scholarly journals Effects of the Simulated Enhancement of Precipitation on the Phenology of Nitraria tangutorum under Extremely Dry and Wet Years

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1474
Author(s):  
Fang Bao ◽  
Zhiming Xin ◽  
Jiazhu Li ◽  
Minghu Liu ◽  
Yanli Cao ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Plant Phenology ◽  
Regulation Mechanism ◽  
Arid Areas ◽  
Leaf Fall ◽  
Spring Phenology ◽  
Leaf Unfolding ◽  
Simulated Precipitation ◽  
Leaf Budding ◽  
End Times

Plant phenology is the most sensitive biological indicator that responds to climate change. Many climate models predict that extreme precipitation events will occur frequently in the arid areas of northwest China in the future, with an increase in the quantity and unpredictability of rain. Future changes in precipitation will inevitably have a profound impact on plant phenology in arid areas. A recent study has shown that after the simulated enhancement of precipitation, the end time of the leaf unfolding period of Nitraria tangutorum advanced, and the end time of leaf senescence was delayed. Under extreme climatic conditions, such as extremely dry or wet years, it is unclear whether the influence of the simulated enhancement of precipitation on the phenology of N. tangutorum remains stable. To solve this problem, this study systematically analyzed the effects of the simulated enhancement of precipitation on the start, end and duration of four phenological events of N. tangutorum, including leaf budding, leaf unfolding, leaf senescence and leaf fall under extremely dry and wet conditions. The aim of this study was to clarify the similarities and differences of the effects of the simulated enhancement of precipitation on the start, end and duration of each phenological period of N. tangutorum in an extremely dry and an extremely wet year to reveal the regulatory effect of extremely dry and excessive amounts of precipitation on the phenology of N. tangutorum. (1) After the simulated enhancement of precipitation, the start and end times of the spring phenology (leaf budding and leaf unfolding) of N. tangutorum advanced during an extremely dry and an extremely wet year, but the duration of phenology was shortened during an extremely wet year and prolonged during an extremely drought-stricken year. The amplitude of variation increased with the increase in simulated precipitation. (2) After the simulated enhancement of precipitation, the start and end times of the phenology (leaf senescence and leaf fall) of N. tangutorum during the autumn advanced in an extremely wet year but was delayed during an extremely dry year, and the duration of phenology was prolonged in both extremely dry and wet years. The amplitude of variation increased with the increase in simulated precipitation. (3) The regulation mechanism of extremely dry or wet years on the spring phenology of N. tangutorum lay in the different degree of influence on the start and end times of leaf budding and leaf unfolding. However, the regulation mechanism of extremely dry or wet years on the autumn phenology of N. tangutorum lay in different reasons. Water stress caused by excessive water forced N. tangutorum to start its leaf senescence early during an extremely wet year. In contrast, the alleviation of drought stress after watering during the senescence of N. tangutorum caused a delay in the autumn phenology during an extremely dry year.

scholarly journals Varying Levels of Genetic Control and Phenotypic Plasticity in Timing of Bud Burst, Flower Opening, Leaf Senescence and Leaf Fall in Two Common Gardens of Prunus padus L.

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1070
Author(s):  
Kristine Vander Mijnsbrugge ◽  
Stefaan Moreels
Keyword(s):  
Genetic Control ◽  
Leaf Senescence ◽  
Fine Tuning ◽  
Bud Burst ◽  
Leaf Fall ◽  
Flower Opening ◽  
Growth Environment ◽  
Prunus Padus ◽  
Common Gardens ◽  
Genetic Components

Several phenological phases mark the seasonal growth pattern in temperate woody perennials. To gain further insight into the way these phases react on an altering growth environment, we tested whether vegetative and reproductive phenophases in a shrub species respond differentially among different genetic entities and between two different planting sites. We scored leaf bud burst, flower opening, leaf senescence and leaf fall on 267 ramets of Prunus padus L. belonging to 53 genotypes that were sampled in 9 local populations, and that were planted in 2 common gardens in the northern part of Belgium. The data were processed with cumulative logistic regression. The contribution of genetic and non-genetic components to the total variability varied between the four studied seasonal phenophases. The timing of flower opening displayed the smallest relative amount of intragenotypic variance (between ramets), suggesting a stronger genetic control and a lesser need at the individual plant level for plastic fine tuning to the micro-environment. In addition, whereas leaf bud burst showed the highest relative variance at the interpopulation level among all phenophases, probably at least partly attributable to local adaptation, flower opening displayed the highest intergenotypic variance, which may have been promoted more by assortative mating. Spring phenophases were strongly correlated (r = 0.89) as well as the autumnal phenophases (r = 0.72). Flower opening was not correlated with the autumnal phenophases. Timing of leaf bud burst and leaf senescence were negatively correlated, demonstrating that the length of the growing season enlarged or diminished among the studied genotypes. Although the two planting sites were only 24 km apart, all phenophases were advanced at the less exposed site, indicating a phenotypic plastic response. Together, our results suggest that in P. padus, flowering is less sensitive to environmental variation than leaf bud break and may show a lesser impact of a changing environment on this reproductive phenophase.

scholarly journals Functional analysis of Normalized Difference Vegetation Index curves reveals overwinter mule deer survival is driven by both spring and autumn phenology

2014 ◽  
Vol 369 (1643) ◽  
pp. 20130196 ◽  
Author(s):  
Mark A. Hurley ◽  
Mark Hebblewhite ◽  
Jean-Michel Gaillard ◽  
Stéphane Dray ◽  
Kyle A. Taylor ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Body Mass ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Mule Deer ◽  
Plant Phenology ◽  
Spring Phenology ◽  
Overwinter Survival ◽  
Wide Range ◽  
Functional Components

Large herbivore populations respond strongly to remotely sensed measures of primary productivity. Whereas most studies in seasonal environments have focused on the effects of spring plant phenology on juvenile survival, recent studies demonstrated that autumn nutrition also plays a crucial role. We tested for both direct and indirect (through body mass) effects of spring and autumn phenology on winter survival of 2315 mule deer fawns across a wide range of environmental conditions in Idaho, USA. We first performed a functional analysis that identified spring and autumn as the key periods for structuring the among-population and among-year variation of primary production (approximated from 1 km Advanced Very High Resolution Radiometer Normalized Difference Vegetation Index (NDVI)) along the growing season. A path analysis showed that early winter precipitation and direct and indirect effects of spring and autumn NDVI functional components accounted for 45% of observed variation in overwinter survival. The effect size of autumn phenology on body mass was about twice that of spring phenology, while direct effects of phenology on survival were similar between spring and autumn. We demonstrate that the effects of plant phenology vary across ecosystems, and that in semi-arid systems, autumn may be more important than spring for overwinter survival.

scholarly journals A survey of proximal methods for monitoring leaf phenology in temperate deciduous forests

2020 ◽  
Author(s):  
Kamel Soudani ◽  
Nicolas Delpierre ◽  
Daniel Berveiller ◽  
Gabriel Hmimina ◽  
Jean-Yves Pontailler ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Leaf Senescence ◽  
Vegetation Index ◽  
Broad Band ◽  
Flux Measurement ◽  
Spring Phenology ◽  
Area Index ◽  
Tree Phenology ◽  
Temperate Deciduous ◽  
Energy Exchanges

Abstract. Tree phenology is a major driver of forest-atmosphere mass and energy exchanges. Yet tree phenology has historically not been recorded at flux measurement sites. Here, we used seasonal time-series of ground-based NDVI (Normalized Difference Vegetation Index), RGB camera GCC (Greenness Chromatic Coordinate), broad-band NDVI, LAI (Leaf Area Index), fAPAR (fraction of Absorbed Photosynthetic Active Radiation), CC (Canopy Closure), fRvis (fraction of Reflected Radiation) and GPP (Gross Primary Productivity) to predict six phenological markers detecting the start, middle and end of budburst and of leaf senescence in a temperate deciduous forest. We compared them to observations of budburst and leaf senescence achieved by field phenologists over a 13-year period. GCC, NDVI and CC captured very well the interannual variability of spring phenology (R2 > 0.80) and provided the best estimates of the observed budburst dates, with a mean absolute deviation (MAD) less than 4 days. For the CC and GCC methods, mid-amplitude (50 %) threshold dates during spring phenological transition agreed well with the observed phenological dates. For the NDVI-based method, on average, the mean observed date coincides with the date when NDVI reaches 25 % of its amplitude of annual variation. For the other methods, MAD ranges from 6 to 17 days. GPP provides the most biased estimates. During the leaf senescence stage, NDVI- and CC-derived dates correlated significantly with observed dates (R2 = 0.63 and 0.80 for NDVI and CC, respectively), with MAD less than 7 days. Our results show that proximal sensing methods can be used to derive robust phenological metrics. They can be used to retrieve long-term phenological series at flux measurement sites and help interpret the interannual variability and trends of mass and energy exchanges.

scholarly journals Spring frost controls spring tree phenology along elevational gradients on the southeastern Tibetan Plateau

2017 ◽  
Author(s):  
Yafeng Wang ◽  
Bradley Case ◽  
Sergio Rossi ◽  
Liping Zhu ◽  
Eryuan Liang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Driving Forces ◽  
Climate Extremes ◽  
The Tibetan Plateau ◽  
Spring Phenology ◽  
Altitudinal Gradients ◽  
Leaf Unfolding ◽  
Spring Frost ◽  
Southeastern Tibetan Plateau ◽  
Spring Frosts

AbstractTemperature is considered to be a main driver of spring phenology, whereas the role of climate extremes (such as spring frosts) has long been neglected. A large elevational gradient of mature forests on the Tibetan Plateau provides a powerful space-for-time ‘natural experiment’ to explore driving forces of spring phenology. Combining 5-yr of in situ phenological observations of Smith fir (Abies georgei var. smithii) with concurrent air temperature data along two altitudinal gradients on the southeastern Tibetan Plateau, we tested the hypothesis that spring frost was a major factor regulating the timing of spring phenology. Onset of bud swelling and leaf unfolding in the study years occurred ≈ 18 or 17 days earlier, respectively, at the lowest (3800 m a.s.l.) elevation relative to upper treelines (4360 or 4380 m a.s.l.). The frequency of freezing events and last freezing date were critical factors in determining the timing of bud swelling along two altitudinal gradients, whereas onset of leaf unfolding was primarily controlled by the onset of bud swelling. This finding provides evidence for detrimental impacts of spring frost on spring phenology, which have been underappreciated in research on phenological sensitivity to climate but should be included in phenology models. It contributes to explain the declining global warming effects on spring phenophases, because climatic extreme events (e.g. spring frosts) tend to increase with warming.

scholarly journals A survey of proximal methods for monitoring leaf phenology in temperate deciduous forests

2020 ◽  
Author(s):  
Kamel Soudani ◽  
Nicolas Delpierre ◽  
Daniel Berveiller ◽  
Gabriel Hmimina ◽  
Jean-Yves Pontailler ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Leaf Senescence ◽  
Flux Measurement ◽  
List Type ◽  
Spring Phenology ◽  
Area Index ◽  
Tree Phenology ◽  
Temperate Deciduous ◽  
Energy Exchanges ◽  
Best Estimates

AbstractTree phenology is a major driver of forest-atmosphere mass and energy exchanges. Yet tree phenology has historically not been recorded at flux measurement sites. Here, we used seasonal time-series of ground-based NDVI (Normalized Difference Vegetation Index), RGB camera GCC (Greenness Chromatic Coordinate), broad-band NDVI, LAI (Leaf Area Index), fAPAR (fraction of Absorbed Photosynthetic Active Radiation), CC (Canopy Closure), fRvis (fraction of Reflected Radiation) and GPP (Gross Primary Productivity) to predict six phenological markers detecting the start, middle and end of budburst and of leaf senescence in a temperate deciduous forest. We compared them to observations of budburst and leaf senescence achieved by field phenologists over a 13-year period. GCC, NDVI and CC captured very well the interannual variability of spring phenology (R2 > 0.80) and provided the best estimates of the observed budburst dates, with a mean absolute deviation (MAD) less than 4 days. For the CC and GCC methods, mid-amplitude (50%) threshold dates during spring phenological transition agreed well with the observed phenological dates. For the NDVI-based method, on average, the mean observed date coincides with the date when NDVI reaches 25% of its amplitude of annual variation. For the other methods, MAD ranges from 6 to 17 days. GPP provides the most biased estimates. During the leaf senescence stage, NDVI- and CC-derived dates correlated significantly with observed dates (R2 =0.63 and 0.80 for NDVI and CC, respectively), with MAD less than 7 days. Our results show that proximal sensing methods can be used to derive robust phenological indexes. They can be used to retrieve long-term phenological series at flux measurement sites and help interpret the interannual variability and decadal trends of mass and energy exchanges.HighlightsWe used 8 indirect methods to predict the timing of phenological events.GCC, NDVI and CC captured very well the interannual variation of spring phenology.GCC, NDVI and CC provided the best estimates of observed budburst dates.NDVI and CC derived-dates correlated with observed leaf senescence dates.

scholarly journals Overestimation of the effect of climatic warming on spring phenology due to misrepresentation of chilling

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Huanjiong Wang ◽  
Chaoyang Wu ◽  
Philippe Ciais ◽  
Josep Peñuelas ◽  
Junhu Dai ◽  
...  
Keyword(s):  
Climate Change ◽  
Freezing Temperature ◽  
Future Climate Change ◽  
Dormancy Release ◽  
Climatic Warming ◽  
Ecosystem Models ◽  
Spring Phenology ◽  
Leaf Unfolding ◽  
Correct Understanding ◽  
Heat Requirement

Abstract Spring warming substantially advances leaf unfolding and flowering time for perennials. Winter warming, however, decreases chilling accumulation (CA), which increases the heat requirement (HR) and acts to delay spring phenology. Whether or not this negative CA-HR relationship is correctly interpreted in ecosystem models remains unknown. Using leaf unfolding and flowering data for 30 perennials in Europe, here we show that more than half (7 of 12) of current chilling models are invalid since they show a positive CA-HR relationship. The possible reason is that they overlook the effect of freezing temperature on dormancy release. Overestimation of the advance in spring phenology by the end of this century by these invalid chilling models could be as large as 7.6 and 20.0 days under RCPs 4.5 and 8.5, respectively. Our results highlight the need for a better representation of chilling for the correct understanding of spring phenological responses to future climate change.

scholarly journals Spatial variance of spring phenology in temperate deciduous forests is constrained by background climatic conditions

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Marc Peaucelle ◽  
Ivan A. Janssens ◽  
Benjamin D. Stocker ◽  
Adrià Descals Ferrando ◽  
Yongshuo H. Fu ◽  
...  
Keyword(s):  
Light Availability ◽  
Temperature Response ◽  
Climatic Conditions ◽  
Deciduous Tree ◽  
Spring Temperature ◽  
Spatial Variance ◽  
Spring Phenology ◽  
Leaf Unfolding ◽  
Temperate Deciduous ◽  
Heat Requirement

AbstractLeaf unfolding in temperate forests is driven by spring temperature, but little is known about the spatial variance of that temperature dependency. Here we use in situ leaf unfolding observations for eight deciduous tree species to show that the two factors that control chilling (number of cold days) and heat requirement (growing degree days at leaf unfolding, GDDreq) only explain 30% of the spatial variance of leaf unfolding. Radiation and aridity differences among sites together explain 10% of the spatial variance of leaf unfolding date, and 40% of the variation in GDDreq. Radiation intensity is positively correlated with GDDreq and aridity is negatively correlated with GDDreq spatial variance. These results suggest that leaf unfolding of temperate deciduous trees is adapted to local mean climate, including water and light availability, through altered sensitivity to spring temperature. Such adaptation of heat requirement to background climate would imply that models using constant temperature response are inherently inaccurate at local scale.

scholarly journals Inter-tree variability of autumn leaf phenology of European beech (Fagus sylvatica) on a site in Ljubljana, Slovenia

Les/Wood ◽  
2020 ◽  
Vol 69 (2) ◽  
pp. 5-20
Author(s):  
Nina Škrk ◽  
Angela Balzano ◽  
Zalika Črepinšek ◽  
Katarina Čufar
Keyword(s):  
Fagus Sylvatica ◽  
Monitoring Program ◽  
European Beech ◽  
Weather Conditions ◽  
Health Condition ◽  
Individual Variability ◽  
Spring Phenology ◽  
Leaf Unfolding ◽  
Environment Agency ◽  
Leaf Colouring

Temporal variability of leaf senescence (autumn phenology) was observed in 2020 in 11 European beech (Fagus sylvatica) trees in Tivoli, Rožnik and Šišenski hrib Landscape Park in Ljubljana, Slovenia, and also observed for spring phenology in the same year. General leaf colouring, BBCH94, occurred between 19 and 24 October 2020, with lower inter-individual variability than that of leaf unfolding, BBCH11. The trees had active leaves (time between leaf unfolding and leaf colouring) between 177 and 199 days. In only three trees total leaf fall, BBCH97, occurred before 19 November 2020. Leaf colouring of the tree included in the long-term monitoring program of the Slovenian Environment Agency ARSO occurred on 24 October 2020. This is 7 days later than the 65-year average of the same tree/location and is ascribed to weather conditions. Investigation of tree tissues showed that the width of the last formed tree-ring in the wood varied between 0.39 and 9.61 mm and in the phloem between 0.09 and 0.26 mm, and that the tissues reflect the health condition of the trees.

scholarly journals Integration of Transcriptomic And Proteomic Analyses Reveals Several Levels of Metabolic Regulation In The Excess Starch And Early Senescent Leaf Mutant lses1 In Rice

2021 ◽  
Author(s):  
Zhiming Chen ◽  
Yongsheng Wang ◽  
Rongyu Huang ◽  
Zesen Zhang ◽  
Jinpeng Huang ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Metabolic Regulation ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Starch Biosynthesis ◽  
Regulation Mechanism ◽  
Aba Signaling ◽  
Significant Differential Expression ◽  
Premature Leaf Senescence ◽  
Proteomic Analyses

Abstract Background: The normal metabolism of transitory starch in leaves plays an important role in ensuring photosynthesis, delaying senescence and maintaining high yield in crops. OsCKI1 (casein kinase I1) plays crucial regulatory roles in multiple important physiological processes, including root development, hormonal signaling and low temperature-treatment adaptive growth in rice; however, its potential role in regulating temporary starch metabolism or premature leaf senescence remains unclear. To reveal the molecular regulatory mechanism of OsCKI1 in rice leaves, physiological, transcriptomic and proteomic analyses of leaves of the mutant lses1 (leaf starch excess and senescence 1), allelic to osckI1, and its wild-type variety (WT) were performed. Results: Phenotypic identification and physiological measurements showed that the lses1 mutant exhibited starch excess in the leaves and an obvious leaf tip withering phenotype as well as high ROS and MDA contents, low chlorophyll content and protective enzyme activities compared to WT. Transcriptomic and proteomic analyses showed that the correlations of most genes at the transcription and translation levels were limited. However, the changes of several important genes related to carbohydrate metabolism and apoptosis at the mRNA and protein levels were consistent. The protein-protein interaction (PPI) network might play accessory roles in promoting premature senescence of lses1 leaves. Comprehensive transcriptomic and proteomic analysis indicated that multiple key genes/proteins related to starch and sugar metabolism, apoptosis and ABA signaling exhibited significant differential expression. Abnormal increase in temporary starch was highly correlated with the expression of starch biosynthesis-related genes, which might be the main factor that causes premature leaf senescence and changes in multiple metabolic levels in leaves of lses1. In addition, significant up regulation of four proteins associated with ABA accumulation and signaling were detected in the lses1 mutant, suggesting that ABA may involve in multiple metabolic regulation via LSES1/OsCKI1 and the formation of mutant phenotype in lses1 leaves.Conclusion: The current study established the high correlation between the changes in physiological characteristics and mRNA and protein expression profiles in lses1 leaves, and emphasized the positive effect of excessive starch on accelerating premature leaf senescence. The expression patterns of genes/proteins related to starch biosynthesis and ABA signaling were analyzed via transcriptomes and proteomes, which provided a novel direction and research basis for the subsequent exploration of the regulation mechanism of temporary starch and apoptosis via LSES1/OsCKI1 in rice.

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