O objetivo deste trabalho foi avaliar o efeito do ácido salicílico (AS) aplicado em pós-colheita de amora-preta, acerola, couve manteiga, espinafre e rosas sobre a conservação e a indução de resistência. O delineamento experimental foi inteiramente ao acaso, com quatro repetições e os tratamentos foram baseados nas concentrações das soluções com AS 0,0; 0,5; 1,0; 1,5; e 2,0 mM. As culturas foram imersas nas soluções com os diferentes tratamentos e após armazenadas a 8°C. Para as frutas (amora-preta e acerola) as avaliações realizadas foram perda de massa da matéria fresca, teores de sólidos solúveis totais (SST), acidez titulável (AT), ácido ascórbico e incidência de podridões. Nos intervalos de 24, 48, 96 e 192 horas após a aplicação dos tratamentos, retirou-se amostras de frutos para determinação de proteínas totais, antocianinas, flavonóides e atividade das enzimas fenilalanina amônia-liase (FAL), quitinases e β-1,3-glucanase. Tais análises foram realizadas para todos os tratamentos, com exceção de quitinase e β-1,3-glucanase, sendo estas avaliações feitas somente para frutos tratados com 2,0 mM e a testemunha. Para as hortaliças (couve manteiga e espinafre) as avaliações foram perda de massa da matéria fresca, podridões, teor de vitamina C e clorofilas. Em intervalos de 24, 48, 96 e 192 horas após a aplicação dos tratamentos, determinou-se o teor de proteínas, fenóis totais, atividade da FAL e peroxidases. Para as rosas foram realizadas análises visuais de curvatura do pedúnculo, turgescência e escurecimento de pétalas. Ao final do experimento, avaliaram-se a perda de massa da matéria fresca, e teor de clorofilas nas folhas. Com intervalos de 24 horas, retirou-se uma amostra das pétalas para determinação de proteínas totais e atividade da FAL e peroxidases. Para amoras-pretas houve aumento do teor de proteínas e ativação da β-1,3-glucanase com a aplicação de AS. Os teores de antocianinas e flavonóides e a atividade da FAL, tiveram alterações no decorrer do experimento em função da aplicação de AS. Os tratamentos não foram significativos para perda de massa da matéria fresca, AT, SST, incidência de podridões, ácido ascórbico e atividade de quitinase para essa fruta. Para acerolas, a AT foi maior e os SST foram menores naquelas tratadas com AS. Os tratamentos não foram significativos para perda de massa da matéria fresca e ácido ascórbico de acerola. Houve redução da incidência de podridões em frutos com aplicação de AS, ativação das enzimas quitinases, β-1,3-glucanase e FAL e, aumento nos teores de antocianinas e flavonoides para acerola. Para couve manteiga a aplicação de AS manteve os teores de proteínas e fenóis totais em níveis mais elevados, e interferiu na atividade das peroxidases. Não houve significância para perda de massa da matéria fresca, teor de vitamina C, clorofilas, podridões e atividade de FAL. Para espinafre as maiores concentrações de AS diminuíram a perda de massa da matéria fresca e mantiveram os teores de proteínas mais elevados. Os tratamentos não interferiram no teor de clorofilas, fenóis totais, e atividade da peroxidases e FAL. Houve efeito nos teores de proteína totais, atividade da FAL e peroxidase nas hastes das rosas com a aplicação de solução contendo AS. As rosas tratadas com a maior concentração de AS mantiveram-se com as notas mais elevadas para curvatura de haste, turgescência e escurecimento de pétalas, ou seja, com melhor aspecto visual. / The aim of this work was to evaluate the salicylic acid (SA) effect applied in the blackberry, acerola, kale, spinach and roses postharvest for the conservation and resistance induction. The experimental design was completely randomized, with four replications and the treatments were based on the solutions concentrations with SA 0.0, 0.5, 1.0, 1.5 and 2.0 mM. The vegetable organs from the cultures were immersed in the solutions with different treatments and after it was stored at 8 °C. For the fruit (blackberry and acerola) the fresh matter weight losses, total soluble solids (TSS), titratable acidity (TA), ascorbic acid and rot incidence were evaluated. During the intervals of 24, 48, 96 and 192 hours after treatment application, fruit samples were separated for total protein, anthocyanins, flavonoids and phenylalanine ammonia lyase (PAL), chitinase and β-1,3-glucanase enzymes activities were determinate. These analyzes were applied for all treatments, with the exception of chitinase and β-1,3-glucanase, which were evaluated only for fruits treated with 2.0 mM concentration and control treatment. For the vegetables (kale and spinach) the fresh mass losses, rot incidence, vitamin C and chlorophyll were evaluated. During the intervals of 24, 48, 96 and 192 hours after treatment application, the total protein, total phenols, phenylalanine ammonia lyase (PAL) and peroxidase enzimes were evaluated. For roses the peduncle curvature, turgescence and petals darkening were visual evaluated. When the experiment time finished, the fresh weight losses and the leaf chlorophyll content were evaluated. During 24 hour intervals, collected a petals sample to determine the total protein and PAL and peroxidase activities. For blackberries there was an increase of protein level and the β-1,3-glucanase activation with the application of SA. The anthocyanins and flavonoids contents and the PAL activity, had changes during the experiment due to the SA application. The treatments were not significant for fresh mass losses, TA, TSS, rot incidence, ascorbic acid and chitinase activities for this fruit. In the acerola, the TA was higher and TSS were lower in the fruit treated with SA. The treatments were not significant for fresh mass losses, of ascorbic acid content. There was a reduction in the fruit rots incidence with application of SA and an activation of chitinase, β-1,3-glucanase and PAL activity enzymes, and it increased anthocyanins and flavonoids contents for acerola. The SA application in the kale kept the protein and total phenol with higher levels and it interfere in the peroxidases activity. There was no significant treatment effect for fresh weight losses, vitamin C, chlorophyll, rot incidence and PAL activity. The highest SA concentrations decreased the fresh weight losses and they kept the higher proteins contents for spinach. The treatments did not affect the chlorophyll content, total phenolics and peroxidase and PAL activities.There wasn't treatment effect about total protein content, PAL and peroxidase activity in the roses stems. The rose treated with the highest SA concentration presented higher grade evaluation for peduncle curvature, turgescence and petals darkening, ie, the best visual aspect.

No description available.

In agreement with global patterns of climate change and increasing temperatures in the tropical oceans, the Northern Red Sea (NRS) has been warming over the last few decades. Using 18 years of remotely-sensed chlorophyll-a data (Chl-a, an index of phytoplankton biomass), we investigate the potential impacts of climate warming on phytoplankton abundance and phenology in the Northern Red Sea by exploring the mechanistic links with the regional physical environment. The results of the analysis reveal that, in accordance with other tropical ecosystems, phytoplankton biomass in the NRS will decrease in response to warmer climate scenarios. This is attributed to lower heat fluxes (heat loss to the atmosphere) during the bloom period, and enhanced vertical stratification, which prevents vertical mixing of nutrients into the euphotic layer. In addition, we show that during warmer conditions (when heat fluxes are weakened), the winter bloom initiates significantly later (by up to 10 weeks) and its duration is considerably reduced. The biological implications of alterations to phytoplankton phenology may include increased larval mortality of pelagic species, reduced recruitment, fisheries impacts and changes to community structure.

The cryosphere has been shown to be particularly adept as a proxy for climate change by various studies. Accordingly, historical records from the field of ice phenology have been harvested by climate scientists for the express purpose of studying the temporal variation of ice phenomena, namely freeze-up and ice-out. Ice-out records from 20 lakes in Maine, U.S.A. were collected and clustered by z-score for this thesis. Rather than attempt to relate ice-out to spring air temperature or global teleconnections/oscillations, the Spatial Synoptic Classification (SSC) method was used to encapsulate several meteorological variables that could have a bearing on ice-out variation. The balance between occurrence of relatively cool Moist Polar (MP) and relatively warm Dry Moderate (DM) weather-types during the winter-spring "superseason" was found to be a synoptic barometer of whether ice-out would occur seasonably early or late. The significance of this is predicated upon the finding that quantity of DM days has steadily risen at the expense of MP days during the latter-half of the twentieth-century, in accordance with observed climatic warming during the same period. The remaining SSC weather-types, most notably omnipresent Dry Polar (DP), remained generally stable during the historical record in Maine, further undergirding the significance of the DM-MP relationship. / Master of Science

Niche differentiation is the most recognized species coexistence mechanism, of which, the temporal differentiation of species, i.e. phenological differentiation has gained an increasing interest of ecologists. However, as an important dimension of phenology, the phenology of growth has drawn relatively few attentions due to the lack of sufficient phenological data. Therefore, the aim of this thesis is to examine potential role of temporal differentiation of plant growth patterns in plant coexistence. I first collected data on growth phenology of 381 perennial herbs in the Botanical Garden of Charles University in Prague within one growing season (in 2015). Using this database, I addressed the general patterns of growth phenology among perennial herbs. I distinguished two contrasting growth patterns: (1) species with early peak growth had high standardized growth rates in contrast to late species, reflecting the survival under forest canopy, where species are selected to grow early and fast before the development of tree canopy which restricts their size; (2) tall species showed later peak growth than short species, associating with (asymmetric) competition for light in open habitats, where the main selection factor is for tall stature, which cannot be attained early in the season. Then, by linking...

Chauliognathus pensylvanicus (De Geer) and C. marginatus (Fabr.) are two of the most common species of cantharid beetles observed in agroecosystems in Virginia. Despite their widespread abundance and early recognition and description in the 1700s, little is known about their phenology and ecological role in agricultural systems. Immatures have been recorded feeding upon soft-bodied insects such as lepidopteran larvae, and adults frequently visit flowering plants, where they eat nectar and/or pollen. Beyond those observations, relatively little is known about these species, which are conspicuous elements on and around farms, though there is considerable potential for their use as pollinators and predators in a biological pest control context. I employed a phenological study to determine the period of C. marginatus activity in Southwestern Virginia, and found adults active on a variety of flowers from mid-May to late July. On these flowers, they spent a large percentage of their day mating or feeding, with significant differences in the percentage of beetles participating in behaviors based on time of day and beetle sex, but not based on month. The majority of C. marginatus observations occurred on narrowleaf mountain mint (Pycnanthemum tenuifolium Schrad.), poison hemlock (Conium maculatum L.), and wild bergamot (Monarda fistulosa L.). I also used a community science-based approach to evaluate the usage of host plants and flower colors by C. marginatus and C. pensylvanicus. Chauliognathus marginatus utilized white flowers more than expected based on their potential availability, while C. pensylvanicus utilized yellow flowers over all other flower colors and more than expected based on their potential availability. Communities of flowers available to and observed with C. marginatus and C. pensylvanicus differed significantly at the family and genus levels. Laboratory bioassays supported these conclusions regarding C. pensylvanicus color preference, but not C. marginatus color preference. Lastly, because of their susceptibility to nontarget chemical exposure in agroecosystems, I tested the efficacy of both organic and conventional vegetable insecticides against C. marginatus adults. The highest mortality was seen in the acetamiprid, flupyridifurone, sulfoxaflor, and imidacloprid treatments, which reached 97-100% mortality at two days after treatment. High mortality (60-97% two days after treatment) was also seen in the organic treatments containing azadirachtins, pyrethrins, and Chromobacterium subtsugae strain PRAA4-1T. Mortality in the Burkholderia spp. strain A396 and spinosad treatments was not significantly different from that of the controls, however, control mortality was relatively high in both assays. / Doctor of Philosophy / Soldier beetles are common but underappreciated members of many ecosystems across the world. Two species are seen especially frequently on or around farms in Virginia: the margined leatherwing and the goldenrod soldier beetle. These beetles are active during different periods of the year (spring and fall, respectively), and adults gather in large numbers on flowering plants and may be beneficial pollinators of some flower species. Their immatures are stealthy and typically crawl along the ground, but may climb into crop plants to eat pest insects. Because of these potential roles in pest management, we studied their yearly activity, preferences in flower types and colors, and their susceptibility to chemical insecticides that are commonly used in vegetable crops. Margined leatherwing adults were active on wildflowers and flowering weeds from mid-May to late July. While they were on these flowers, they spent most of their day mating and feeding. Most of the observations we made were on narrowleaf mountain mint (a native perennial wildflower), poison hemlock (a toxic biennial invasive weed), and wild bergamot (a native perennial wildflower). I was interested in determining what flowers and flower colors each soldier beetle was found most frequently on throughout their entire range, so we used community science data collected from iNaturalist to evaluate those questions. Margined leatherwings were found much more often on white flowers than flowers of any color, and more than I expected based on the proportion of white flowers blooming in the spring. Goldenrod soldier beetles were found much more often on yellow flowers, and more than I expected based on the proportion of yellow flowers that bloom in the fall. The types of flowers blooming for each of these two species were different, as well as the types of flowers they visited. Our results were partially supported with a laboratory experiment where beetles had to choose colored panels to escape an enclosure; the goldenrod soldier beetles chose the yellow panel a great majority of the time, but the margined leatherwings did not choose the white panel as much as we expected. These differences in color and flower preferences are interesting and should be explored further. Finally, I tested several organic and conventional (non-organic) insecticides against margined leatherwing adult beetles to see how they would react if incidentally exposed in a farm setting. Insecticides of both types caused considerable mortality over two days, though two of the products we tested seemed not to have major negative effects on the beetles. This experiment was difficult because it seems that margined leatherwings are sensitive to being contained to experimental chambers, and many died without being exposed to any insecticide at all. In summary, these beetles are important, unique, and interesting, and deserve more study, especially regarding their potential role in agricultural pest management. These studies are some of the first to explore the behavior, host plants, and insecticide tolerance of these common soldier beetles, but will hopefully inspire others to look deeper into their biology in the future.

Trees, like many other organisms, decrease their rate of metabolic activities to cope up with harsh environments. This stage of "dormancy" is marked by shedding of leaves and bud-set in deciduous trees. Recent studies have revealed the role of the circadian clock in synchronizing the timing of dormancy and physiology for conferring fitness in trees. To better understand the possible role of natural selection on circadian clock-related genes in climatic adaptation, I took a candidate gene approach, selecting circadian clock genes, some of which had been functionally validated, and others hypothesized, to identify signatures of natural selection in Populus trichocarpa and P. deltoides. Using both frequency spectrum based tests and tests of heterogeneity, I identified genetic variants deviating from selective neutrality. Results reveal that photoreceptors and dormancy regulator genes may have been the targets of natural selection. Nearly the same levels of selective constraints were found in different functional groups of genes irrespective of pleiotropy. Further, upstream regions of all genes showed high selective constraint, with some of them (FT-2, PIF-4, FRIGIDA) showing significantly higher variation than the other genes, hinting at the role of non-coding regulatory regions in local adaption. In some cases, the same genes in both species appeared as outliers, including PIF-6, FRI, FT-2, SRR1, TIC, and CO, which might reflect their common role in adaptation across species boundaries. All of these results indicate a complex nature of phenology regulation and local adaptation in Populus species with photoreceptors and dormancy regulator genes playing key roles. / Master of Science

No description available.

This study computed the Normalized Difference Vegetation Index (NDVI) products derived from NOAA AVHRR, MODIS, and SPOT VGT sensors. NDVI products from different instruments vary in spatial resolution, temporal coverage and spectral range. As a result, multi-sensor NDVI products are rarely used in a single phenological study. In order to evaluate the difference and similarity of NDVI records from the three sensors, I used EPA Eco-region frameworks to determine the average annual Start of Season (SOS) and End of Season (EOS) of Contiguous United States, and analyzed dates among datasets. In addition, I created 1127 sample points within the study area, and compared relationship between SOS/EOS based on land cover. The objectives of this thesis are to: 1) compare multi-sensor NDVI data using phenological models, 2) define a strategy to merge multi-sensor NDVI products to a single phenological product without direct NDVI conversion. The spatial and statistical analysis revealed that the Land Surface Phenology (LSP) measurements retrieved from NDVI time series from different sensors follow linear and positive relationships where compared by either eco-region or sample point. The historical record of AVHRR combined with the modern MODIS and SPOT data provides a critical and reliable perspective on phenological patterns in Contiguous United States area. The success of this study will help LSP by providing understanding of how different instruments can be combined to generate multi-sensor NDVI data for phenology. / Master of Science

‘Wonderful’ pomegranate flowering and fruiting habits are not well understood. Characterizing any relationship between flowering habit and fruit size and quality could lead to effective cultural practices for producing high-value fruit. Five mature ‘Wonderful’ pomegranate trees were monitored every 5-14 days throughout the 2015 growing season. Newly emerged flowers were tagged and characterized with respect to sex (determined by ovary shape and style length at anthesis), clustering habit, age of wood on which floral buds were borne, and direction of wood growth. More than 1,100 hermaphroditic flowers were identified and ovary/fruit diameter was recorded throughout the season. In addition to tagging 1,800 staminate flowers at anthesis, approximately 14,000 abscised staminate flowers were collected and used to estimate total flower number and the ratio of hermaphroditic (fruit producing) to staminate flowers. Trees were strip picked at harvest. Fruit weight, maximum hemispheric diameter and exocarp color were recorded. Arils (seeds with a fleshy seed coat) were removed and weighed; aril number was estimated from the weight of 100 arils, and aril titratable acidity and total soluble solids were measured. The age of wood on which flowers were borne was a significant predictor of flower sexual condition. One-year-old wood produced the highest number of flowers (70% of total) with the smallest proportion of hermaphroditic flowers (5%) for any age of wood. Two-year-old wood produced fewer flowers (19% of total) with 10% hermaphroditic flowers. Wood that was greater than two years old produced 10% of total flowers and 20% were hermaphroditic. Overall, 93% of the flowers were staminate. Despite the low proportion of hermaphroditic flowers produced on one-year-old wood, 57% of marketable sized fruit were produced on one-year-old wood. There were three distinct bloom periods, the first lasting approximately 6 weeks. Bloom time was highly predictive of fruit quality. Late-blooming flowers produced low-quality fruit that were smaller in diameter with fewer arils and poor exocarp color. Such fruit accounted for approximately 13% of total fruit weight. Location within the canopy influenced fruit diameter significantly. Flowering rarely occurred in the typically “closed” interior of the canopy and flowers in the northwest tree quadrant were less likely to be early blooming or hermaphroditic than flowers in other quadrants. The results suggest that development of cultural methods that limit excessive production of staminate flowers reduce late-season flowering and/or fruit production and/or increase light exposure to fruiting wood could increase the production of high-value fruit for ‘Wonderful’ pomegranate.