Morphometric and biochemical screening of old mulberry trees in the former sericulture region of Slovenia

• Published in: Acta Societatis Botanicorum Poloniae 2019-01, Vol.88 (1), p.1
• Main Authors: Krajnc, Andreja Urbanek, Ugulin, Tina, Pausic, Andrej, Rabensteiner, Johannes, Bukovac, Vesna, Petkovsek, Maja Mikulic, Janzekovic, Franc, Bakonyi, Tamas, Bercic, Rebeka Lucijana, Felicijan, Mateja, Luczaj, Lukasz
• Format: Article
• Language: English
• Subjects: Alanine; Amino acids; Analysis; Arginine; Asparagine; Biochemistry; Coumaric acid; crop intraspecific diversity; Environmental aspects; Food industry; Food processing; free amino acids; Genotypes; Glutamine; Kaempferol; leaf traits; Leaves; Management; Metabolites; morphological variability; Morus alba; Morus alba L; Mulberry; Multivariate analysis; p-Coumaric acid; Pharmaceutical industry; phenolics; Phenols (Class of compounds); Physiological aspects; Plant biochemistry; Plant morphology; Proteins; Pruning; Quercetin; Quercetin-3-glucoside; Rutin; Sericulture; Serine; Threonine; Trees
• ISSN: 0001-6977; 2083-9480
• DOI: 10.5586/asbp.3614

Over centuries, in many European countries, the white mulberry trees (Morus alba L.) became an integral part of the cultural landscape, bearing witness to past sericulture activities. The distribution records of white mulberry trees in the cultural landscape are incomplete and in general poorly documented. The aim of the presented research was to collect data regarding geographical locations of mulberry trees and to define their morphological and biochemical variability in Goriska region, one of the historical sericulture regions in Slovenia. Principal component analysis of all morphometrical leaf traits allowed us to characterize two separate groups of morphotypes. Recordings of the tree pruning management revealed that annual base cutting is traditionally used in Goriska region. Significant correlations between pruning management and leaf morphology traits showed that frequently pruned trees form larger leaves. Biochemically, mulberry leaves are shown to be rich in proteins containing threonine, arginine, asparagine, serine, and glutamine as the most prominent free amino acids. The main phenolic compounds were identified as caffeoylquinic acid derivatives, quercetin malonyl-hexoside, rutin, kaempferol acetyl-hexoside, quercetin-3-glucoside, and p-coumaric acid derivatives. The difference in concentrations of the investigated metabolites is correlated either with the pruning management or the morphotype. Pruning significantly affected the levels of asparagine, alanine, and serine, which were higher in the annually pruned trees regardless of the morphotype. Furthermore, we were able to confirm a significant effect of pruning on total phenolics as well as on the levels of rutin, quercetin malonyl-hexoside, and quercetin-3-glucoside contents. Multivariate analysis allowed us to determine seven chemotypes with distinctive biochemical traits. Our results are the basis for defining superior high-yielding genotypes with optimum metabolic composition for both silkworm feeding as well as for innovative usage in food processing and pharmaceutical industries. Keywords free amino acids; crop intraspecific diversity; leaf traits; morphological variability; Morus alba L.; phenolics; proteins; sericulture Citation Urbanek Krajnc A, Ugulin T, Pausic A, Rabensteiner J, Bukovac V, Mikulic Petkovsek M, et al. Morphometric and biochemical screening of old mulberry trees (Morus alba L.) in the former sericulture region of Slovenia. Acta Soc Bot Pol. 2019;88(1):3614.