Temporary Suppression of Radicle Elongation of Germinated Impatiens Seeds by Low Oxygen Concentrations

Polking, Gary F.; Gladon, Richard J.; Koranski, David S.

doi:10.21273/hortsci.29.9.1031

Cited by 4 publications

(8 citation statements)

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“…Seeds were sown at one time, and 0.5 to 1.0 mL of deionized water was added 12 h after sowing. For the modified-atmosphere treatment, 25 germinated seeds were placed in a 5 • 5 array on two layers of a deionized, water-saturated (8 mL) germination blotter in a 9.0 • 6.7 • 1.2-mm clear plastic box without a lid (Polking et al, 1994).…”

Section: Methodsmentioning

confidence: 99%

“…The clear plastic boxes with 25 germinated seeds were placed in a wide-mouth, 1-L Mason jar laid horizontally in a growth chamber. Jars were sealed with dome lids modified to contain a gas inlet, a gas outlet, and a sampling port (Polking et al, 1994). Modified atmospheres were obtained with a two-stage, capillary tube mixing system with two air exchanges per hour (Diesburg et al, 1989;Polking et al, 1994).…”

Section: Methodsmentioning

confidence: 99%

“…Techniques such as density separation and fluid drilling allow removal of nonviable presown germinated seeds, and this permits quicker and more uniform germination (Pill, 1990;Taylor and Kenny, 1985;Taylor et al, 1981). Polking et al (1994) researched the technique of presowing germination, but germinated seeds could be held for only 12 to 24 h at 1% to 2% O 2 without loss of seedling quality, and a longer holding time may be desirable. When seed priming or presowing treatments were successful, deterioration and improper seed storage lead to losses of longevity and seed efficacy (Bruggink et al, 1999;Taylor et al, 1998).…”

mentioning

confidence: 99%

“…Low-O 2 environments in the root zone reduce plant growth and development. In some scenarios, these effects of low-O 2 are beneficial, including the control of radicle length (Polking et al, 1994). If the O 2 concentration were too low, or if the exposure period were too long, seedlings could develop irreversible abnormalities.…”

mentioning

confidence: 99%

“…Low concentrations of O 2 (1% to 2%) suppressed radicle length of impatiens, but the recommended exposure time (12 to 24 h) was brief because longer exposures evoked more seedling abnormalities (Polking et al, 1994). A study of longer exposures to low-O 2 concentrations that focuses on maintaining seedling health is needed.…”

mentioning

confidence: 99%

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Hypoxia Controls Hypocotyl and Radicle Length in Germinated Impatiens Seeds

Waterland¹,

Gladon²

2009

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Sowing germinated seeds for bedding plant production can decrease the production time and reduce profit losses from sporadically or poorly germinating seeds. Low concentrations of O2 have been used to control radicle length in Impatiens wallerana Hook. F., but only a brief exposure period could be used (12 to 24 h). The effects of prolonged exposures are unknown. Our first objective was to determine if impatiens seedlings could be acclimated to an extreme hypoxic environment by a preliminary exposure to a less severe hypoxic exposure. Our second objective was to determine the effects of longer-duration (greater than 24 h) treatments at low-O2 concentrations on hypocotyl and radicle length, abnormal seedling development, and subsequent plant growth and development. Our third objective was to provide a commercial recommendation of a low-oxygen treatment or treatments that could be used for temporary storage of unused germinated seeds. Germinated seeds were placed in various combinations of 0.5%, 1.0%, and 1.5% O2 for either 4 days (Expt. 1) or 3 days (Expt. 2) followed by 24 h in air to simulate shipping. Germinated seeds were less tolerant of 0.5% O2 than greater O2 concentrations, especially during the first 2 days of treatment, and more abnormal seedlings developed at 0.5% O2. Germinated seeds were more tolerant of 0.5% O2 during Days 3 and 4 of the treatment period or when days at 0.5% O2 were interspersed between days of 1.0% or 1.5% O2. This indicates that germinated impatiens seeds can tolerate extremely low-O2 for longer durations (greater than 24 h) when first acclimated to lower O2 concentrations. Treatment of 1.5% O2 for Days 1 and 2 followed by 0.5% O2 for Day 3 is recommended for commercial use. Hypocotyl and radicle length was controlled to 1 mm without development of abnormal seedlings. Fully grown plants from seedlings that received low-O2 treatments were not different from control plants with regards to hypocotyl and radicle length, percentage abnormal seedlings, and plant growth and quality, ensuring there were no long-term detrimental effects.