian Soil Moisture Network (RSMN). To achieve this aim, several remote sensing-derived retrievals were considered: (i) NASA’s Soil Moisture Active and Passive (SMAP) L4 V5 model assimilated product data; (ii) the European Space Agency’s Soil Moisture and Ocean Salinity INRA–CESBIO (SMOS-IC) V2.0 data; (iii) time-series data extracted from the H115 and H116 SM products, which are derived from the analysis of Advanced Scatterometer (ASCAT) data acquired via MetOp satellites; (iv) Copernicus Global Land Service SSM 1 km data; and (v) the “combined” European Space Agency’s Climate Change Initiative for Soil Moisture (ESA CCI SM) product v06.1. An initial assessment of the performance of these products was conducted by checking the anomaly of long-term fluctuations, quantified using the Absolute Variation of Local Change of Environment (ALICE) index, within a time frame spanning 2015 to 2020. These correlations were then compared with those based on raw data and anomalies computed using a moving window of 35 days. Prominent correlations were observed with the SMAP L4 dataset and across all ecoregions, and the Balkan mixed forests (646) exhibited strong concordance regardless of the satellite source (with a correlation coefficient RALICE > 0.5). In contrast, neither the Central European mixed forests (No. 654) nor the Pontic steppe (No. 735) were adequately characterized by any satellite dataset (RALICE < 0.5). Subsequently, the phenological seasonality and dynamic behavior of SM were computed to investigate the effects of the wetting and drying processes. Notably, the Central European mixed forests (654) underwent an extended dry phase (with an extremely low p-value of 2.20 × 10−16) during both the growth and dormancy phases. This finding explains why the RSMN showcases divergent behavior and underscores why no satellite dataset can effectively capture the complexities of the ecoregions covered by this in situ SM network.

Helix salomonica Nägele, 1899 (Gastropoda: Helicidae): annual activity cycles in its natural habitat in southeastern Turkey

ABSTRACT This research focused on the annual activities, including aestivation, hibernation and reproductive behaviours, of the endemic species Helix salomonica Nägele, 1899 in its natural habitat in Şırnak, Turkey. Within an area of 900 m2, a population of at least 600 snails was monitored for a year. Eighty snail specimens were sampled and measured, with twenty of them observed in a laboratory environment (within a cage) for comparison of circannual snail rhythms. The annual activity patterns of H. salomonica revealed distinctive behaviours. The total hibernation period lasted around 85 days on average, with continuous hibernation lasting approximately 57 days and intermittent hibernation lasting about 28 days. In March and November, copulation occurs. Durıng the sprıng,the average number of eggs was 63, with an average diameter of 2.85 mm and a weight of 0.28 g. On average, eggs hatched after 34 days, during the second and third weeks of May. Aestivation persisted continuously from late May to early November, averaging 165 days. Arousal and the observation of juvenile snails coincided in the second week of November. Consequently, the annual activity cycles of H. salomonica are intricately regulated by a complex interplay of internal (endogenous) rhythms and external factors, with dormancy phases predominantly governed by circannual rhythms.

Genetic and molecular regulation of chilling requirements in pear: breeding for climate change resilience.

Pear (Pyrus spp.) is a deciduous fruit tree that requires exposure to sufficient chilling hours during the winter to establish dormancy, followed by favorable heat conditions during the spring for normal vegetative and floral budbreak. In contrast to most temperate woody species, apples and pears of the Rosaceae family are insensitive to photoperiod, and low temperature is the major factor that induces growth cessation and dormancy. Most European pear (Pyrus Communis L.) cultivars need to be grown in regions with high chilling unit (CU) accumulation to ensure early vegetative budbreak. Adequate vegetative budbreak time will ensure suitable metabolite accumulation, such as sugars, to support fruit set and vegetative development, providing the necessary metabolites for optimal fruit set and development. Many regions that were suitable for pear production suffer from a reduction in CU accumulation. According to climate prediction models, many temperate regions currently suitable for pear cultivation will experience a similar accumulation of CUs as observed in Mediterranean regions. Consequently, the Mediterranean region can serve as a suitable location for conducting pear breeding trials aimed at developing cultivars that will thrive in temperate regions in the decades to come. Due to recent climatic changes, bud dormancy attracts more attention, and several studies have been carried out aiming to discover the genetic and physiological factors associated with dormancy in deciduous fruit trees, including pears, along with their related biosynthetic pathways. In this review, current knowledge of the genetic mechanisms associated with bud dormancy in European pear and other Pyrus species is summarized, along with metabolites and physiological factors affecting dormancy establishment and release and chilling requirement determination. The genetic and physiological insights gained into the factors regulating pear dormancy phase transition and determining chilling requirements can accelerate the development of new pear cultivars better suited to both current and predicted future climatic conditions.

Dynamic Protein Phosphorylation in Streptococcus pyogenes during Growth, Stationary Phase, and Starvation.

Phosphorylation of proteins at serine, threonine, and tyrosine residues plays an important role in physiological processes of bacteria, such as cell cycle, metabolism, virulence, dormancy, and stationary phase functions. Little is known about the targets and dynamics of protein phosphorylation in Streptococcus pyogenes, which possesses a single known transmembrane serine/threonine kinase belonging to the class of PASTA kinases. A proteomics and phosphoproteomics workflow was performed with S. pyogenes serotype M49 under different growth conditions, stationary phase, and starvation. The quantitative analysis of dynamic phosphorylation, which included a subset of 463 out of 815 identified phosphorylation sites, revealed two main types of phosphorylation events. A small group of phosphorylation events occurred almost exclusively at threonine residues of proteins related to the cell cycle and was enhanced in growing cells. The majority of phosphorylation events occurred during stationary phase or starvation, preferentially at serine residues. PASTA kinase-dependent cell cycle regulation processes found in related bacteria are conserved in S. pyogenes. Increased protein phosphorylation during the stationary phase has also been described for some other bacteria, and could therefore be a general feature in the physiology of bacteria, whose functions and the kinases involved need to be elucidated in further analyses.

Evaluation of Fall and Winter Trinexapac-ethyl Applications on Ultradwarf Bermudagrass Putting Green Color, Quality, and Green Cover

Ultradwarf bermudagrass (UDB) putting greens grown in subtropical and temperate climates can face elevated risk of winter injury from cold temperatures. Trinexapac-ethyl (TE) inhibits UDB growth potentially reducing spring green-up and overexertion of carbohydrate reserves for UDB during the cold de-acclimation period. A field study was conducted to determine the effect of fall and winter TE applications on the visual quality and color of UDB putting greens in Virginia from the cold acclimation phase through the cold de-acclimation phase. A second controlled-environment study was conducted to determine how TE applications to UDB during cold acclimation affected UDB cold tolerance. In the first study, plots were treated with 0.026 kg⋅ha−1 a.i. every 14 days, 0.013 kg⋅ha−1 a.i. every 14 days, or 0.013 kg⋅ha−1 a.i. every 7 days either in the fall only or in the fall and winter. A nontreated control was included for comparison. For the second study, cup-cutter plugs (10.8-cm diameter) of UDB were treated with 0.026 kg⋅ha−1 a.i. every 14 days from the time growth resumed after green-up through cold acclimation or not treated with TE. Plugs were then exposed to −9.4 °C for 4, 6, 8, or 10 hours and placed into a greenhouse to green up. The GC50 values (exposure time to reduce bermudagrass green cover by 50% 6 days after exposure to −9.4 °C) for the treatments were then calculated based on exposure time and percent green-up. In the first study, TE applications improved UDB quality >3.8%. However, TE applications reduced UDB color, and trends exhibited this reduction in color particularly during the late cold acclimation, winter dormancy, and early cold de-acclimation phases. In the second study, TE applications reduced GC50 values by >10.9% compared with nontreated plugs, suggesting TE reduces UDB cold tolerance during the cold acclimation phase.

Screening and Expression Analysis of POD Gene in POD-H2O2 Pathway on Bud Dormancy of Pear (Pyrus pyrifolia)

Bud endodormancy represents a pivotal and intricate biological process influenced by both genetic and epigenetic factors, the exact mechanism of which remains elusive. Hydrogen peroxide (H2O2) functions as a signalling molecule in the regulation of dormancy, with peroxidase (POD) playing a crucial role in governing H2O2 levels. Our prior transcriptomic and metabolomic investigations into diverse pear dormancy phases posited that POD predominantly oversees pear bud dormancy. In this study, we utilised qRT-PCR to screen the most significantly expressed gene, Pyrus pyrifolia POD4-like (PpPOD4-like), from seven POD genes. Subsequently, H2O2 test kits, overexpression methods, and subcellular localisation techniques were employed to assess changes in H2O2 content, POD activity, PpPOD4-like expression, and its cellular positioning during pear bud dormancy. Subcellular localisation experiments revealed that PpPOD4-like is situated on the cell membranes. Notably, H2O2 content exhibited a rapid increase during endodormancy and decreased swiftly after ecodormancy. The fluctuation pattern of POD activity aligned with that of H2O2 content. Additionally, PpPOD4-like expression was markedly upregulated, displaying an overall upward trajectory. Our findings indicate that PpPOD4-like modulates H2O2 levels by regulating POD activity, thereby actively participating in the intricate regulation of pear dormancy processes.

Warming increases the differences among spring phenology models under future climate change.

Phenological models are built upon an understanding of the influence of environmental factors on plant phenology, and serve as effective tools for predicting plant phenological changes. However, the differences in phenological model predictive performance under different climate change scenarios have been rarely studied. In this study, we parameterized thirteen spring phenology models, including six one-phase models and seven two-phase models, by combining phenological observations and meteorological data. Using climatic data from two Shared Socioeconomic Pathways (SSP) scenarios, namely SSP126 (high mitigation and low emission) and SSP585 (no mitigation and high emission), we predicted spring phenology in Germany from 2021 to 2100, and compared the impacts of dormancy phases and driving factors on model predictive performance. The results showed that the average correlation coefficient between the predicted start of growing season (SOS) by the 13 models and the observed values exceeded 0.72, with the highest reaching 0.80. All models outperformed the NULL model (Mean of SOS), and the M1 model (driven by photoperiod and forcing temperature) performed the best for all the tree species. In the SSP126 scenario, the average SOS advanced initially and then gradually shifted towards a delay starting around 2070. In the SSP585 scenario, the average SOS advanced gradually at a rate of approximately 0.14 days per year. Moreover, the standard deviation of the simulated SOS by the 13 spring phenology models exhibited a significant increase at a rate of 0.04 days per year. On average, two-phase models exhibited larger standard deviations than one-phase models after approximately 2050. Models driven solely by temperature showed larger standard deviations after 2060 compared to models driven by both temperature and photoperiod. Our findings suggest investigating the release mechanisms of endodormancy phase and incorporating new insights into future phenological models to better simulate the changes in plant phenology.

Optimized differential thermal analysis sheds light on the effect of temperature on peach floral bud cold hardiness and transition from endo- to ecodormancy

The greatest threat to profitable peach production is cold damage to reproductive tissues. To better understand and mitigate cold damage in peach accurate and efficient assessment of floral bud cold hardiness (Hc) is critical. Differential thermal analysis (DTA) was optimized for efficient and precise detection of low-temperature exotherms (LTE) created by the freezing of supercooled intracellular water in peach floral primordia to determine Hc weekly during the dormant season. DTA-estimated lethal temperatures (LT) were validated against the standard oxidative browning method (OB) and in situ field damage following three freezing events. Chilling (0–7.2 °C) accumulation tracked throughout the dormant season to determine DTA-related changes across dormancy phase transitions. LTEs showed rapid acclimation of ‘Redhaven’ peach floral buds following the first frost of the dormant season (Tmin=−6.8 °C on November 18, 2016) and maintained similar Hc levels for 45 days through maximum Hc (LT50 =−23.9 °C recorded on January 9, 2017) and until the accumulation of 868 chilling hours was reached. Following this milestone, a significant 55% loss of LTEs upon the accumulation of the first growing degree day (Tbase=7 °C) was recoded on February 7, 2017. An LTE recovery approach, pre-exposing buds to a non-freezing low temperature (−2°C) for a period of 12 h, more than doubled the number of LTEs detected for another 27 days extending DTA use for LT prediction. The results presented herein confirm that the use of DTA is efficient and accurate to determine Hc in peach floral buds, and suggest that the LTE loss in early spring may be a signature response related to the shift from endo- into ecodormancy following two environmental temperature cues, chilling satisfaction and the first heat accumulation post chilling satisfaction.

Flocking Control for Cucker–Smale Model Subject to Denial-of-Service Attacks and Communication Delays

This paper examines the flocking control issue of the Cucker–Smale model in the presence of denial-of-service (DoS) attacks and communication delays. In the setting of DoS attacks, the attacker only obstructs the information communication between agents during the activation phases, while it concentrates on supplying its own energy during the dormancy phases. Furthermore, the communication delays are assumed to be time-varying and heterogeneous. Firstly, a general control input scheme that defends against DoS network attacks and communication delays is constructed. Secondly, on the basis of the presented control input and the properties of graph theory, the flocking control issue is equivalently transformed into a products convergence issue of infinite sub-stochastic matrices. Finally, an algebraic condition is obtained to formulate all the agents that asymptotically achieve the flocking behavior. Moreover, the obtained theoretical results are verified by a numerical example.

What Is Wrong with Winter Chill Models in Warm Climates?

Bud dormancy is an evolutionary strategy that protects temperate fruit trees from low temperatures during winter. With adequate winter chilling, it is a process consisting of a rapid entrance phase where growth inhibition increases to a maximum and is then released via an exit phase. This progression is, however, different in areas with insufficient winter chill. In such areas, the dormancy entrance phase is protracted, and the exit phase is often incomplete. Several chill models have been designed to describe the plants’ response to chill accumulation to match cultivar and site. Although it is known that these models are less accurate in warm winter areas, their accuracy during the two dormancy phases has always been assumed equal. The aim of this study was to investigate the accuracy of four chill models during the entrance and exit phases of bud dormancy of ‘Royal Gala’ buds from two contrasting climatic areas. One-year-old shoots were collected from commercial orchards and forced to determine their bud dormancy level. Before forcing, the shoots received varied amounts of chill additional to the field chill. The bud dormancy progression was represented as joint two- or three-line models to determine the entrance and exit phases. For each phase, the dormancy level of every sample was plotted against its chill accumulation based on four chill models (Chilling Hours, Utah, Positive Utah, and Dynamic Model). Results were compared to determine the ability of each model to predict the linearity of the dormancy progression. The results indicated that although all the models were able to describe the exit phase of bud dormancy successfully, none could describe a linear entrance phase. This suggests that during the onset of dormancy, buds respond to temperature differently to what is measured by the chill models making the models unreliable when winter chill is inadequate.

Industrial-scale for hydrogen charging in activated carbon (AX-21)-phase change material-nano-oxides systems

As a plausible solution for the issue of heat management during hydrogen adsorption on the activated carbon bed, in the present paper, the effects of different metal oxides nanoparticles (MgO, TiO2, CuO, or ZnO), scattered into a phase change material (PCM), have been investigated over the adsorption and dormancy phases in a large-scale bottle. This study has been conducted using Fluent software, in which a computational fluid dynamics (CFD) model (based on finite volume simulations) was implemented. This model has been validated via the experimental and theoretical results available in literature. Throughout the duration of the charging process, it has been found that the presence of nanoparticles in PCM body does not affect the thermal performance of the solid bed of activated carbon,. However, the melt fraction of PCM is steeply increased to 20 % in the range ~ 0–1300 s, whereas over 1300 s, the melting process of paraffin is amortized until the end of the dormancy phase (attaining ~ 30–35 % of liquid PCM). This trend is observed either in the presence or in the absence of metal oxides, where 16 % of enhancement in the liquid fraction of PCM is retrieved in the presence of nanoparticles (5 %) at the end of the dormancy phase (10,000 s). As a result, The nano-PCM system could be a proposed pathway for recovering the heat generated from the H2 adsorption and then replacing the fluid cooling system (cost). However, it was recommended that future research works should be focused on the improvement of the solid bed thermal conductivity in addition to the enhancement of the reactor geometry via new innovative solution pathways.

Metabolites That Confirm Induction and Release of Dormancy Phases in Sweet Cherry Buds

Here we report on metabolites found in a targeted profiling of 'Summit' flower buds for nine years, which could be indicators for the timing of endodormancy release (t1) and beginning of ontogenetic development (t1*). Investigated metabolites included chrysin, arabonic acid, pentose acid, sucrose, abscisic acid (ABA), and abscisic acid glucose ester (ABA-GE). Chrysin and water content showed an almost parallel course between leaf fall and t1*. After 'swollen bud', water content raised from ~60 to ~80% at open cluster, while chrysin content decreased and lost its function as an acetylcholinesterase inhibitor. Both parameters can be suitable indicators for t1*. Arabonic acid showed a clear increase after t1*. Pentose acid would be a suitable metabolite to identify t1 and t1*, but would not allow describing the ecodormancy phase, because of its continuously low value during this time. Sucrose reached a maximum during ecodormancy and showed a significant correlation with air temperature, which confirms its cryoprotective role in this phase. The ABA content showed maximum values during endodormancy and decreased during ecodormancy, reaching 50% of its content t1 at t1*. It appears to be the key metabolite to define the ecodormancy phase. The ABA-GE was present at all stages and phases and was much higher than the ABA content and is a readily available storage pool in cherry buds.

Pregnancy length and health in giant pandas: What can metabolic and urinary endocrine markers unveil?

Mature female giant pandas usually ovulate once a year. This is followed by an obligatory luteal phase, consisting of a long-lasting corpus luteum dormancy phase (CLD; primary increase in progestogens) and a much shorter active luteal phase (AL; secondary increase in progestogens). Varying duration of both the dormant (embryonic diapause) and AL (post-embryo reactivation) phases has hampered unambiguous pregnancy length determination in giant pandas until today. Additionally, progestogen profiles have been considered not to differ between pregnant and pseudopregnant cycles. Only ceruloplasmin, 13,14-dihydro-15-keto-PGF2α (PGFM) and – more recently – estrogens have been assigned diagnostic power so far. Our study investigated the competence of metabolic (fecal output) and Urinary Specific Gravity (USpG)-normalized urinary endocrine (progestogens, PGFM, glucocorticoids (GCM) and ceruloplasmin) markers for pregnancy monitoring including defining the duration of the AL phase length. Research on 24 (6 pregnant, 8 pseudopregnant and 10 non-birth) cycles of 6 giant pandas revealed a fixed AL phase length of 42 days in giant pandas, e.g. representing 6 weeks of post- diapause development in case of pregnancy. Progestogen concentrations were significantly higher in pregnant cycles throughout the majority of the AL phase, with significant higher values during the AL phase in healthy twin compared to singleton pregnancies. GCM concentrations were also markedly higher in giant pandas expecting offspring, with a clear increase towards birth in the final 2 weeks of pregnancy. This increase in GCM was running in parallel with elevating estrogen and PGFM concentrations, and decreasing progestogens. In addition, during the AL phase, a more pronounced decrease in fecal output was obvious for pregnant females. The combined profiles of non-invasive metabolic and endocrine markers, the latter normalized based on USpG, showed a true pregnancy signature during the AL phase. The findings of this study are applicable to retrospective evaluations of non-birth cycles facilitating categorizing those into pseudopregnant or lost pregnancies, with USpG-normalization of the urinary endocrine markers as a prerequisite.

Coping strategy of porang farmer’s household in anticipating long harvest period: Empirical study in Wonogiri Regency, Indonesia

Porang is one of the alternative foods commonly cultivated in several areas, including Wonogiri Regency, because this area is suitable for its development. The cultivation business is not devoid of challenges. The tubers of Porang experience a dormancy phase, resulting in a long growing period of 6 to 10 months. Therefore, this study aims to identify the coping strategies used by farmers to adapt the length of the porang harvest period. Furthermore, this study is qualitative in nature involving 180 farmers selected through a census. The snowball sampling method was used to select respondents from 6 sub-districts in Wonogiri Regency in Indonesia. Furthermore, the analysis was conducted descriptively using an index coping strategy for measurement. These results indicated that farmers employ 11 types of coping strategies. The application is performed by combining one type up with more than 4 others. Most of the coping strategies types are applied to 2 combinations, hence, its index is in a low category. The alternative is a realistic combination that farmers can choose based on human and other resource availability.

Non-Invasive Probing of Winter Dormancy via Time-Frequency Analysis of Induced Chlorophyll Fluorescence in Deciduous Plants as Exemplified by Apple (Malus × domestica Borkh.).

Dormancy is a physiological state that confers winter hardiness to and orchestrates phenological phase progression in temperate perennial plants. Weather fluctuations caused by climate change increasingly disturb dormancy onset and release in plants including tree crops, causing aberrant growth, flowering and fruiting. Research in this field suffers from the lack of affordable non-invasive methods for online dormancy monitoring. We propose an automatic framework for low-cost, long-term, scalable dormancy studies in deciduous plants. It is based on continuous sensing of the photosynthetic activity of shoots via pulse-amplitude-modulated chlorophyll fluorescence sensors connected remotely to a data processing system. The resulting high-resolution time series of JIP-test parameters indicative of the responsiveness of the photosynthetic apparatus to environmental stimuli were subjected to frequency-domain analysis. The proposed approach overcomes the variance coming from diurnal changes of insolation and provides hints on the depth of dormancy. Our approach was validated over three seasons in an apple (Malus × domestica Borkh.) orchard by collating the non-invasive estimations with the results of traditional methods (growing of the cuttings obtained from the trees at different phases of dormancy) and the output of chilling requirement models. We discuss the advantages of the proposed monitoring framework such as prompt detection of frost damage along with its potential limitations.

Coffee-Yield Estimation Using High-Resolution Time-Series Satellite Images and Machine Learning

Coffee has high relevance in the Brazilian agricultural scenario, as Brazil is the largest producer and exporter of coffee in the world. Strategies to advance the production of coffee grains involve better understanding its spatial variability along fields. The objectives of this study were to adjust yield-prediction models based on a time series of satellite images and high-density yield data, and to indicate the best phenological stage of coffee crop to obtain satellite images for this purpose. The study was conducted during three seasons (2019, 2020 and 2021) in a commercial area (10.24 ha), located in the state of Minas Gerais, Brazil. Data were obtained using a harvester equipped with a yield monitor that measures the volume of coffee harvested with 3.0 m of spatial resolution. Satellite images from the PlanetScope (PS) platform were used. Random forest (RF) regression and multiple linear regression (MLR) models were fitted to different datasets composed of coffee yield and time series of satellite-image data ((1) Spectral bands—red, green, blue and near-infrared; (2) Normalized difference vegetation index (NDVI); or (3) Green normalized difference vegetation index (GNDVI)). Whether using RF or MLR, the spectral bands, NDVI and GNDVI reproduced the spatial variability of yield maps one year before harvest. This information can be of critical importance for management decisions across the season. For yield quantification, the RF model using spectral bands showed the best results, reaching R2 of 0.93 for the validation set, and the lowest errors of prediction. The most appropriate phenological stage for satellite-image data acquisition was the dormancy phase, observed during the dry season months of July and August. These findings can help to monitor the spatial and temporal variability of the fields and guide management practices based on the premises of precision agriculture.