Morphological and chemical characterization of a collection of mountain clover natural populations

Abstract

With climate change evident, the possibility opens up of introducing into production a species that, although not characterized by high yield, nevertheless offers some other benefits for both the environment and man. One of these species is mountain clover (Trifolium montanum L.), a species widespread around European in the past, but due to agricultural activities its habitat has become fragmented and areas of mountain clover impaired. In the present study, the collection of nine natural populations of mountain clover originating from different parts of the hilly-mountainous areas of Serbia was tested in field conditions. We analysed different morphological traits (green plant biomass, stem length, internode number, number of lateral branches, leaf length and leaf width), dry matter quality traits (content of crude proteins, crude fibre and crude fat) as well as secondary metabolites (total phenolic content, flavonoid contents and antioxidative activity). We collected morphological data and plant samples during 2011 and 2012. We performed descriptive statistics to provide basic information about variables in the dataset, then calculated Shannon-Weaver diversity index (H’) and performed two-way ANOVA and principal component analyses (PCA). Analysing the broad range of data collected during two years, we found considerable morphological and chemical diversity amongst the collection of mountain clovers from central Serbia. Mean coefficient of variation (CV) in the morphological dataset ranged from 18% (stem length) to 57.6% (plant biomass) in 2011 and from 16.5% (leaf length) to 70.6% (stem number) in 2012. Dry matter (DM) parameters displayed the lowest CV, ranging from 6.1% (crude proteins) to 14.8% (crude fat), indicating that these parameters were less discriminative within the study collection. Over all populations, average crude protein content was 19.5%, and average crude fibre content was 27.3%. Total phenolic contents (expressed as gallic acid equivalent, GAE) ranged from 49.8 to 89.7 mg GAE g-1 DM, and flavonoid contents (expressed as rutin, Ru, equivalent) ranged from 66.8 to 142 mg Ru g-1 DM. Average antioxidative activity expressed in terms of IC50 values ranged from 177 to 426 mg ml-1 of methanol extract.