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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu15947427740661272021-08-03T07:15:41Z Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon Ertle, John Michael Horticulture Agriculture Plant Biology Plant Sciences Physiology watermelon grafting chilling physiology abiotic stress chilling degree hours low-temperature grafted nongrafted fruiting vegetable crop cucurbitaceae citrullus lanatus transportation shipping flowering development seedling In recent years, the North American region has seen increased usage of grafted vegetable transplants to reduce soil-borne disease incidence, increase tolerance to abiotic stress, enhance fruit quality, and increase yields over conventional nongrafted transplants. Grafting itself is a unique agrotechnology that merges a vegetable crop (scion) with the root system of another plant (rootstock) to form one transplant that benefits from both traits. In North America, a recent survey showed nearly 60 million grafted transplants are produced annually for fruiting vegetable crops, including tomato, watermelon, cucumber, pepper, eggplant, and muskmelon. Due to the limited number of nurseries in North America, transplants are commonly shipped 3-5 d to distant producers and have reportedly experienced chilling stress during transportation that reduces transplant quality and may affect post-transplanting performance. However, few studies have explored the specific effects of transport-related chilling stress on seedling quality and post-transplanting development. Using watermelon (Citrullus lanatus), a highly chilling sensitive member of the Cucurbitacea family, we examined effects of acute chilling stress on seedlings quality and post-transplanting development. When grafted and nongrafted seedlings were exposed to 0 - 48 h of 3 °C chilling, we found that seedling quality and post-transplanting development were unaffected by chilling. However, when the chilling temperature was reduced to 1 °C, seedlings exhibited increased visual damage of seedlings with longer durations, decreased chlorophyll fluorescence (Fv/Fm), and increased delays in the number of days it took for plants to reach male and female flower anthesis after transplanting. Nongrafted plants had longer delays in days to flower anthesis than grafted plants, indicating that grafted plants may have been more resistant to chilling or had enhanced flower primordia development that reduced the effects of acute chilling. Based on these findings, we chilled nongrafted watermelon for various durations at chilling temperatures between -0.4 and 1.2 °C to determine if the chilling stress could be a cumulative response below a specific threshold temperature. Threshold temperatures, or base temperatures (BT), between 3 and 15 °C were found so that various measures of seedling quality were highly correlated with chilling degree hours (CDH). We found that seedling damage and reductions to Fv/Fm were highly correlated with CDH accumulation at base temperatures of 15 and 3 °C, respectively. Further, delays in female flower development increased linearly with CDH when a BT was selected as 4 °C. Therefore, reproductive development was directly inhibited by the chilling temperatures, and 4 °C was a critical temperature that caused post-transplanting reproductive delay. This result was confirmed when using the CDH model to analyze our previous results, indicating that this model can be used to predict delays in plant reproductive development when given various chilling conditions. Our results suggest that long-distance transportation of transplants above 4 °C will allow proper post-transplanting development without delays. 2020 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1594742774066127 http://rave.ohiolink.edu/etdc/view?acc_num=osu1594742774066127 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Horticulture
Agriculture
Plant Biology
Plant Sciences
Physiology
watermelon
grafting
chilling
physiology
abiotic stress
chilling degree hours
low-temperature
grafted
nongrafted
fruiting vegetable crop
cucurbitaceae
citrullus lanatus
transportation
shipping
flowering
development
seedling
spellingShingle Horticulture
Agriculture
Plant Biology
Plant Sciences
Physiology
watermelon
grafting
chilling
physiology
abiotic stress
chilling degree hours
low-temperature
grafted
nongrafted
fruiting vegetable crop
cucurbitaceae
citrullus lanatus
transportation
shipping
flowering
development
seedling
Ertle, John Michael
Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon
author Ertle, John Michael
author_facet Ertle, John Michael
author_sort Ertle, John Michael
title Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon
title_short Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon
title_full Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon
title_fullStr Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon
title_full_unstemmed Effects of Short-term Chilling Stress on Seedling Quality and Post-transplanting Growth of Grafted and Nongrafted Watermelon
title_sort effects of short-term chilling stress on seedling quality and post-transplanting growth of grafted and nongrafted watermelon
publisher The Ohio State University / OhioLINK
publishDate 2020
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1594742774066127
work_keys_str_mv AT ertlejohnmichael effectsofshorttermchillingstressonseedlingqualityandposttransplantinggrowthofgraftedandnongraftedwatermelon
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