Edaphic relations of Cirsium cassium Davis & Parris ( Asteraceae ) , a local endemic from Hatay ( Turkey )

This study was carried out during 2012-2015. Our aim was to determine the soil-plant relationships of Cirsium cassium distributed in Hatay province of Turkey. This local endemic species was collected from three different localities in Hatay. The analysis of soil samples revealed that this endemic plant prefers clayey-loam, nonsaline, slightly alkaline soils with a high lime content. The nitrogen and potassium contents are of sufficient level but the soils are rich in phosphorus. Analysis of root, stem and leaf shows that nitrogen and phosphorus are below normal values in all plant organs; sodium is above the normal value in all plant parts. The potassium is below normal values in root and stem, but above normal values in leaf.


Introduction
Phytogeographically Turkiye occupies an important position in the world from the viewpoint of plant genetic resources and genetic diversity (Ozturk et al., 2016).The report published by WWF for Turkiye includes 122 important plant areas but, the nature association has identified 305 key biodiversity areas on the basis of endemism in the country (Eken et al., 2016;Ozturk et al., 2016).The fundamentals of species conservation are determination of distribution and ecology of the species (Çınar and Tuğ, 2015).The effective factors of the distribution areas are the macro and micro climatic features, habitats and soil characteristics of the plant niches together with the interactions with other species (Çınar and Tuğ, 2015;Ozturk et al., 2016).
Many endemic taxa show a restricted distribution, which is one of the main subjects of several ecological and phylogenetical studies (Çınar and Tuğ, 2015;Ozturk et al., 2016).The main reasons for this are listed as low ecological tolerance, specialized habitat requirements, low dispersal ability, and/or low reproductive capacity.Many plant endemics in Turkiye have only one distribution area, their systematics is well-known but information on their ecology, population structure, and reproductive biology is not enough.It is very important that ecology and genetics of target species must be fully evaluated if we want their proper and successful conservation (Çınar and Tuğ, 2015;Oztürk et al., 2016).

Materials and Method
Plant (root, stem and leaf) samples of Cirsium cassium Davis & Parris (Asteraceae) and soil samples from their growth habitats were collected from three different localities in Hatay (especially from the roads extending between Samandağ and Yayladağ Districts).The root, stem, and leaf samples were oven-dried at 80 °C for 48 hours, milled in micro hammer cutter and passed through 1.5-mm sieve.0.5 g of samples was weighed and transferred into Teflon vessel and 8 ml of 65% HNO 3 was added.The samples were mineralized in microwave oven at 145 o C for 5 min., at 165 o C for 5 min.and at 175 o C for 20 min.After cooling, samples were filtered using Whatman filters.The volume was made up to 50 ml with ultrapure water.Standard solutions were prepared by using multi element stock solutions-1000 ppm (Merck).The potassium and sodium measurements were conducted by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES).Nitrogen and phosphorus were determined by the methods outlined in detail in Öztürk et al. (1997).500 g of soil samples were taken from a depth of 30 cm from all localities.pH was determined by Hanna 211 pH meter; total soluble salt (TSS) and conductivity values were measured by Hanna E.C. 211 conductivity meter; soil texture was determined with Bouyoucos Hydrometer; CaCO 3 was measured by Scheibler calcimeter; modified Kjeldahl method was used for total nitrogen analysis; phosphorus was determined by using Olsen method; all measurements were taken according to the methods outlined in detail in Öztürk et al. (1997), potassium and sodium concentrations were measured by using ICP-AES (Altay et al., 2016a).

Results
The soil analysis of C. cassium reveals that it generally prefers clayey soils with a soil pH of 7.80-7.92and EC 242 to 395 (μS/cm).The values for calcium carbonate lie between 11 to 19 (%), nitrogen between 0.010 to 0.282 (%), phosphorus between 15.950 to 16.925 (mg kg −1 ), sodium 34 to 41 (mg kg −1 ) and potassium 174.50 to 520.00 (mg kg −1 ).The results of analysis of C. cassium of roots, stems and leaves collected during flowering season show that on dry weight basis the nitrogen values range between 0.078-0.178(%), phosphorus between 0-563 (mg kg -1 ), sodium between 250-370 (mg kg −1 ) and potassium between 250-370 (mg kg −1 ) in roots.In the stems the nitrogen values range between 0.044-0.060(%), phosphorus between 0-100.5 (mg kg −1 ), sodium between 390-555 (mg kg −1 ) and potassium between 340-555 (mg kg −1 ).In the leaves the nitrogen values range between 0.092-0.153(%), phosphorus between 0-90 (mg kg −1 ), sodium between 105-615 (mg kg −1 ), and potassium betwen 635-10,000 (mg kg −1 ).The soil analysis data shows that this endemic taxon prefers clayey-loamy, nonsaline, slightly alkaline soils with high lime content, nitrogen and potassium are at sufficient level, and phosphorus is rich in the soil.Epstein (1999) has reported that N, P, K and Na values follow as: 1.5%, 2,000 (mg/kg), 10,000 (mg/kg) and 10 (mg/kg) respectively in plants.According to our analysis results of root, stem and leaf parts nitrogen and phosphorus are below normal values in all plant organs; sodium is above the normal value in all plant parts.In addition, potassium values are below normal values in root and stem, but above normal values in leaf.

Discussions
Endemics and threatened plants are an important part of plant diversity, these are in need of immediate intervention in order to ascertain their long-term survival (Jalli et al., 2015).The strategies for plant conservation include in situ approaches such as, establishing protected areas, national parks, biosphere reserves and gene sanctuaries; whereas ex situ approaches include seed conservation genebanks, field genebanks and in vitro conservation.An application of different conservation approaches will prove helpful in saving plant taxa in danger.It will also widen our knowledge regarding these species.All these will pave way for their sustainable use beneficial for humans (Jalli et al., 2015).
Circium cassium, being a narrow endemic, must be given priority, and monitored carefully in order to preserve the genetic diversity of this species since endemic species are much more vulnerable to extinction at much higher rates than other species.In addition, ecological studies about such endangered endemic taxa should be supported with comprehensive physiological and molecular studies to promote the understanding about the narrow endemics (Altay et al., 2013;2016a,b;Eroğlu et al., 2014).

Table 1 .
Physical and chemical analysis of the soil samples from the study sites

Table 2 .
Chemical analysis of the plant parts (root, stem and leaves) of C. cassium