Ecological Relationship of the Agropopulations of Ecdysteroid-Containing Plants Rhaponticum carthamoides (Willd.) Iljin and Serratula coronata L. with Insects-Phytophagans Part 2. Variability of the Composition of Phytoecdysteroids in Agrocoenosis and their Role in Damageability of Plants by Pests
N. P. Timofeev
Keywords: Rhaponticum carthamoides, Serratula coronаta, phytoecdysteroids, 20-hydroxyecdysone, ecdysone, insects-pests, cultivation conditions
Pages: 827-842
Abstract
Accumulation and variability of ecdysteroids in the phytomass, which are analogs of the insect moulting hormones, were studied in ontogenesis of the agropopulations of Rhaponticum carthamoides (Leuzea carthamoides DC.) and Serratula coronаta, with relation to the age and plant cultivation conditions. The physiological role of ecdysteroids in the ecological mutual relations with pests was evaluated.
It was revealed that the enhancement of the activity of phytophagans coincides with biochemical changes in the composition of ecdysteroids, possessing various kinds of physiological activity, and is accompanied by damage of reproductive organs. During the age-related changes in ontogenesis and seasonal development during the vegetative period, the individual share of physiologically active ecdysteroid 20-hydroxyecdysone decreases, while the low-activity ecdysteroids inokosterone and ecdysone are accumulated in generative sprouts.
Concentrating of the low-activity ecdysteroid ecdysone in the phytomass is affected by the ecological conditions of the environment and anthropogenic factors of cultivation. The factors promoting realization of the potential of affection by pests are the microclimate of the environment, accommodation of populations over the relief elements of the area, and the performed agrotechnical actions (intensity of phytomass removal, superfluous humidity in the rooting layer of populations).
The work was done under partial financial support granted by the administration of the Arkhangel'sk Region and the Russian Foundation for Basic Research (RFBR) NN 08-04-98840, 03-04-96147.
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