Belowground Bud Bank Is Insensitive to Short-Term Nutrient Addition in the Meadow Steppe of Inner Mongolia

Human activities and industrialization have significantly increased soil nutrients,such as nitrogen(N)and phos-phorus(P),profoundly impacting the composition and structure of plant community,as well as the ecosystem functions,especially in nutrient-limited ecosystems.However,as the key propagule pool of perennial grasslands,how belowground bud bank and its relationship with aboveground vegetation respond to short-term changes in soil nutrients was still unclear.In this study,we conducted a short-term(2021–2022)soil fertilization experiment with N addition(10 g N m^(-2) yr^(-1))and P addition(5 g N m^(-2) yr^(-1))in the meadow steppe of Inner Mongolia,China,to explore the responses of belowground bud bank,aboveground shoot population and their relationships(represented by the ratio of bud to shoot density-meristem limitation index(MLI))for the whole community and three plant functional groups(perennial rhizomatous grasses-PR,perennial bunchgrasses-PB,and perennial forbs-PF)to nutrient addition.The short-term nutrient addition had no significant influences on belowground bud density,aboveground shoot density,and MLI of the whole plant community.Plant functional groups showed different responses to soil fertilization.Specifically,N addition significantly increased the bud density and shoot density of PR,especially in combination with P addition.N addition reduced the shoot density of PF but had no influence on its bud density and MLI.Nutrient addition had significant effects on the three indicators of PB.Our study indicates that the belowground bud bank and its relationship with aboveground vegetation in temperate meadow steppe are insensitive to short-term soil fertilization,but plant functional groups exhibit specific responses in terms of population regeneration,which implies that plant community composition and ecosystem functions will be changed under the ongoing global change.

Soil Moisture Rather than Soil Nutrient Regulates the Belowground Bud Bank of Rhizomatous Species Psammochloa villosa in Arid Sand Dunes

In arid and semi-arid sand dune ecosystems,belowground bud bank plays an important role in population regeneration and vegetation restoration.However,the responses of belowground bud bank size and composition to sand burial and its induced changes in soil environmental factors have been rarely studied.In arid sand dunes of Northwestern China,we investigated belowground bud bank size and composition of the typical rhizomatous psammophyte Psammochloa villosa as well as three key soil environmental factors(soil moisture,total carbon and total nitrogen)under different depths of sand burial.Total buds and rhizome buds increased significantly with increasing burial depth,whereas tiller buds first increased and then decreased,with a peak value at the depth of 20-30 cm.Soil moisture increased significantly with sand burial depth,and was positively correlated with the number of all buds and rhizome buds.Soil total carbon concentration first increased and then decreased with sand burial depth,and total nitrogen concentration was significantly lower under deep sand burial than those at shallow depths,and only the number of tiller buds was positively correlated with soil total nitrogen concentration.These results indicate that soil moisture rather than soil nutrient might regulate the belowground bud bank of P.villosa,and that clonal psammophytes could regulate their belowground bud bank in response to sand burial and the most important environmental stress(i.e.,soil moisture).These responses,as the key adaptive strategy,may ensure clonal plant population regeneration and vegetation restoration in arid sand dunes.

The intricacies of neurotrophic factor therapy for retinal ganglion cell rescue in glaucoma: a case for gene therapy

Regeneration of damaged retinal ganglion cells（RGC） and their axons is an important aspect of reversing vision loss in glaucoma patients. While current therapies can effectively lower intraocular pressure, they do not provide extrinsic support to RGCs to actively aid in their protection and regeneration. The unmet need could be addressed by neurotrophic factor gene therapy, where plasmid DNA, encoding neurotrophic factors, is delivered to retinal cells to maintain sufficient levels of neurotrophins in the retina. In this review, we aim to describe the intricacies in the design of the therapy including： the choice of neurotrophic factor, the site and route of administration and target cell populations for gene delivery. Furthermore, we also discuss the challenges currently being faced in RGC-related therapy development with special considerations to the existence of multiple RGC subtypes and the lack of efficient and representative in vitro models for rapid and reliable screening in the drug development process.