Optimizing the calcium content of a copolymer acrylamide gel matrix for dark-grown seedlings.
A copolymer acrylamide acrylate gel was investigated as the sole root matrix for dark-grown seedlings of soybean (Glycine max Merr. 'Century 84'). Increasing Ca2+ in the hydrating solution of the hydrogel from 1 to 10 mM decreased its water-holding capacity from 97 to 46 mL g-1, yet water potential of the medium remained high, sufficient for normal plant growth at all Ca2+ concentrations tested. Elongation rate of dark-grown soybean seedlings over a 54-hour period was 0.9, 1.5, and 1.8 mm h-1 with 1.0, 2.5, or 5.0 mM Ca2+, respectively, but did not increase with further increases in Ca2+ concentration. Further study revealed that Na+ was released from the hydrogel medium and was taken up by the seedlings as Ca2+ increased in the medium. In dry hypocotyl tissue, sodium content correlated negatively with calcium content. Despite the presence of Na+ in the hydrogel, seedling growth was normal when adequate Ca2+ was added in the hydrating solution. Acrylamide hydrogels hold good potential as a sole growth matrix for short-term experiments with dark-grown seedlings without irrigation.
Myers
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PN
Purdue University, Department of Horticulture, West Lafayette, IN 47907-1165, USA.
Mitchell
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CA
D000178:Acrylamides / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D002118:Calcium / Q000378:metabolism*; D003470:Culture Media; D003624:Darkness; D018546:Hypocotyl / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism*; D011108:Polymers; D013025:Glycine max / Q000378:metabolism; D014867:Water / Q000378:metabolism
D000178:Acrylamides; D000538:Aluminum Silicates; D003470:Culture Media; D011108:Polymers; D014867:Water; C003760:vermiculite; D002118:Calcium