Cytogenetic and molecular characterization of almond trees treated with plant biostimulants or boron-based fertilizers

Abstract

benefits to human health, and its consumption has been increasing in the last years, requiring an increased production. P. dulcis is a Mediterranean crop with high adaptability

Assessing the Effect of Plant Biostimulants and Nutrient-Rich Foliar Sprays on Walnut Nucleolar Activity and Protein Content (Juglans regia L.)

“…The leaves were collected and immediately fixed in acetic ethanol (3:1, v/v). Upon transport to UTAD, the fixed leaves were maintained at −20 • C until the preparation of chromosome spreads using the procedure described by [24].…”

“…Therefore, the cytogenetic analysis of mesophyll cells under environmental constraints or treatments with various products can reveal how external stimuli impact leaves on a cytological level. Examining the mesophyll cell cycle in interphase and dividing cells of grapevine and almond revealed the effects of abiotic stress and/or the selection of the best leaf treatment [24][25][26][27]. Nevertheless, angiosperm species have chromosomes with a reduced size, which makes cell cycle analysis difficult.…”

“…The staining of mitotic preparations with silver nitrate is required to study the transcriptionally active nucleoli. The staining of nucleoli and nucleolar organiser regions (NORs) with silver nitrate in interphase and metaphase cells, respectively, enables the analysis of RNA (rRNA) gene expression, which influences the ribosomal production and rate of protein synthesis [24][25][26][27]. However, the reduced chromosome size of angiosperm species impairs NOR visualisation.…”

“…However, the reduced chromosome size of angiosperm species impairs NOR visualisation. Nonetheless, the study of nucleolar activity in plants constitutes a fast approach to assess cytotoxicity caused by abiotic stresses in grapevine [25][26][27] or excess of micronutrients used in bread wheat seed biofortification [29], as well as to evaluate the suitability of foliar treatments [24,25], including biostimulants and boron-based fertilisers, performed in Prunus dulcis (almond) [24]. Nucleolar activity analysis has been used to verify how the induced abiotic stress impacts the nucleolar size, morphology, and number of different plant species [24][25][26][27][29][30][31][32][33].…”

“…Nonetheless, the study of nucleolar activity in plants constitutes a fast approach to assess cytotoxicity caused by abiotic stresses in grapevine [25][26][27] or excess of micronutrients used in bread wheat seed biofortification [29], as well as to evaluate the suitability of foliar treatments [24,25], including biostimulants and boron-based fertilisers, performed in Prunus dulcis (almond) [24]. Nucleolar activity analysis has been used to verify how the induced abiotic stress impacts the nucleolar size, morphology, and number of different plant species [24][25][26][27][29][30][31][32][33]. With this in mind, for the present study, we hypothesised that the tested products (biostimulants and mineral-rich foliar sprays), certified for use in organic farming, can induce a stable nucleolar activity and improve the number of total soluble proteins of walnut trees, cv.…”