Characteristics and varietal phylogenetics of Peliosanthes teta Andr., Basella alba L. and Gymnema inodorum Decne. collected from some areas in the upper-north of Thailand

Abstract

Local and indigenous vegetables have gained increasing attraction among the towners these days when cultivation of such vegetables is restricted to the rural communities. Apart from this, exploitation of some indigenous plants from their natural habitats is still at large. Attempts have been made in conserving genetic resources of these plants through surveying, collecting, growing and maintaining the plants while sustainable utilization has been publicly campaigned. Being part of this plant genetic resources conservation, this research was organised accordingly. Surveys and collections of three local vegetables, i.e. Nang Laeo (Peliosanthes teta Andr.), Phak Plang (Basella alba L.) and Chiang Da (Gymnema inodorum Decne.), were hence conducted, covering some areas of eight provinces of the Upper-North of the country. Studies on characterizations of the plants were consequently carried out. Surveys and collections of the plants were done in the provinces of Chiang Mai, Chiang Rai, Lampang, Lamphun, Mae Hong Son, Nan, Phayao and Phrae. Accessions of the plants collected were 349 in number, being 72, 172 and 105 of Nang Laeo, Phak. Plang and Chiang Da, respectively. They were gathered from 120 villages of 48 districts. From interviews made to the locals, the plants were grown in the homestead among other vegetables, mainly for household consumption. Surplus was sold in local market, but only in very small quantity. The plant parts used as food was young inflorescences in Nang Laeo, young shoots and young inflorescences in Phak Plang and young shoots in Chiang Da. Growth studies showed that Nang Laeo was herbaceous perennial in nature. It grew all year round, producing inflorescence seasonally around April to May. Phak Plang was an annual, flowered in September while Chiang Da was perennial, bloomed during May to June. Characteristics of the three plant species were evaluated from collected samples grown in cultivation plots. Morphological characterization revealed different types of the plants, Nang Laeo of rhizomatous, Phak Plang of climber and Chiang Da of lianous. Characteristics of the three species were described in details. Evaluation of leaf characters of individual species using UPGMA cluster analysis carried out among collected samples could classified those of Nang Laeo, Phak Plang and Chiang Da into 4, 3 and 3 groups at the coefficient indices of 63%-76%, 55%-70% and 47%-76%, respectively, according to their relatedness. Examination of pollen morphology showed that the pollen of Nang Laeo appeared as ellipsoidal monad. Pollen aperture was monosulcate with the exine of regulate type. Phak Plang’s pollen appeared in cuboidal monad of 6-colpate aperture and reticulated exine while the pollen of Chiang Da was in form of pollinia, waxy and yellow in colour. Anatomical studies of the plants from longitudinal and transverse sections of root, stem, leaf and flower sampled from mature plants clearly expressed that different organs of the plants comprised three tissue systems of dermal, ground and vascular. Samples of the same species obtained similar internal structure of the plant body but differences could be figured from details of the form, shape and density of cells in each tissue system. In individual species specific characters were observed, obviously from patterns of inorganic accumulation in certain cell types appearing in particular areas. Karyotypic studies yielded appropriate technique of root tip tissue preparation for chromosome investigation. The protocol was as follows: root sampling at 10.00 a.m., pre-treating in PDB at 10oC for 6, 8 and 2 hours for Nang Laeo, Phak Plang and Chiang Da, respectively, fixing in Carnoy’s solution for 5 minutes, macerating in 1 N HCl for 5 minutes and staining in carbol fuchsin for 6, 4 and 8 hours, respectively. Chromosome counts showed that the chromosome number of Nang Laeo was 2n = 54, Phak Plang Khao was 2n = 38, Phak Plang Daeng was 2n = 44 and Chiang Da was 2n = 22. Karyotype formulae evaluating from the size and configurations of the chromosomes were different, according to plant species and representative samples. Isozyme patterning studied from polyacrylamide gel electrophoresis using the enzyme systems of acid phosphatase, esterase, glucose dehydrogenase, glutamate oxaloacetate transminase, leucine aminopeptidase, malate dehydrogenase, peroxidase and shikimate dehydrogenase expressed different band patternings enabled classification of the samples from their relatedness evaluated by using NTSYSpc programme version 2.21i. This research provides valuable information for conservation of Nang Laeo, Phak Plang and Chiang Da. Practical techniques and evaluations gathered from the studies can be used as the prototypes for further studies.