Chiscon, J. A.
Using undamaged leaves from mature field plants, I determined chlorophyll content for several chlorophyll mutants, a single anthocyaninless mutant (af), and the wild-type lines from which the mutations were obtained. Methods for the preparation of chlorophyll suspensions, extraction of chlorophyll, and determination of chlorophylls a and b were adaptations of methods described by Gorham, by Vishniac, and by Mackinney (Colowick, S. P. and N. O. Kaplan. 1957. Methods in Enzymology. Academic Press, Inc. 4:342-343). The stocks are irradiation-induced mutants from the laboratory of A. B. Burdick. Line 018 is a red cherry; 226 and 215 are identical autodiploids of L. pimpinellifolium; Kokomo is a commercial variety of L. esculentum. The mutants are listed immediately after the wild-type line in which they were induced. All of the mutants are homozygous viable and fertile.
None of the tested plants lacked either chlorophyll a or b. Chlorophyll reductions of greater than 50%, however, were found in the yg\2, yg\3, yg\4, yg\5, and yg\6 mutants. The yg\5 mutant exhibited the most severe chlorophyll loss, having only 17.5% of the chlorophyll a and 11.9% of the chlorophyll b content of the 018 wild type.
The mutants appear to fall into 3 groups with respect to chlorophyll ratio. The af, md, nd, yg\3 and yg\4 mutants retain much the same proportion of chlorophyll a to b as the wild types. The pg, pg\2, pg\3.li and sy mutants contain proportionally less chlorophyll a than wild types. The sy mutant, although it contains 83.7% of the chlorophyll b content of the wild type, has only 60.6% of the chlorophyll a content. The third group, consisting of the yg\2, yg\5 and yg\6 mutants, contains proportionally less chlorophyll b than wild type. The yg\2 mutant contains 33.8% of the chlorophyll a content of the wild type but only 19.1% of the chlorophyll b content.
Double mutants examined for chlorophyll content show a variety of relationships to the single mutants. Generally, if one mutant is associated with much, but the other with little chlorophyll loss, the chlorophyll content of the double mutant tends to resemble the former. If both mutants, however, are associated with substantial chlorophyll loss, the double mutant has less chlorophyll than either of the two.
Five double mutants involving the yg\2 character were examined. In 4 of these the chlorophyll b content remained essentially that of the yg\2 mutant. In the yg\2 md mutant, however, there was an increase in chlorophyll b to 0.23 mg/g--a point part way between the respective chlorophyll b contents of the md and yg\2 mutants alone. The content of chlorophyll a in the double mutant was essentially that of the yg\2 mutant.
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Chlorophyll Per cent
Line (mg/g fresh leaf material) chloropbylls
or __________________________ Ratio ____________
mutant a b a + b a/b a b
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018 1.50 0.69 2.18 2.18 68.5 31.5
af 1.42 0.69 2.10 2.06 67.3 32.7
md 1.17 0.59 1.76 2.00 66.6 33.4
yg\5 0.26 0.08 0.34 3.18 76.1 23.9
yg\6 0.49 0.18 0.67 2.69 72.9 27.1
pg\2 1.19 0.72 1.91 1.66 62.4 37.6
li 1.15 0.67 1.82 1.73 63.3 36.7
pg\3 1.14 0.68 1.82 1.67 62.5 37.5
226;215 1.37 0.75 2.12 1.84 64.8 35.2
nd 1.06 0.54 1.61 1.95 66.1 33.9
yg\2 0.46 0.14 0.61 3.24 76.4 23.6
Kokomo 1.38 0.62 2.00 2.22 69.0 31.0
yg\3 0.63 0.32 0.94 1.96 66.3 33.7
yg\4 0.54 0.25 0.79 2.19 68.6 31.4
sy 0.84 0.52 1.36 1.61 61.7 38.3
pg 0.83 0.50 1.32 1.67 62.5 37.5
yg\3 ; nd 0.50 0.21 0.71 2.37 70.3 29.7
yg\3 ; yg\5 0.28 0.10 0.37 2.81 73.7 26.3
yg\2 ; yg\3 0.38 0.15 0.54 2.48 71.3 28.7
yg\3 ; yg\4 0.48 0.22 0.70 2.20 68.7 31.3
li ; yg\2 0.46 0.14 0.69 3.32 76.8 23.2
yg\2 ; yg\6 0.39 0.16 0.55 2.38 70.4 29.6
yg\2 ; md 0.47 0.23 0.70 2.04 67.1 32.9
nd ; md 0.87 0.44 1.31 1.98 66.5 33.5
yg\2 ; nd 0.41 0.17 0.58 2.39 70.5 29.5
af ; nd 1.07 0.58 1.65 1.84 64.8 35.2
pg\3 ; md 1.12 0.66 1.78 1.70 63.0 37.0
pg\3 ; md 0.48 0.18 0.65 2.67 72.7 27.3
yg\6 ; md 0.48 0.17 0.66 2.77 73.5 26.5
li ; md 0.48 0.17 0.65 2.92 74.5 25.5
pg\2 ; md 1.17 0.58 1.75 2.02 66.9 33.1
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