Hypoxia Controls Hypocotyl and Radicle Length in Germinated Impatiens Seeds

Abstract

<jats:p>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 O<jats:sub>2</jats:sub> have been used to control radicle length in <jats:italic>Impatiens wallerana</jats:italic> 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-O<jats:sub>2</jats:sub> 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% O<jats:sub>2</jats:sub> 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% O<jats:sub>2</jats:sub> than greater O<jats:sub>2</jats:sub> concentrations, especially during the first 2 days of treatment, and more abnormal seedlings developed at 0.5% O<jats:sub>2</jats:sub>. Germinated seeds were more tolerant of 0.5% O<jats:sub>2</jats:sub> during Days 3 and 4 of the treatment period or when days at 0.5% O<jats:sub>2</jats:sub> were interspersed between days of 1.0% or 1.5% O<jats:sub>2</jats:sub>. This indicates that germinated impatiens seeds can tolerate extremely low-O<jats:sub>2</jats:sub> for longer durations (greater than 24 h) when first acclimated to lower O<jats:sub>2</jats:sub> concentrations. Treatment of 1.5% O<jats:sub>2</jats:sub> for Days 1 and 2 followed by 0.5% O<jats:sub>2</jats:sub> 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-O<jats:sub>2</jats:sub> 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.</jats:p>

Modified atmosphere packaging of green gram (Vigna radiataL.) sprouts for extending shelf life and acceptance in indian market

“…Maximum sprout length was obtained in bags with two microperforations and was significantly different than those packed in non perforated bags. Hypoxia controls the radicle length in many germinating seeds, as oxidative phosphorylation is the major m echanism that produces ATP for m etabolic activities in germinating seeds (Waterland and Gladon, 2009). It is logical to infer that very low levels of oxygen in the non perforated bags especially in the initial days of storage had slowed down the process of radicle elongation, and the reverse process had happened in bags with two micro perforations.…”