Differential identification of natural forms of indolyl-3-acetic acid

An original micromethod ELISA for differential quantitative determination of free (indolyl-3-acetic acid) and bound (indolyl-3-acetyl-L-aspartic acid) forms of auxins is suggested. Our immunoassay approach is basic and may be applied to problems in biology, medicine, agriculture, and environmental protection for the identification of low-molecular compounds related in chemical structure and characterized by different biological activity.     

Comparative analysis of the spatiotemporal distribution of endogenous hormones in the ovaries of wheat and dandelion in the period of ovule activity

New data are reported on the spatiotemporal distribution of free and bound forms of phytohormones (cytokinins, auxins, abscizins) in the ovaries of the amphimictic species Triticum aestivum L. and the apomictic species Taraxacum officinale Web. The data are attributed to four domains of the ovary and three intervals composing the period of ovule activity (from the moment of the ovule at relative rest to the moment of the ovule at the first division). The data were obtained by modifications of the ELISA method. The modifications were elaborated for each phytohormone. Comparative analysis of the data implies that basic events of the reproduction process in the ovary in the period of the ovule activity are under the endogenous hormonal control system. The distributions of free and bound forms of phytohormones in the ovaries of two species show both common regularities, probably characteristic of amphimicts and apomicts, and special features. The latter may be related to the specificity of the reproduction type.     

A New Method for Differential Quantitative Assay of Zeatin and Zeatin Riboside

A new method is proposed for differential quantitative assay of two major endogenous cytokinin forms. It is based on determination of two effective parameters—concentrations of zeatin and zeatin riboside—with the use of appropriate antigens as standards. The method can be used for determining cytokinins in small samples of plant tissues without extract fractionation. This study pioneers the quantitation of changes in the hormonal status of ovules and ovaries of Triticum aestivumL. at early stages of embryogeny. A gradual increase in the content of the active and storage forms of the hormones from the ovary to the ovule was revealed.     

Spatial and temporal distribution of free and bound ABA in wheat and dandelion ovaries in the period of egg-cell activity

We quantified endogenous free and bound ABA in ovaries of the apomictic Taraxacum officinale Web. (dandelion) and amphimictic Triticum aestivum L. (wheat) species. ABA distribution was assessed in four ovary sections and during three developmental stages: from the quiescence release of the egg-cell until its first division (the period of egg-cell activity). ABA content was determined by the novel modification of the ELISA technique. The ovaries of both species contained approximately similar amounts of free ABA; whereas wheat ovaries contained 1.5 to 2-fold more bound ABA. A possible involvement of the hormonal system in the control of the chronology of the basic events of plant reproduction (egg-cell activation, the onset of endosperm development, the start of embryogenesis) is discussed.     

Differential analysis of major natural cytokinins by enzyme immunoassay

An immunochemical method for quantitative differential analysis of major types of natural cytokinins in plant tissues subjected to minimal treatment, without purification or chemical modification of hormones, is proposed. This method is recommended for use in biology, medicine, and agriculture for determination of low-molecular-weight compounds having similar chemical structures but various biological activities.     

Immunoenzyme method for differential assay of free and bound ABA

We performed the immunochemical study of two solid-phase competitive ELISA systems differing in their specificity toward free and bound ABA. A possible application of these systems for the quantification of natural ABA forms without their preliminary separation and purification in a single sample of plant material was demonstrated.     

Spatial and Temporal Distribution of Zeatin and Zeatin Riboside during the Period of the Egg-Cell Activity in the Ovaries of Amphimictic and Apomictic Plants

Spatial and temporal distribution of zeatin and zeatin riboside was studied in the ovaries of amphimictic (Triticum aestivum L.) and apomictic (Taraxacum officinale Web.) species during the period from the quiescence release of the egg cell to its first division. This period was divided into three stages: (1) no signs of division of the central cell, (2) division of the central cell and no signs of division of the egg, and (3) division of the egg. Cytokinin content was determined in ovary and its four sections (basal, medial, apical, and ovule) using an original modification of ELISA. Apomicts and amphimicts were shown to be similar in the pattern of changes in the cytokinin content in basal and medial zones but differed substantially in that of apical section and ovule.