ABSTRACT
Two typical broadleaved trees (i.e., Fraxinus rhynchophylla and Acer mono) with wind-dispersed seeds in Northeast China were selected in this study. A method of 15N isotope labeling was used to explore the accumulation responses of seeds and seedlings to 15N-urea soaking concentration (0, 0.05, 0.1 and 0.2 g·L-1), soaking time (4, 8 and 12 days) and leaf stage (2, 4, 6, and 8 leaves). The results showed that 15N-urea soaking concentration and soaking time had significantly positive effects on δ15N values of seeds, i.e., higher 15N-urea concentration and longer period of soaking (0.2 g·L-1+12 d) were contributed to more 15N accumulation of seeds. The maximum multiples of 15N accumulation in F. rhynchophylla seeds and A. mono seeds were observed in 0.1 g·L-1+ (4 d, 8 d) and 0.05 g·L-1+ (4 d, 8 d), respectively. The loss rate of δ15N values decreased markedly from 2 leaves to 6 leaves and then kept relatively stable with the increasing seedling height, and the total δ15N values of seedlings started to decline at the stage of 8 leaves. These results suggested that seedlings with 6 leaves were more suitable for tracking seedling source. The δ15N values in leaves of seedlings were significantly positively correlated with 15N-urea concentration level, soaking time and δ15N values of seeds. Overall, the accumulation of 15N-urea could be found in seeds and seedlings of F. rhynchophylla and A. mono. The combination of 15N-urea concentration (0.1 g·L-1), soaking time (8 d) and leaf stage (6 leaves) was the most suitable for tracking the seeds and seedlings of these two broadleaved trees.
Subject(s)
Acer/metabolism , Fraxinus/metabolism , Nitrogen Isotopes/metabolism , Seedlings/metabolism , Seeds/metabolism , China , Plant Leaves , TreesABSTRACT
OBJECTIVE: To investigate allelic and haplotypic polymorphisms of human leukocyte antigen(HLA) genes at A, B and DRB1 loci in Yantai and Weihai Han population and analyze the genetic relationship between Yantai, Weihai Han population and other populations. METHODS: A total of 4062 unrelated Han ethnic individual from Yantai and Weihai regions were genotyped by polymerase chain reaction-sequence specific olignucleotide probe(PCR-SSOP) for HLA-A, B and DRB1 loci. Allelic and haplotypic frequencies were estimated by maximum likelihood estimation method using Arlequin 3.5 software. Genetic distances were computed, and phylogenetic tree was constructed using Mega5.0 software. RESULTS: Respectively 18, 33 and 13 alleles were observed at HLA-A, B and DRB1 loci. The most frequent alleles were HLA-A*02(0.2935), HLA-B*15(0.1485) and HLA-DRB1*15(0.1621). And the most common three loci haplotype was A*30-B*13-DRB1*07(0.0649). A*33-B*58, A*66-DRB1*13 and B*08-DRB1*03 showed the strongest linkage disequilibrium. Yantai and Weihai Han population has the shortest genetic distance with Jilin Han population (0.0034). CONCLUSION: The HLA-A, B and DRB1 loci are highly polymorphic in Han population from Yantai and Weihai, and this population has closest relationship with Han population from Jilin province.