ISSN 1021-4437, Russian Journal of Plant Physiology, 2007, Vol. 54, No. 6, pp. 845–852. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © V.N. Khryanin, 2007, published in Fiziologiya Rastenii, 2007, Vol. 54, No. 6, pp. 945–952.
FORMULATING THE THEORY
OF SEX DIFFERENTIATION IN PLANTS
Sex determination and reversal in plants are poorly
investigated issues of developmental biology, although
their theoretical and practical signiﬁcance is very great.
It depends on possible prospects for breeding and prac-
tical plant growing associated with the understanding
of sex expression in plants. In this relation, Vavilov 
wrote that the investigation of sex and determination of
type diversity are of decisive importance for working
out the methods of breeding and should be made in all
main crops. A prominent biologist Grant  noted the
importance of investigating the sex process in plants
and their reproduction for understanding the evolution
of individual taxa. Sabinin  believed that it is hardly
possible to ﬁnd, among the known stages of develop-
ment, a more important stage than sex determination.
Therefore, it is clear that the works on plant sexualiza-
tion are of general importance.
Sabinin’s colleagues Minina, Guseva, and Satarova
investigated the effect of external factors (mineral
nutrition and ambient gas composition) on the transfor-
mation of sexual characters in plants [4, 5]. A key role
in the elucidation of the mechanisms of plant sexualiza-
tion belongs to the works of Molotkovskii [6, 7], who
considered them in relation to polarity in the develop-
ment of the plant organism. Dzhaparidze [8, 9] and
Sidorskii  thoroughly reviewed the evolution of sex
differentiation as well as physiological and biochemi-
cal aspects of this issue.
The path of investigation of sex evolution in plants
was long and thorny. A stone monument made about
900 B.C. and found in Egypt presumably shows the
Based on the lecture given to the students and young researchers
at the annual meeting of the Russian Society of Plant Physiolo-
gists, October 2–6, 2006, Rostov-on-Don.
scenes of pollination of a date palm conducted by shak-
ing the male inﬂorescences over the tree. Apparently, in
ancient times people were aware that certain plants of
the same species produce ﬂowers of different types
(genders). In medieval Russia (A.D. 900–1200), people
were also aware of the existence of 2 plant genders and
understood their speciﬁc features. They differently
called pistillate and staminate specimens of hemp.
Empedocles (485–425 B.C.), Aristotle (384–322 B.C.),
and his disciple Theophrastus (370–286 B.C.) were the
ﬁrst to describe in their treatises [11, 12] the existence
of plant sex, a direct relationship between the ﬂower
and fruit formation, and revealed a similarity between
reproduction in plants and animals. A notable contribu-
tion to the understanding of gender issue was made by
Camerarius  who discovered sex differentiation in
plants, Linnaeus [14–16], who formulated a notion
about sexual system of plants, and Kolreuter [17, 18],
who proved the existence of sex in plants on the basis
of the experiments that he conducted at St. Petersburg
Botanical Gardens. When a Russian researcher
Navashin  discovered the process of dual fertiliza-
tion in angiosperms, the interest to the sex issue became
MAJOR PATHWAYS OF SEX EVOLUTION
Evolution of plant kingdom and animal world was
associated with the evolution of the types of reproduc-
tion of the organisms. Sexual reproduction became the
most advanced form of reproduction in organic world.
The signiﬁcance of the sex process in phylogenesis
depends on the fact that, as a result of fertilization, the
organisms with double heredity are produced, which
ensures their greater resistance and promotes the ability
to adapt to permanently changing life conditions.
Evolution of the Pathways of Sex Differentiation in Plants
V. N. Khryanin
Department of Botany, Plant Physiology and Biochemistry, Belinskii State University, ul. Lermontova 37,
Penza, 440026 Russia;
fax: 7 (8412) 56-2566; e-mail: email@example.com
Received January 9, 2007
—The stages of formulating the theory of sex evolution, determination, and expression in plants were
brieﬂy reviewed. The role of phytohormones in sex differentiation in dioecious and monoecious plants was ana-
Key words: plants - evolution - differentiation - sex dimorphism - apomixis - phytohormones - gibberellins -