Flowering vernalization

Table 15.2 The influence of zearalenone on the generative development of nine winter wheat varieties. Isolated wheat embryos were cultured in sterile conditions on Murashige and Skoog (1962) media supplemented with 0 (control) and 2.00 mg/dm3 of zearalenone during 14 days at 5°C (vernalization). After this period, plants were transferred to soil and cultivated at 20/17°C. The number of heading and vegetative plants was fixed after 100 days from vernalization. The length of the phase from vernalization to flowering was determined in days...

Variety Number of plants Differentiation of frequency with respect to control Length of the phase from vernalization to flowering (days) ... 

Table 15.4 The influence of the inhibitor of zearalenone (malathion) on the generative development of winter wheat plants. Seeds of wheat cv. Grana were cultured at sterile condition on Murashige and Skoog (1962) media supplemented with 0 (control), melathion (10 ml/dm3) and zearalenone (2 mg/dm3) during 5 weeks at 5°C (optimal time of vernalization). After vernalization plants were replaced to soil and grown at 20/17°C. Percentage of headed plants and the length of phase from vernalization to flowering was determined for 100 plants in each kind of medium...

Mesterhazy A, Bartok T, Mirocha CG, Komoroczy R (1999) Nature of wheat resistance to Fusarium head blight and the role of deoxynivalenol for breeding. Plant Breed 118 97-110 Michales SD, Amasimo RM (2000) Memories of winter vernalization and the competence to flower. Plant Cell Environ 23 1145-1153... 

Promote bolting and flowering in non vernalized biennials and in long-day plants... 

In this experiment too, AA and AS6 contents of vernalized embryo-axis and endosperm were higher But not so markedly Because N.P 718 was an early flowering spring cultlvar ... 

The far reaching inductive effects of vernalization and that of the following photoperiod on the growth and flowering response of long day plants observed by Pandya (1969) is supported by the findings of a number of earlier workers (Chinoy, 1962 Chinoy and Nanda, 1951, 1951 a, b 1952 Chlnoy et al., 1959 Chinoy and Mansuri, 1966 Mansuri, 1965 Nanda et al., 1959 Sirohi et al., 1959 Sawhney et al., 1959 Raj, 1971 Vyas, 1971 Patel, 1967 Shah, 1974 ... 

It was found that the rates of synthesis of AA and AS6 were considerably enhanced by long photoperiod and vernalization treatment in both the early CE) and late CL) flowering genotypes of wheat CChlnoy, 1970). The rate of synthesis of AA was higher and that of ASG lower in the early genotype under normal day control CNDC) compared to those in Bledsoe (L) under the same environment (Chinoy et al., 1969 b). 

In addition to our winter cereals many other winter annuals (page 253) and biennials (two-year plants) are dependent on vernalization. In many cases the biennials form a rosette of leaves which is attached to the soil in the first year with which they pass the winter. In the second year when the days become long enough shoots sprout forth and flowers are formed. 

A further question concerns the site at which low temperature treatment acts. Information on this point was obtained from cultures grown on artificial nutrient media. Not only can isolated embryos be vernalized on defined media but vernalization can also be successfully carried out on isolated shoot tips. Plants capable of flowering can regenerate from shoot tips that have been subjected to low temperature. In the case of Petkus rye the apical meristem is the receptor site for low temperature treatment. Now of course this is not the case with all plants as we shall see. 

The longer rye is vernalized the more quickly it flowers. Only after vernalization has lasted for about 20 days is a further extension of vernalization not accompanied by a shortening of the time taken to flower (Fig. 231). Thus, apparently during vernalization processes occur which proceed step by step and finally lead to a specific end product. The more of this end product that is present the more quickly the plant is induced to flower after completion of vernalization. 

An annual and a biennial breed of Hyoscyamus nigerMQ known. The annual flowers in the same year in which it is sown. In the first year the biennial forms only a rosette of leaves that is attached to the soil and with which it passes the winter. After vernalization brought about by the cold of winter it forms flowers in the second year provided that the days are long enough (Fig. 232). Long days prevail in our latitudes in the summer. The difference between the annual and biennial breeds has also been shown to be genetically determined. Of the many facts discovered first by... 

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