Establishment Of Regeneration System And Screening Of Salt-tolerant Mutants Of Paspalum Wettsteinii Hack.

Paspalum wettsteinii Hack.is a common turfgrass grass of Paspalum.It is widely used in lawn planting,slope protection and feeding value,but there is no research on its in vitro culture and new breed cultivation.In order to meet the needs of turf market and new varieties with high quality,the regeneration system of Paspalum wettsteinii Hack.was successfully constructed and new salt tolerant plants were initially obtained.In this paper,the seed germination and plant growth of wild-type Paspalum wettsteinii Hack.were carried out respectively to determine the salt tolerance of the grass;Secondly,the seed was used as explant material to successfully construct a complete regeneration system of Paspalum wettsteinii Hack.,and obtain the best medium scheme and technical method in each stage,and provide material and technical support for subsequent research;Callus of Paspalum wettsteinii Hack.was used as material.Materials,through the somaclonal variation,the salt tolerant mutant callus was successfully screened out,and the salt tolerant mutant plants were initially obtained;Finally,the salt tolerance of the mutant plants,and wild type plants and common regenerated plants were evaluated,and the salt tolerance of the salt tolerant mutant plants was significantly higher than that of other plants(P<0.05).The main results are as follows:1.The seed germination rate of Paspalum wettsteinii Hack.increased first and then decreased with the increase of salt concentration.The low concentration of salt ion was beneficial to seed germination and seedling growth.The lethal concentration of seed germination was 305.75 mM by establishing regression equation with seed germination rate and plant survival rate as indicators,respectively.The leaf color score and withered yellow rate of wild Paspalum wettsteinii Hack.plants were negative under different salt concentration Correlation(-0.923**),and there was a very significant difference(P<0.001),at 295.04 mM salt concentration,the plant completely withered.2.The tissue culture system of Paspalum wettsteinii Hack.seed was used explant:Seeds were shaken with 0.8%NaCl(50 ml)for 24 hours,24℃,140 R/min,washed with sterile water for 3-4 times(15 s/time),and finally soaked in 50 ml sterile water for 12 hours;The best medium for callus induction:MS+4.0 mg/L 2,4-D;The best medium for proliferation:MS+4.0 mg/L 2,4-D;The best medium for differentiation:MS+2.0 mg/L 6-BA+0.5 mg/L Na A.the best rooting medium was 1/2MS+2.0mg/l NAA+0.2mg/l 6-BA.The survival rate of the differentiated seedlings was high after 3 days of training.3.Selection of salt tolerant mutants:The critical concentration of salt tolerant proliferation of common callus was 294.00 mM;294 mM was used as the selected salt concentration of the selection medium,and two high-quality salt tolerant mutants were selected from a large number of common callus by using the method of somatic clone mutation.The proportion of selection was 5000:2,and the regenerated plants of salt tolerant mutants were initially obtained.4.Evaluation of salt tolerant mutants:Taking wild type plants and common callus as control,soil culture and water culture were used to identify salt tolerance(294.00 mM)of the mutants respectively.It was found that more than 80%of the mutants were superior to the control group in leaf color,turf value and withered yellow rate(P<0.001),and the mutants were initially obtained.