Browsing by Subject "false spring"

Now showing 1 - 4 of 4
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    Damage measurements and reproductive outcomes following phenologic delay and floral freezing of a population of Prunus pumila plants
    (2024-06-06) Lake Diver, Danielle A; Savage, Jessica A; jsavage@d.umn.edu; Savage, Jessica; Savage research team
    There are advantages flowering early in the spring, which include greater pollinator fidelity and longer fruit maturation time. But plant phenology has advanced in recent years making many plants vulnerable to freezing damage from late frosts. To determine the costs and benefits of flowering early in the spring, we exposed Prunus pumila plants to two freezing treatments and a delayed flowering treatment in subsequent years. Data were collected on ovary swelling, fruit production and pollinator visitation on hand-and open-pollinated plants in all treatments. We also measured tissue damage after freeze events. Our results suggest that flowering time and temperature affect reproductive success, with fewer fruits produced after hard freezes. The same was not true for light freezes, which had minimal impact on reproduction. Freezing damage to plants after a hard freeze did affect the number of Dipteran pollinators but not the overall pollinator visitation rate. Despite the clear impact of freezing temperatures on plant reproduction, there were also advantages for flowering early as reproductive output decreased during with delayed flowering. Our findings suggest that Prunus pumila will retain the ability to attract pollinators and produce viable seeds if exposed to false spring conditions that involve a light freeze, but hard freezes may reduce yield by an order of magnitude. Although the advantages to flowering early may outweigh the risk of freezing damage under current conditions, it is possible that flower viability may be constrained under continued climate warming.
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    Data on tissue injury and conductivity of flowers at different temperatures along with method validation
    (2023-11-16) Savage, Jessica A.; Olson, Mady; Hudzinski, Sydney; jsavage@d.umn.edu; Savage, Jessica A.; Savage research team
    These data are for a paper on how to use the electrolyte leakage method to measure floral freezing tolerance. The files include tests of different sample preparation methods and temperate response curves for a handful of species.
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    Floral freezing tolerance of Minnesotan woody and semi-woody plants
    (2024-02-29) Savage, Jessica A.; Vandenheuvel, Britton; Fakhreddine, Qadry; jsavage@d.umn.edu; Savage, Jessica A.; Savage research team
    Data collected for a study on floral freezing tolerance of native trees and shrubs. The goal of the project was to determine if native flowers are vulnerable to freezing temperatures and how their vulnerability to freezing temperatures relates to their flowering time.
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    Weighing the Risks and Benefits of Flowering Early for the Woody Perennial Prunus pumila (Rosaceae)
    (2022-05) Lake Diver, Danielle
    As global weather patterns become increasingly unpredictable, the need to study the impact of this phenomenon on natural and anthropocentric ecosystems alike is increasingly urgent. Based on climate change predictions for the rest of this century, much previous research has been conducted to reveal plants’ response to stress from heat and drought. However, fewer studies have focused on the response of perennial plants to false spring, or freezing after de-acclimation, another possible result of climate change. Plant phenology has already begun to advance by weeks since the middle of the twentieth century, which makes plants that flower and leaf out early particularly vulnerable to freezing damage from late spring frosts. Temperature during anthesis (when open flowers are present on a plant) has a significant impact on fertility, floral metabolism, and the production and quality of floral rewards that attract pollinators. Therefore, there may be advantages to flowering early that outstrip the potential risks, especially if pollinators also adjust their phenology to warming conditions. To determine whether earlier flowering plants were at risk for freezing damage, we first monitored a population of Prunus pumila with artificially delayed phenology over the course of the 2020 growing season. We measured flower and fruit number and mass, pollinator visitations, the effects of floral age on hand pollination, and seed germination. Consistent with previous studies, our results suggest that flowering time and temperature at anthesis affect reproductive success, with fewer fruits produced in warmer conditions. To build on this work, in 2021, we examined the effects of floral freezing on P. pumila pollinator attraction and reproductive success. Field-grown potted plants were exposed to one of two sub zero (°C) temperatures or a near-freezing control temperature. Flower samples were assessed for tissue damage through electrolyte leakage and stereo microscopy. In addition, a subset of flowers was hand pollinated or bagged to exclude insects and to gauge the effects of pollen limitation and selfing, respectively. Plants were then returned to the field and observed over the course of flowering for pollinator visitation and monitored for signs of successful fertilization and reproduction. This study showed that, in general, P. pumila buds and flowers are resistant to light freezing but not to hard freezing, but this difference did not affect overall pollinator visitation rate. Our findings will contribute to the current knowledge of Prunus, a global genus with high economic and ecologic value that could be greatly impacted by climate change.