Investigation On Poisonous Plants And Nutritional Ingredient Analysis And Toxicological Evaluation Of Poisonous Plants In Grassland Of Changdu In Tibet

The Qinghai-Tibet Plateau is an important barrier to the ecosystem.Changdu,which is located in its hinterland,also plays an important role.In this study,the detailed basic data of natural grassland type,toxic plant species,geographical distribution and hazard status in Changdu area were investigated through the practical,and determined the main poisonous plant species that endanger the natural grassland.the nutrient components of the major poisonous plants were analyzed,the LD₅₀was determined by acute toxicity test in mice,and the comprehensively evaluate the nutritional value and toxicity of the main toxic plants.It lays a foundation for the effective prevention and control and rational development and utilization of toxic plants in natural grassland in the region.The results are as follows:1.Investigation on Poisonous Plants in Natural Grassland in Changdu,Tibet:Use actual investigations,combined with literature.The results showed that there were more than 900plants resources in Changdu.The survey results show that there are 150 kinds of poisonous plants in Changdu.Among them,there are 104 kinds of poisonous plants in natural grassland,belonging to 24 families and 54 genera.Among these poisonous weeds,there are 1species ferns,belong to 1 family and 1 genera;there are 3 species gymnosperms,belong to 1family and 1 genera;there are 100 species angiosperm,belong to 22 family and 52genera.Oxytropis ochrocephala,Astragalus strctus,Astragalus confertus,Stellera chamaejasme L.,Pedicularis longiflora,Ligularia sagitta,Pedicularis cephalantha have become natural grassland advantages Species in Changdu,and they seriously endanger the grassland animal husbandry development and ecological security.2.Analysis of nutrient composition of 7 main poisonous plants in Changdu natural grassland:In this chapter,The nutrient contents of the whole grass in the aboveground parts of the 7 kinds of toxic plants in the Changdu natural grassland were determined using the national standard method.The results showed that in the 7 plants,the crude protein content is the highest in Astragalus confertus;the crude fat content is the highest in Stellera chamaejasme L.;the content of crude ash、crude fiber、neutral detergent fiber、and acid washing fiber are the highest in Astragalus strctus.The content of P,Ca,Mg and K in four major minerals from high to low are as follows:Stellera chamaejasme L.、Ligularia sagitta Ca>K>Mg>P;Astragalus strctus、Pedicularis longiflora Ca>K>P>Mg;Astragalus confertus、Pedicularis cephalantha、Oxytropis ochrocephala K>Ca>P>Mg.The content of trace elements from high to low in 7 kinds of plants are all Fe>Mn>Zn>Cu.The contents of Cu,Fe,and Ca are the highest in Astragalus strctus,the contents of Mn and Zn are the highest in Pedicularis longiflora;P content is the highest in Pedicularis cephalantha、Pedicularis longiflora.The amino acid content is 8.03%,11.43%,26.80%,8.36%,4.63%,7.30%,11.97%,respectively.3.Toxicity evaluation of 7 kinds of main toxic plants in Changdu natural grassland:Acute Toxicity Test in Mice:In this chapter,the toxicity of LD₅₀on the aerial parts of the 7 main poisonous plants in Changdu Natural Grassland was determined by gavage in mice.The test results showed that the LD₅₀of Stellera chamaejasme L.was 63.39 g/kg,the 95%confidence limit was 55.94-71.83 g/kg;the LD₅₀of Astragalus strctus was 72.54 g/kg,the 95%confidence limit was 63.84-82.43 g/kg;and the LD₅₀of Astragalus confertus was 100.74g/kg,the 95%confidence limit was 86.88-116.82 g/kg;the LD₅₀of Pedicularis cephalantha was 97.07g/kg,the 95%confidence limit was 86.28-109.22 g/kg;the LD₅₀in Ligularia sagitta was100.95 g/kg,the 95%confidence limit was 88.92-114.60 g/kg;and the LD₅₀of Pedicularis longiflora was 117.25 g/kg,the 95%confidence limit was 109.47-125.57 g/kg;the LD₅₀of Oxytropis ochrocephala was 106.49 g/kg,the 95%confidence limit was 90.68-125.05g/kg.Combined with the clinical symptoms of poisoned mice.The seven kinds of plants were considered to have certain toxicity.The toxicity was ranked as follows:Stellera chamaejasme L.>Astragalusstrctus>Pediculariscephalantha>Astragalusconfertus>Ligularia sagitta>Oxytropis ochrocephala>Pedicularis longiflora.