Seed productivity and features of biology of Malaxis monophyllos (L.) Sw. (Orchidaceae) on the northern distribution border
I.A. Kirillova, D.V. Kirillov
Section: Population ecology
The article presents the results of studying some aspects of Malaxis monophyllos (L.) Sw. (Orchidaceae) reproductive biology in the Komi Republic (northeast Russia), where the northern border of this species distribution area
passes. The research was carried out in 2010–2019 in the Syktyvdinskiy and Ust’-Kulomskiy administrative districts
of the Komi Republic. We have found that M. monophyllos usually occurs in wet forests and swamps, and sometimes
occupied the disturbed habitats with low competition (old forest motorways). It usually forms small coenopopulations
(up to 100 plants), with a high proportion of generative shoots. Within the coenopopulations, individual plants form
small groups or grow as single plants. The efficiency of pollination (46%) in the study area corresponds to the average
fruit set in the whole species distribution area. This parameter varies highly within one community, depending on
the weather and climatic conditions in different years. We found statistically significant negative correlation between
fruit setting and the number of seeds in fruit. So, the lower fruit set is compensated by numerous seeds in the fruit.
Seed productivity is high. In the Komi Republic, one fruit of M. monophyllos contains an average of 3338±219 seeds,
with more than 94% of seeds with embryo. The mean index of conditionally-real seed productivity (i. e. the mean
number of seeds per a generative shoot) is 53000 psc. In the Komi Republic, the seed productivity of M. monophyllos
was found to be higher than in the southern parts of its distribution area. It can be assumed that, in the northern part
of M. monophyllos distribution area, the increased number of seeds in the fruit is one of additional mechanisms of the
implementation of seed renewal, which is the main way of reproduction for this species. The seeds of M. monophyllos
are very small – 0.33–0.09 mm, and contain 88.4% empty air space, which provides them with volatility and increases
the chance to reach suitable places for germination.
Keywords: Malaxis monophyllos (L.) Sw., Orchidaceae, the Komi Republic, northern distribution border, fruit set, seed productivity