Platostoma palustre is an annual herb and an important medicinal and edible plant in southern China. Plastic-film mulching is an effective agronomic practice in the cultivation system of P. palustre, of which black-film mulching is the most common. However, fewer researches have been focused on the use of other colors of plastic films in P. palustre cultivation. In this study, different colors (white, black, red, and green) of plastic film were adopted, and the effects of different colors of plastic film mulching on the soil temperature, yield, and metabolites of P. palustre were investigated. The results showed that the fresh weight of a single plant of the green film treatment was significantly higher than that of the white film treatment (n = top 28). Based on the results of three temperature measurements, the soil temperature was almost the highest in the red film treatment and lowest in the white film treatment. The metabolomic analysis revealed that a total of 103 differential metabolites were identified. Among these, the gluconic acid, deoxyribose, and N-Acetylmannosamine in the red film treatment presented the highest abundance compared with the other treatments, meanwhile, the abundances of the five monosaccharides in the red film treatment were significantly higher than those of the green film treatment. Moreover, the sucrose, trehalose, and D-(+)-trehalose in the green film treatment exhibited the highest abundance, and the abundances of eight different amino acids in the red film treatment were almost the lowest while those in the black film treatment were almost the highest. Further analysis of the membership function values indicated that the black and red film treatments might be more suitable for the cultivation and quality production of P. palustre in comparison with the other two treatments. This study will provide a theoretical basis for improving the efficient cultivation technology of P. palustre and forming a theoretical system of P. palustre film mulching cultivation.

Introduction: Ilex asprella is a common Chinese herb widely distributed in South China with high medicinal value, and its genetic diversity assessment is a prerequisite for the utilization of germplasm resources.Methods: Based on the published genome of I. asprella, this study conducted genome-wide SSR identification and development and performed genetic diversity analysis on 25 germplasm accessions.Results and discussion: The results showed that a total of 137,443 SSR loci were detected across the whole genome of I. asprella. Six types of SSRs were obtained, and the dinucleotide and trinucleotide repeats were dominant, with dinucleotide repeat motifs accounting for 84.20% of the total markers and trinucleotide repeat motifs accounting for 12.22%. A total of 15 highly polymorphic primers were ultimately selected, including 13 dinucleotide primers and 2 trinucleotide primers. The allele distribution of SSR loci in the genome of Ilex asprella was uneven, and the heterozygosity of different loci varied; the fixation index (F) were all greater than 0, indicating that there was an excess of pure heterozygotes in this population; the genetic differentiation coefficient (Fst) was 0.192, and there existed a large amount of genetic differentiation; the mean value of gene flow (Nm) between different loci was 1.175, and there existed a certain degree of gene exchange in the population; the molecular analysis of variance (AMOVA) indicated that the variation of individuals was the main source of total variation. Genetic analysis revealed that the 25 samples can be divided into three populations. pop2 had the highest genetic diversity, followed by pop3, and pop1 had the lowest genetic diversity, suggesting that there were differences in the level of genetic diversity among the populations. Overall, we found that there was a large genetic differentiation in the Ilex asprella population, a high level of genetic diversity, gene exchange between different populations, and high inter-population gene mobility, which was of guiding significance for the subsequent selection and breeding of new varieties of Ilex asprella.