| More recently, NEWTON-BARBER and NETTING (1968) resumed the problem applaying
an up to date more complete approach comparing genetic constitution of lines
of wheat with chemical composition of waxes, paying particular attention
to the amount of Beta-dicarbonyl
compounds present in the wax. The authors were able to demonstrate that both the glaucous and non-glaucous lines are waxy and the phenotypical differences depend on the presence of Beta-diketones and hydroxy Beta-diketones on the glaucous lines. We have resumed the subject on the relationships between genetical constitution and chemical composition of the wax, taking advantage of the availability of ditelosomic lines developed in Triticum aestivum var. Chinese Spring by SEARS (1954). As well known, each ditelosomic line carries a homozygous deletion for a particular chromosome arm. Any morphological and chemical variation detected in the ditelosomic line can be related with the specific missing arm of the chromosome. Because of the comple xity of the analysis required for a complete analysis of all the components of the wax, we have made a preliminary screening on the alkane fractions of Chinese Spring variety and of 29 derived ditelosomic lines. Materials and Methods Plants of Triticum aestivum variety Chinese Spring and of 29 derived dictelosomic lines kindly supplied by Dr. LAW (Cambridge, England) were grown in the open in the Po Valley near Milan during 1976. The plants were collected at the stage of maximum wax production when the flag leaf was completed and the spike was emerging from the sheath (late boot stage). Wax extraction was carried out by dipping the shoots into chloroform for approximately 60 sec. Evaporation of the solvent under reduced pressure in the rotary evaporator gave the derived wax sample. Each extracted material was chromatographed over a silica gel column (with carbon tetrachloride for 7A-L, 7D-S and the parent plants, while cyclohexane was used for the remaining lines) to obtain the n-alkane fraction as a colourless crystalline substance. IR absorption bands : vmax 2920, 2860, 1460, 1385, 730 and 720 cm-1. The gas chromatograms were taken on a Carlo Erba mod. 2400 FID type attached with a glass column (2 m x 3 mm) packed with 100-120 mesh GCP coated with 1% silicone OV1, 5C/minute programmed temperature from 160C to 270C and 30 ml/minute flow rate of N2 carrier gas. Authentic samples of alkanes were used as standards. |
| <-- Back | | | --> Next |