Gigantism in Nicotiana tabacum and Its Alternative Inheritance

Abstract

WITHIN recent years observers working with different varieties of Nicotiana tabacum grown commercially in the United States and elsewhere have recorded the sudden appearance of occasional giant plants of abnormally high leaf number. Except in height and number of leaves, which may be increased several times above the usual number, these giant plants in general appearance do not depart widely from the varietal type from which they took their origin. The great increase in number of leaves, together with a greatly elongated main stem, is accompanied bv a period of vegetative vigor of such long duration that blossoming does not normally take place when the plants are growing in the field. In order to obtain seed from such plants, the usual practise has been to transplant the roots and stub, or even the plants entire, to the greenhouse in the fall, where vegetative vigor is resumed with the final production of normal blossoms and seed during the winter. Plants of this habit of growth have been recorded in the Sumatra, Maryland. Cuban and Connecticut Havana types of tobacco. OCCURRENCE OF GIGANTISM IN DIFFERENT VARIETIES The first published record of gigantism in tobacco appears to have been made in 1905 by Hunger (1905), working with tobacco in Sumatra in connection with an investigation of the mosaic disease. Garner (1912) mentioned a Maryland Mammoth type, the origin of which was associated with a cross between two common varieties of Marvland tobacco. Hayes and Beinhart (1914) reported the occurrence of 218

The tomato FT ortholog triggers systemic signals that regulate growth and flowering and substitute for diverse environmental stimuli

“…Florigen-like systemic signals are expected to substitute for different environmental stimuli in diverse plant species. In a seminal discovery, Garner and Allard (26,27) identified a recessive mutation in the Maryland Mammoth (MM) tobacco strain that confers a short-day response on day-neutral tobacco plants. When grown under long days, cv.…”

Isolation of LUMINIDEPENDENS: a gene involved in the control of flowering time in Arabidopsis.

“…Genetic analyses have revealed that single gene differences can alter the flowering response type; for example, mutations that introduce or eliminate an effect of photoperiod Current address: Department of Horticulture, 1575 Linden Drive, University of Wisconsin, Madison, WI 53706-1590. * To whom correspondence should be addressed. on flowering have been described in tobacco (Allard, 1919), maize (Galinat and Naylor, 1951), pea (Murfet, 1989), sorghum (Quinby and Karper, 1945), and Arabidopsis (Rbdei, 1962;Koornneef et al, 1991;Zagotta et al, 1992). A mutation in gibberellin biosynthesis has recently been shown to inhibit the ability of Arabidopsis to flower in noninductive photoperiods (Wilson et al, 1992).…”

NFL, the tobacco homolog of FLORICAULA and LEAFY, is transcriptionally expressed in both vegetative and floral meristems.

“…In situ hybridizations were subsequently performed to identify more precisely the tissue in which steady state NFL transcripts accumulated. The short day-requiring cultivar N. tabacum cv Maryland Mammoth (Allard, 1919;Gebhardt and McDaniel, 1987) was used to control the developmental state of the plants from which shoot apices were harvested. Under the growth chamber conditions used, nine inductive short-day cycles are necessary and sufficient to induce flowering.…”