Tentative determination of the molecular weight of substances stimulating the flowering of winter wheat

Biesaga-Kościelniak, J.; Dubert, F.; Marcińska, I.; Kościelniak, J.

Tentative determination of the molecular weight of substances stimulating the flowering of winter wheat

1998

Biesaga-Kościelniak, J. | Dubert, F. | Marcińska, I. | Kościelniak, J.

Murashige & Skoog nutrient was supplemented with substances of molecular weight (MW) less than 5 kDa, which were separated from extract of winter wheat ears by means of Sephadex G-25 ultrafiltration. Isolated embryos of the same wheat cultivar (Grana) were vernalized in the nutrient for 0 and 7 days at 2 °C for 2 weeks and planted in a glass-house. After 150 days of growth (20/17 °C day/night) the development of the shoot apices was observed. It was found that substances of MW<5 kDa strongly stimulated the generative development of the plants, enabling the earing of 30 % of non-vernalized plants (control=0%) and 100 % plants vernalized for 7 days (control=29 %).The substances present in the extract of both spring (cv. Jara) and winter (cv. Grana) varieties were fractionated by means of Sephadex chromatography into 300 fractions of MW=1 to 5 kDa and each of them was added to the isolated embryos of cv. Grana. The embryos were vernalized at 2 °C for 7 days and then cultured as previously described. It was found that the differentiation of the shoot apices was stimulated by over 34 % by fractions of winter wheat extract and more than 50 % by fractions of the spring wheat extract. However, only a few of identical fractions of the extracts of both wheat varieties were able to induce the earing of the plants. These fractions were grouped in 4 continuous intervals of MW equal to about 4.5–4.9, 3.2–3.3, 2.1–2.6 and 1.00–1.03 kDa. Within the three intervals was identified a small group of identical fractions, which affected the growth of the seedlings in similar mode i.e. inhibiting or stimulating. Thus it can be assumed that these intervals contained identical or similar substances capable of stimulating strongly the earing of winter wheat.

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