SULFUR CONTENT AS A SCREENING CRITERION FOR METHIONINE AND CYSTEINE LEVEL IN PEA SEEDS

PNL Volume 12 1980 RESEARCH REPORTS 41

SULFUR CONTENT AS A SCREENING CRITERION FOR METHIONINE AND CYSTEINE LEVEL

IN PEA SEEDS-/

Krzywinska, F., Plant Breeding 6; Acclimatization Inst., Poznan, Poland

Przybylska, J., and J. Hurich Polish Academy of Sciences, Poznan, Poland

The content of total protein, total sulfur (TS), sulfate sulfur (S-SO₄),

methionine and cysteine (1/2 cystine) was determined in 25 seed samples

representing diverse forms of Pisum, ranging from primitive to cultivated.

The sulfur content was determined by the nephelometric method, described in

the paper to be published in "Hodowla Roslin, Aklimatyzacja i Nasiennictwo"

(a Polish journal, "Plant Breeding, Acclimatization and Seed Production").

The level of sulfur-containing amino acids was determined by an automatic

amino acid analyzer. Results concerning the difference between the contents

of total and sulfate sulfur ("TS - S-SO₄") and data obtained for the content

of sulfur of sulfur-containing amino acids (S-SAA) were statistically analyzed.

The analysis showed that the contents of S-SAA and "TS - S-SO₄" form

similar patterns. The correlation between the contents of S-SAA and

"TS - S-SO₄" proved to be stronger (r=0.93**) than that between the contents

of S-SAA and TS (r=0.78**). It should be stressed that the level of "TS - S-SO₄"

was very close to that of S-SAA, averaging 6% higher. From these results

it may be inferred that in the preliminary screening of pea breeding materials

for sulfur-containing amino acids (which limit the nutritional value of seed

protein of legumes) a quantitative analysis of methionine and cysteine may

be substituted by determination of the contents of total and sulfate sulfur.

A negative correlation was found between the protein content in the seed

and the proportion of sulfur-containing amino acids in protein.

This work was performed under Government Project PR-4