Soil organic matter and water content affect the community characteristics of arbuscular mycorrhizal fungi in Helan mountain, an arid desert grassland area in China.

Introduction: Arbuscular mycorrhizal fungi (AMF) are vital in terrestrial ecosystems. However, the community structure characteristics and influencing factors of AMF in the forest ecosystems of arid desert grassland areas require further investigation. Methods: Therefore, we employed high-throughput sequencing technology to analyze the soil AMF community characteristics at different elevations in the Helan mountains. Results: The results revealed that significant differences (P < 0.05) were observed in the soil physicochemical properties among different elevations, and these properties exhibited distinct trends with increasing elevation. Through high-throughput sequencing, we identified 986 operational taxonomic units (OTUs) belonging to 1 phylum, 4 classes, 6 orders, 12 families, 14 genera, and 114 species. The dominant genus was Glomus. Furthermore, significant differences (P < 0.05) were observed in the α-diversity of the soil AMF community across different elevations. Person correlation analysis, redundancy analysis (RDA), and Monte Carlo tests demonstrated significant correlations between the diversity and abundance of AMF communities with soil organic matter (OM) (P < 0.01) and soil water content (WC) (P < 0.05). Discussion: This study provides insights into the structural characteristics of soil AMF communities at various altitudes on the eastern slope of Helan mountain and their relationships with soil physicochemical properties. The findings contribute to our understanding of the distribution pattern of soil AMF and its associations with environmental factors in the Helan mountains, as well as the stability of forest ecosystems in arid desert grassland areas.

Dam inundation reduces ecosystem multifunctionality following riparian afforestation in the Three Gorges Reservoir Region.

Afforestation is an acknowledged method for rehabilitating deteriorated riparian ecosystems, presenting multiple functions to alleviate the repercussions of river damming and climate change. However, how ecosystem multifunctionality (EMF) responds to inundation in riparian afforestation ecosystems remains relatively unexplored. Thus, this article aimed to disclose how EMF alters with varying inundation intensities and to elucidate the key drivers of this variation based on riparian reforestation experiments in the Three Gorges Reservoir Region in China. Our EMF analysis encompassed wood production, carbon storage, nutrient cycling, decomposition, and water regulation under different inundation intensities. We examined their correlation with soil properties and microbial diversity. The results indicated a substantial reduction in EMF with heightened inundation intensity, which was primarily due to the decline in most individual functions. Notably, soil bacterial diversity (23.02%), soil properties such as oxidation-reduction potential (ORP, 11.75%), and temperature (5.85%) emerged as pivotal variables elucidating EMF changes under varying inundation intensities. Soil bacterial diversity and ORP declined as inundation intensified but were positively associated with EMF. In contrast, soil temperature rose with increased inundation intensity and exhibited a negative correlation with EMF. Further insights gleaned from structural equation modeling revealed that inundation reduced EMF directly and indirectly by reducing soil ORP and bacterial diversity and increasing soil temperature. This work underscores the adverse effects of dam inundation on riparian EMF and the crucial role soil characteristics and microbial diversity play in mediating EMF in response to inundation. These insights are pivotal for the conservation of biodiversity and functioning following afforestation in dam-induced riparian habitats.

Diversity characteristics of arbuscular mycorrhizal fungi communities in the soil along successional altitudes of Helan Mountain, arid, and semi-arid regions of China.

Introduction: Arbuscular mycorrhizal fungi (AMF) perform a vital role in terrestrial ecosystems. Methods: To investigate the diversity of AMF communities on the western slope of Helan Mountain at different altitudes and their influence factors, high-throughput sequencing was used to study the structure and diversity of soil AMF communities under different environments and their interrelationships between AMF and environmental factors. Results: The results revealed that there were significant differences (p < 0.05) in the physical and chemical properties of the soil along the different altitudes. A total of 1,145 OTUs were obtained by high-throughput sequencing, belonging to 1 phylum, 4 class, 6 orders, 13 families, 18 genera and 135 species, with the dominant genus being Glomus, which accounted for 75.27% of the relative abundance of the community. Soil AMF community structure was shown to be variable at the generic level according to NMDS analysis. Correlation analysis showed that soil pH, water content (WC), organic matter (OM), available K, available P and N were significantly correlated with AMF community diversity and species abundance (p < 0.05, p < 0.01). Based on redundancy analysis (RDA) and Monte Carlo test results, soil pH, WC and OM had highly significant effects (p < 0.01) on AMF community diversity and species abundance. Discussion: This study investigates the relationship between AMF community structure and diversity and soil physicochemical properties at different elevations on the western slope of Helan Mountain, which is of great significance to the study of the Helan Mountain ecosystem.

The Effects of American Sign Language on English Reading Proficiency.

The authors examine the effects of American Sign Language (ASL) on English reading achievement and English reading comprehension. A systematic review of relevant primary research and research-integrated journal articles was conducted. Based on interpretations of a few salient articles and other sources (e.g., books) selected in a professional review, background on the ASL-English situation is provided. The authors discuss whether the findings reflect a pattern or suggest instructional implications for improving English reading comprehension. Also discussed is whether the findings are confounded by a lack of desirable research characteristics associated with sample sociodemography, teacher-student interactions, or school environment. The article concludes with recommendations for further research to examine the merits of ASL-English approaches or bilingual programs, focusing on improvement of the English reading skills of d/Deaf and hard of hearing children and adolescents.

Caspase 3-like protease is involved in ethylene-induced programmed cell death during aerenchyma formation in Helianthus annuus stem.

Previous research has reported that hypoxic conditions and ethylene treatments greatly trigger programmed cell death (PCD) occurrence and induce the formation of aerenchyma to adapt stress environment in Helianthus annuus stem. Caspase 3-like protease (CLP) as regulatory signals, also be involved in the process of PCD to adapt the low oxygen environment. However, the relationships between ethylene and CLP have seldom been reported. Herein, To understand the regulatory role of ethylene and CLP signaling molecules in aerenchyma formation, we investigated the effects of exogenous ethephon (ET), ethylene perception inhibitor 1-methylcyclopropene (1-MCP), and the treatment of 1-MCP + ET on morphological, physiological characteristics and aerenchyma formation in H. annuus stem. The results showed that lysigenous aerenchyma formation in H. annuus stem is induced by ET, and immunohistochemistry assay indicate CLP activity is raised at the formation stage of aerenchyma formation, and decreased at the expanding phase of aerenchyma formation. Western blotting illustrate the expression of CLP is also increased within 8 h after ethylene signaling inducing aerenchyma formation, and the activities of CLP are higher in ET treated seedlings than the control and 1-MCP treated seedlings. The same phenomenon was also observed by caspase-3 activity assay. These results revealed there is a causal and interdependent relationship between ET and CLP signaling during the process of aerenchyma formation, which regulating PCD initiation in H. annuus stem.

Programmed cell death associated with the formation of schizo-lysigenous aerenchyma in Nelumbo nucifera root.

Nelumbo nucifera (N. nucifera) is an important aquatic economic crop with high edible, medicinal, ornamental, and ecological restoration values. Aerenchyma formation in N. nucifera root is an adaptive trait to the aquatic environment in long-term evolution. In this study, light microscopy, electron microscopy, and molecular biology techniques were used to study the process of the aerenchyma development and cytological events in N. nucifera root and the dynamic changes of aerenchyma formation under the treatment of exogenous 21% oxygen, ethylene (ET), and ET synthesis i + nhibitor 1-methylcyclopropene (1-MCP). The results showed that programmed cell death (PCD) occurred during the aerenchyma formation in N. nucifera root. Plasmalemma invagination and vacuole membrane rupture appeared in the formation stage, followed by nuclear deformation, chromatin condensation and marginalization, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) detection was positive at this time. In the expansion stage of the aerenchyma development, cytoplasmic degradation and many vesicles appeared in the cytoplasm, and organelles began to degrade. Then the plasma membrane began to degrade, and the degradation of the cell wall was the last PCD step. After 21% oxygen was continuously filled in the rhizosphere environment of N. nucifera roots, the area of aerenchyma in N. nucifera roots was smaller than that in the control group. Moreover, ET induced the earlier occurrence of aerenchyma in N. nucifera root, but also, the area of aerenchyma became larger than that of the control. On the contrary, 1-MCP inhibited the occurrence of aerenchyma to some extent. Therefore, the formation of aerenchyma in N. nucifera root resulted from PCD, and its formation mode was schizo-lysigenous. A hypoxic environment could induce aerenchyma formation in plants. ET signal was involved in aerenchyma formation in N. nucifera root and had a positive regulatory effect. This study provides relevant data on the formation mechanism of plant aerenchyma and the cytological basis for exploring the regulation mechanism of plant aerenchyma formation.