Characterization of the physiological parameters, effective components, and transcriptional profiles of Polygonum multiflorum Thunb. Under pH stress.

Polygonum multiflorum Thunb. is a traditional Chinese medicine with extensive distribution and robust adaptability, but comprehensive research on its acid and alkali resistance is presently lacking. This study aimed to analyze the effects of 5 months of continuous pH stress on the physiological and photosynthetic parameters of P. multiflorum, and the content of effective components. Results revealed that pH stress significantly influenced the normal growth, physiological functions, and photosynthetic indicators of P. multiflorum. At soil pH 4.5, the tubers of P. multiflorum exhibited the highest levels of 2,3,5,4'-tetrahydroxy stilbene-2-O-ß-d-glucoside (THSG) and total anthraquinones at 5.41% and 0.38%, respectively. However, increased soil pH significantly reduced the content of THSG and total anthraquinones. Reference-free transcriptome analysis was further conducted on P. multiflorum treated at pH 4.5 and 9.5, generating a total of 47,305 unigenes with an N50 of 2118 bp, of which 31,058 (65.65%) were annotated. Additionally, 2472 differentially expressed genes (DEGs) were identified. Among them, 17 DEGs associated with the biosynthesis of THSG and anthraquinones were screened. A comprehensive analysis of differential gene expression and effective component content demonstrated a significant positive correlation between the content of effective components and the 14 DEGs' expression but a negative correlation with soil pH. This study highlighted the influence of varying soil pH values on the effective component content of P. multiflorum. Specific acidic conditions proved beneficial for the synthesis and accumulation of THSG and total anthraquinones in P. multiflorum, thereby enhancing the quality of the medicinal material.

Different responses to joint exposure to cadmium and zinc depends on the sex in Populus cathayana.

The alarming increase in soil contamination by heavy metals, such as cadmium and zinc demands immediate attention. The dioecious tree Populus cathayana, a phytoremediation plant, plays an important role in rehabilitating heavy metal contaminated areas. In this study, male and female P. cathayana plants were treated with Cd (20 mg kg-1) and different levels of Zn (25, 50, or 100 mg kg-1) to study their physiological responses. The results showed that Cd exposure alone caused stress by inhibiting the growth of both male and female plants. In both males and females, photosynthesis and antioxidant enzymes activities decreased substantially under Cd stress alone. Cd was largely located in the roots, but Zn was present in the shoots of both sexes. Zn supplementation considerably increased the photosynthetic rate from 14.62 % to 60.45 % and also enhanced the antioxidant enzymes activities from 24.11 % to 86.21 %. Zn treatment decreased the translocation ability of Cd compared to the Cd-only treatment, alleviating Cd toxicity. In addition, when sufficient Zn was made available, males showed a high degree of Cd accumulation, low root-to-shoot translocation, elevated antioxidant defense abilities, and an increased photosynthetic rate, while females were less responsive to Cd stress than males. Thus, combined exposure to Cd and Zn caused differential responses in plant growth and physiological processes between males and females P. cathayana. Male plants exhibit better Cd tolerance and accumulation capacity under optimum Zn supplementation. This study increases the fundamental knowledge regarding P. cathayana plants, which can be applied to enhance their remediation capacity in Cd-contaminated soils.

[Principal component and cluster analysis of trace elements in Chinese herb Salvia miltiorrhiza and its relative species].

The contents of trace elements, including copper, zinc, iron, magnesium, calcium, chromium, lead, molybdenum, manganese, and cadmium in Chinese traditional herb S. miltiorrhiza and its relative species such as S. miltiorrhiza f. alba, S. evansiana, S. yunnanensis, S. przewarlskii, S. cavaleriei, S. cavaleriei var. simplicifolia, S. roborowskii, S. omeiana, S. tricuspis, S. brevilabra and S. cynica were determined by atomic absorption spectroscopy. The principal components analysis of SPSS was applied to the study of characteristic elements in S. miltiorrhiza and its relative species. Three principal components which accounted for 79.3% of total variance were extracted from the original data. The first factor accounted for 49.6% of the total variance, which means that iron, manganese, copper, zinc, cadmium and lead are the characteristic elements in S. miltiorrhiza and its relative species. The results of cluster analysis show that the samples could cluster reasonably into two groups. The samples of S. miltiorrhiza from different regions were classified into one group except S. miltiorrhiza from Zhejiang and S. miltiorrhiza f. alba. The other Salvia species were classified into another group except S. cavaleriei. The S. miltiorrhiza and other Salvia species can be distinguished by this method, whose accuracy of classification is 90%. The cluster analysis based on the contents of trace element in S. miltiorrhiza and its relative species provided a quick, accurate and simple method for authentication of herb Salvia miltiorrhiza.