Рост и развитие пыльцевой трубки можжевельника обыкновенного (Juniperus communis): роль ядра клетки трубки

Abstract

In this work we have tried to explain the functional value of the tube cell nucleus and its relationship with the structures of the pollen tube on the example of juniper. Juniper pollen tubes were studied in vitro by the methods of light microscopy (transmitted light, fluorescence) and Fourier-transform infrared (FTIR) spectroscopy. A brief description of the growth and development processes of juniper pollen tubes is given. The experiments on the enzymatic destruction of the pollen tube wall revealed the relation between the generative nucleus and the protoplast associated with the tube cell nucleus. The generative nucleus is quite frmly connected with the protoplast of the tube cell nucleus by means of the surface tension of internal membranes. It was proven that the protoplast and the both nuclei save their integrity outside the tube body. That is, they retain their viability outside the tube body for some time after lysis the tube tip. However, both the generative nucleus and the tube cell nucleus cannot function independently outside the protoplast of the pollen tube. Microfbrils of the actin cytoskeleton are distributed irregularly inside the tube. Most of them are concentrated in the central part of the tube and associated with the tube cell nucleus and protoplast. Leucoplasts predominate in the composition of plastids. The majority of them are amyloplasts, the better part of which is concentrated around the tube cell nucleus and protoplast. Protoplast contains a large number of mitochondria. Lysosomes are distributed over the entire volume of the pollen tube more or less regularly. However, a signifcant part of lysosomes, especially in actively growing tubes, accumulates around the tube cell nucleus and near the tube tip. The use of deuterium as a marker allowed to establish the sequence of synthesis and localization of synthesized substances during the pollen tube growth. The increased deuterium content was observed in the zone of the protoplast associated with the tube cell nucleus. The obtained experimental data allowed to suggest that the tube cell nucleus likely controls the synthesis of organic substances and their distribution in the tube body. Probably, the tube cell nucleus promotes its polar growth and orients the growth of the tube tip in vivo in time and space. For citation: Surso M.V., Chukhchin D.G. Growth and Development of Pollen Tubes in Common Juniper (Juniperus communis): The Role of the Tube Cell Nucleus. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 2, pp. 20–34. DOI: 10.37482/0536-1036-2020-2-20-34 Funding: The study was carried out with the fnancial support from the Russian Foundation for Basic Research within the framework of the research project No. 18-04-00056. Pullen samples were collected during the expedition work within the framework of the research on the state assignment of the Russian Academy of Sciences (topic No. 0409-2019-0039), state registration No. АААА-А18-118011690221-0. Acknowledgments: This research was performed using the equipment of the Core Facility Center “Arktika” of the Northern (Arctic) Federal University named after M.V. Lomonosov.