Direct Application of Ninhydrin Reagent Solution to Exposed Maize Endosperm to Screen for Protein Mutants
- Hugo L. Zorilla and
- Paul L. Crane2
The “ninhydrin reagent solution” chemically reacts with the free amino acids present in the exposed maize (Zea mays L.) endosperm to produce a blue color. This study utilized that reaction to search for new mutants and also tested the effectiveness of the use of ninhydrin reagent solution applied to exposed maize endosperm of known opaque-7 material.
In the search for new mutants, 300 kernels each of 55 collections of maize were tested. In general, there was a lack of ninhydrin penetration on vitreous kernels, but there were exceptions. Sources with floury endosperm type, or a soft crown or “cap” showed good ninhydrin penetration. Lysine content of positive reacting kernels was at the normal level, but protein showed a tendency to higher levels.
Ears of a population with families segregating for opaque-7 were used to test the practical effectiveness of this ninhydrin technique for mutant screening. Homozygous opaque-7 testers were used to verify the presence of the opaque-7 gene. Ears with kernel moistures of 15.6 to 44.1% were tested, but higher moisture levels did not facilitate the penetration of the endosperm tissue by the ninhydrin reagent. In fact, moistures above 35% tended to inhibit the reaction.
Some of the numerous deviations from expectation in this experiment were apparently due to a variety of modifier genes not only masking the opaque-7 phenotypic expression in varying degrees, but also altering levels of free amino acids. The potential effectiveness of the ninhydrin test in locating any new high lysine mutant would be limited by any interaction between that mutant gene and its genetic background which reduced the level of free amino acids.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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