The Difference Of Mn-accumulative Traits And Genetic Relationship Among Four Celosia L.Species

Through its constant reports on the"cadmium-rice","arsenic-toxic"and"blood lead",the issue of heavy metal polluted soil caused widespread concern.A mass of production and consumption of manganese will undoubtedly increase the risk of soil manganese pollution.Mn is one of the essential trace elements for plant growth,but interestingly excess manganese will inhibited plant growth.C.argentea L.,a typical Mn hyperaccumulator,has been found after a series of field investigations.Four Celosia L.Species?include C.argentea L.,C.cristata L.,C.taitoensis Hay.,and Celosia cristata var.plumosa?was selected to investigate the difference of tolerance and enrichment under high level of Mn using pot experiments.To explore the genetic relationship of Mn hyperaccumulators.The results showed that the manganese tolerance of C.argentea L.is better than the others.Under the Mn stress,C.cristata L.and C.taitoensis Hay.were poisoned in different degree.Especially all of C.taitoensis Hay.plants were dead at 500 mg·kg^-11 Mn treatment.In order to estimate the difference of Photosynthesis among 4 Celosia L.plants under the Mn stress,chlorophyll fluorescence parameters in 30 d and 60 d were measured.It was found that the maximum fluorescence?F_m?,maximum quantum yield?F_v/F_m?,photo chemical quenching?qP?and electron transport rate?ETR?of C.cristata L.and C.taitoensis Hay.gradually were decreased and the minimal fluorescence?F₀?were increased with the concentration in the media increasing.And the non-photo chemical quenching?NPQ?of C.cristata L.and C.taitoensis Hay.at 30 day were increased,however the NPQ at 60 day were decreased.The result of chlorophyll fluorescence parameters indicated that Mn stress inhibited the electronic transfer process in the C.cristata L.and C.taitoensis Hay..The F_0,F_m,F_v/F_m value of C.cristata L.and C.cristata var.plumosa were decreased by Mn stress.In addition,the NPQ protection mechanism of C.cristata L.still works with Mn stress time increasesd.In the same green houses and the same under Mn stress respectively seeding the seed of4 Celosia L.plants for germination experiment.The results show that the seed germination rate,germination potential,and germination index of 4 Celosia L.plants decreased with the increase of Mn supply rate.However,Mn stress had relatively little effects on C.argentea L.seed.The results showed that C.argentea L.leaf biomass increased at 500 mg·kg^-11 Mn,although visible symptoms in foliage were observed.At 500 mg·kg^-11 Mn,Mn content reached to a maximum value of 25,363.28 mg·kg^-11 in the leaf,and the Mn bioaccumulation coefficient factor was 30.05,and the Mn translocation factor was 1.31-5.42.This species has not only a high tolerance to Mn,but also a hyper-accumulation capacity for Mn²⁺.But it results showed C.cristata L.,C.taitoensis Hay.,and C.cristata var.plumosa lack of capacity of Mn hyper-accumulation.This study was aimed to analyzed the genetic diversity and relationship famong 4Celosia L.species with sequence-related amplified polymorphism?SRAP?markers.The 9SRAP primer combinations generated a total of 317 clear and stable bands,of which317?100%?were polymorphic,ranging in size from 60 to 1500 bp.And the value of genetic diversity parameters were Na=2.0000,Ne=1.4440±0.2589,H=0.2868±0.1159,I=0.4527±0.1383.A dendrogram was constructed based on the SRAP data using UPGMA cluster method.The result illustrated these materials had fairly large genetic difference.