Using ground observed Melia azedarach budburst, first leaf unfolding, and first flowering dates and daily mean temperature data (1981 to 2014) at 37 stations in China's subtropical and tropical ...zones, we identified the positive and negative temperature effects on spring phenology from winter and spring, and their spatial and seasonal variations. Then, we grouped the spatial variations into temperature effect phases. Lastly, we examined relationships between mean temperature during the positive effect phase and effective accumulated temperature during the negative effect phase. Results show that Melia azedarach spring phenology is positively influenced (delayed) by preseason winter temperatures and negatively influenced (advanced) by preseason spring temperatures. The negative spring temperature effect on the three phenophases was detected at all stations, while the positive winter temperature effect was apparent only at 51%–78% of stations. The number of stations with the positive winter temperature effect is larger in colder areas and for earlier occurring phenophases, and smaller in warmer areas and for later occurring phenophases. In addition, either negative responses of spring phenology to spring temperature or positive responses of spring phenology to winter temperature are more sensitive at warmer locations than colder locations. Further analyses indicate that the lower the mean temperature during the positive winter temperature effect phase at a specific station, the less the effective accumulated temperature needed for budburst, first leaf unfolding, and first flowering during the negative spring temperature effect phase at the same station. This implies that effective accumulated temperature during the negative effect phase depends on temperature status during the positive effect phase. Our study highlights that the interannual variation of Melia azedarach spring phenology is triggered by the net interaction impacts of winter and spring temperatures.
Melia azedarach spring phenology (like flowering shown in the image) is influenced by both a positive impact of preseason winter temperatures and negative impact of preseason spring temperatures. Positive winter temperature effect appears more often in colder than warmer areas. Sensitivity of phenology to spring/winter temperature is stronger in warmer than colder areas. Higher winter temperature can increase spring accumulated temperature requirements.
O objetivo deste estudo foi realizar o monitoramento fenológico de G. palustris ao longo dos meses de julho/2019 a junho/2020, e correlacionar com as variáveis meteorológicas na Serra Catarinense. ...Foram avaliadas a intensidade e sincronia das fenofases vegetativas e reprodutivas de 24 indivíduos em três áreas, localizadas em dois municípios de Santa Catarina, Brasil. Em G. palustris foi identificada a brotação contínua. Foi observada a presença de folhas maduras durante todo período e a senescência foliar apresentou intensidades variadas. A floração iniciou em dezembro estendendo até abril. As maiores porcentagens de botões florais presentes nas plantas ocorreram de janeiro a março/20 e a antese ocorreu de janeiro a maio, com maiores porcentagens em janeiro e março. Quanto à frutificação, foi observado o início com a presença de frutos imaturos em janeiro se estendendo até junho, mas o período de janeiro a março foi identificado com as maiores porcentagens de frutos imaturos nas plantas. A ocorrência de frutos maduros foi verificada nos meses de fevereiro a junho, sendo em fevereiro e março registradas as maiores porcentagens. Foi identificada a ausência de frutos senescentes somente nos meses de dezembro/2019 e janeiro/2020, e as maiores porcentagens ocorreram nos períodos de outono e inverno, coincidindo com a presença de folhas senescentes. Houve correlação entre temperatura e fotoperíodo para folhas maduras, desfolhamento e botões florais. A sincronia dos eventos fenológicos foi alta para aspectos vegetativos e baixa ou assíncrona para aspectos reprodutivos. Os padrões fenológicos da fenofase reprodutiva foram sazonais, ocorrendo no verão e outono (novembro a junho). Já a fenofase vegetativa ocorreu o ano todo, sendo que os maiores índices de brotação antecederam o período reprodutivo. Os resultados obtidos forneceram informações importantes acerca da fenologia desta espécie nesta região de ocorrência.
Summary
Changes in phenology are an inevitable result of climate change, and will have wide‐reaching impacts on species, ecosystems, human society and even feedback onto climate. Accurate ...understanding of phenology is important to adapt to and mitigate such changes. However, analysis of phenology globally has been constrained by lack of data, dependence on geographically limited, non‐circular indicators and lack of power in statistical analyses.
To address these challenges, especially for the study of tropical phenology, we developed a flexible and robust analytical approach – using Fourier analysis with confidence intervals – to objectively and quantitatively describe long‐term observational phenology data even when data may be noisy. We then tested the power of this approach to detect regular cycles under different scenarios of data noise and length using both simulated and field data.
We use Fourier analysis to quantify flowering phenology from newly available data for 856 individual plants of 70 species observed monthly since 1986 at Lopé National Park, Gabon. After applying a confidence test, we find that 59% of the individuals have regular flowering cycles, and 88% species flower annually. We find time‐series length to be a significant predictor of the likelihood of confidently detecting a regular cycle from the data. Using simulated data we find that cycle regularity has a greater impact on detecting phenology than event detectability. Power analysis of the Lopé field data shows that at least 6 years of data are needed for confident detection of the least noisy species, but this varies and is often >20 years for the most noisy species.
There are now a number of large phenology datasets from the tropics, from which insights into current regional and global changes may be gained, if flexible and quantitative analytical approaches are used. However, consistent long‐term data collection is costly and requires much effort. We provide support for the importance of such research and give suggestions as to how to avoid erroneous interpretation of shorter length datasets and maximise returns from long‐term observational studies.
Abstract The objective of this study is to describe the reproductive and vegetative phenological patterns of individuals of Copernicia alba, popularly known as “carandá,” in two areas of the Pantanal ...of Mato Grosso and to test the relations between their phenophases and climatic seasonality. We obtained the phenological aspects of the carandá through a biweekly observation of 22 individuals from two areas of the Pantanal of Mato Grosso between August 2015 and August 2017. The carandá population presented a perennial behavior, flowering during the dry season and greater leaf intensity in the transition period to the rainy season. Budding, although continuous, was intense in the rainy season, and the leaf deciduous pattern had a direct interference from the absence of rainfalls in the dry period. The incidence of floral buds occurred in the dry period, and the flowering occurred between the dry and rainy periods. The fruiting period occurred in the rainy season, indicating a high synchronism of phenophases.
Cotton-sunflower cropping system is a unique oilseed-based rotation. The real problem is overlapping sunflower-maturity with cotton-sowing. Investigations aim to tackle cotton-late-sowing through ...sowing-time-adjustment and cultivar-selection at cropping-system-level. Cotton (May 10th to June 24th) and sunflower (December 20th to February 03rd) sowing-dates were maintained biweekly. Maturity-time based cultivars were selected (early, medium, late) and variations in ambient-temperature through sowing-dates from 33.2 to 33.9 °C, 32.2 to 33.6 °C and 29.2 to 32.6 °C, length of emergence-squaring, squaring-flowering and flowering-maturity differed by 3.1, 1.5 and 5.1 days, respectively. Likewise, sunflower-sowing-dates based ambient-temperature ranged 13.7–18.1 °C, 16.3–17.5 °C and 23.8–28.5 °C at emergence-budding, budding-anthesis and anthesis-maturity, resulted in a difference of 13.5, 4.8 and 1.0 days. Results revealed that cotton late-sowing (May 10th to June 24th) and sunflower (December 20th to January 19th) resulted in reduces seedcotton, lint and achene yield by 19.9, 8.2 and 8.8 kg ha
−1
day
−1
. Oil productivity was the highest in cotton vide June 24th and in sunflower 04th January. In this cropping system, cotton is highly sensitive to sowing-dates for yield losses (35%) and sunflower less sensitive (14.4%). Meanwhile, yield variations in cotton-cultivars (12.5%) and sunflower-hybrids (10.0%). It was realized that sunflower December 20th hold great importance to assure minimum cotton yield-losses than looking for hybrids.
Resumen: Se estudió el potencial reproductivo de una población de Stenocereus queretaroensis, localizada en San José de Cosalima, municipio Tabasco, Zacatecas. Los objetivos fueron: estudiar la ...variación temporal en la producción de flores, frutos y semillas durante 2 años en 3 parajes; determinar la viabilidad y germinación de la semilla; analizar el efecto de un tratamiento pregerminativo en la eficiencia y velocidad de la germinación, y cuantificar el porcentaje de emergencia y supervivencia de plántulas en campo. De febrero de 2014 a julio de 2015 se siguió la fenología reproductiva del pitayo. Se encontraron diferencias en la producción de flores, frutos y semillas entre parajes y años de evaluación. Se observaron diferencias estadísticas significativas en la viabilidad y germinación de las semillas, así como en la emergencia de plántulas entre parajes y microhábitats diferenciados por tipo de cobertura de dosel. Los resultados de este estudio mostraron que el potencial reproductivo de S. queretaroensis se incrementó en el año de mayor precipitación (2015), con el uso de un tratamiento pregerminativo y bajo el dosel vegetal de la propia especie. Estos resultados pueden ser aplicados en programas de aprovechamiento y conservación del pitayo in situ.
http://dx.doi.org/10.5902/1980509817464Brosimum gaudichaudii Trécul., espécie típica do cerrado, é muito apreciada pelo sabor adocicado dos seus frutos e como planta medicinal no tratamento do ...vitiligo. Os estudos fenológicos fornecem subsídios para a compreensão da dinâmica dos ecossistemas florestais e para o manejo de espécies nativas. Desse modo, o objetivo nesta pesquisa foi avaliar a fenologia Brosimum gaudichaudii Trécul. por meio de dois métodos: a intensidade do evento fenológico caracterizada pela escala de Fournier e a presença/ausência do evento, ambos expressos pelos índices de atividade e intensidade. O acompanhamento dos estádios fenológicos foi feito a cada 20 dias, de 2006 a 2008, em 49 indivíduos selecionados aleatoriamente. O índice de sincronia (Z) foi de 0,96 para enfolhamento; 0,65 para brotação; 0,69 para floração e de 0,72 para frutificação. A abscisão foliar ocorreu em julho e a brotação foi mais intensa (80%) em outubro. A floração ocorreu entre junho e outubro de 2007, com pico de intensidade em agosto (52%) e maior atividade em setembro (92%); a frutificação ocorreu entre agosto e dezembro de 2007, com 91% dos indivíduos em atividade em outubro, porém, intensidade de 25% para o mesmo período. Brosimum gaudichaudii Trécul. é planta decídua e os eventos fenológicos estão condicionados à sazonalidade das variações climáticas, principalmente precipitação.
Abstract Phenological processes are strongly affected by environmental conditions. In this study we investigate the phenological patterns of six tree/shrub species in three Caatinga fragments and ...analyze the influence of rainfall and air temperature on these processes. Circular statistics was used to analyze the vegetative and reproductive phenophases over 12 months (dry and rainy seasons) in the years 2016 to 2017 and 2018 to 2019. Spearman’s linear correlation test (r) was applied to verify the influence of meteorological variables of the two years of study on the phenological stages for each species. All species showed a seasonal pattern for vegetative phenophases. Reproductive phenophases were recorded in the two study periods only for one species. There was correlation of the phenophases only with rainfall, but not for all species. The amount of rainfall below the historical average indicates that precipitation is the most limiting factor for flowering in the evaluated species.
A field experiment was conducted to evaluate agrometeorological parameters associated with seed yield of Indian mustard (Brassica juncea L.) varieties in an organic production system. During the ...study, significant variation was recorded in crop phenophases, growth, yield attributes, and seed yield of mustard. Varieties NRCHB-101 and Pusa Mustard-25 have taken significantly minimum days to commence flowering (46–48 days) and attaining physiological maturity (89–90 days). Variety RGN-48 being at par with RH-406 and RGN-229, recorded significantly higher plant height, while RGN-229 recorded the significantly highest biomass accumulation at all the growth stages. Varieties RH-406, Pusa Bold, and DRMRIJ-31 recorded significantly higher seeds per siliqua (16.2–16.5), whereas significantly higher test weight was recorded in Pusa Bold (6.3 g) and DRMRIJ-31 (6.0 g). In seed yield, variety RH-406 (1.97 t/ha) and DRMRIJ-31 (1.42 t/ha) were found significantly highest and lowest, respectively. A significant positive correlations of mustard seed yield was noticed with biomass accumulation at 30 DAS (r=441**), 60 DAS (r=0.614**), 90 DAS (r=0.620**) and biological yield at harvest (r=0.496**). Contrary to test weight, seeds per siliqua had shown a positive effect (r=0.266*) on the seed yield of the mustard. Seed yield of mustard was also influenced by some agrometeorological indices with correlation coefficients (r) of mean minimum temperature at flowering and physiological maturity and mean maximum temperature at physiological maturity were -0.207*, -0.249*, and -0.241*, respectively. Net solar radiation and cumulative temperature difference at physiological maturity also had significant and positive effects on the seed yield of mustard.
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