Premium
Boron deficiency alters cytosolic Ca 2+ concentration and affects the cell wall components of pollen tubes in Malus domestica
Author(s) -
Fang K. F.,
Du B. S.,
Zhang Q.,
Xing Y.,
Cao Q. Q.,
Qin L.
Publication year - 2019
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/plb.12941
Subject(s) - biology , malus , boron , pollen , cytosol , botany , cell wall , biophysics , biochemistry , enzyme , physics , nuclear physics
Boron (B) is essential for normal plant growth, including pollen tube growth. B deficiency influences various physiological and metabolic processes in plants. However, the underlying mechanism of B deficiency in pollen tube growth is not sufficiently understood. In the present research, the influence of B deficiency on apple ( Malus domestica ) pollen tube growth was studied and the possible regulatory mechanism evaluated. Apple pollen grains were cultured under different concentrations of B. Scanning ion‐selective electrode technique, fluorescence labelling and Fourier‐transform infrared ( FTIR ) analysis were used to detect calcium ion flux, cytosolic Ca 2+ concentration ([Ca 2+ ]cyt), actin filaments and cell wall components of pollen tubes. B deficiency inhibited apple pollen germination and induced retardation of tube growth. B deficiency increased extracellular Ca 2+ influx and thus led to increased [Ca 2+ ]cyt in the pollen tube tip. In addition, B deficiency modified actin filament arrangement at the pollen tube apex. B deficiency also altered the deposition of pollen tube wall components. Clear differences were not observed in the distribution patterns of cellulose and callose between control and B deficiency treated pollen tubes. However, B deficiency affected distribution patterns of pectin and arabinogalactan proteins ( AGP ). Clear ring‐like signals of pectins and AGP on control pollen tubes varied according to B deficiency. B deficiency further decreased acid pectins, esterified pectins and AGP content at the tip of the pollen tube, which were supported by changes in chemical composition of the tube walls. B appears to have an active role in pollen tube growth by affecting [Ca 2+ ]cyt, actin filament assembly and pectin and AGP deposition in the pollen tube. These findings provide valuable information that enhances our current understanding of the mechanism regulating pollen tube growth.