Plant Biology最新文献

Shrubs are perennial, multi-stemmed woody plants whose adaptation to stress factors allows them to colonise extreme habitats, including high elevations. Accordingly, shrubs are one of the most important growth forms in mountain regions, but their hydraulic properties are poorly understood. We conducted a literature search on the water use strategies of mountain shrubs, focusing on their main hydraulic traits related to water uptake, transport and release, as well as hydraulic limitations in summer and winter. In addition, the leaf cuticular conductance was measured in selected Alpine species. A total of 104 publications were found, mainly from North America, Europe and Asia, and a few from Africa and South America, with snow and steppe habitats strongly underrepresented. The dataset revealed a wide range of specific hydraulic conductivity (k_s; 0.8–25.8 × 10⁻⁴ m²s⁻¹ MPa⁻¹), with highest values in tundra shrubs, and of the water potential at 50% conductivity loss (Ψ₅₀; −11.8 to −0.29 MPa), with lowest values in steppe and temperate dry summer species. Deep-rooted shrubs from arid environments had access to more reliable water sources, while others relied on shallow but nutrient-rich soil water. No clear trend was observed along elevation or precipitation gradients, suggesting a wide range of hydraulic strategies to achieve a balanced water status. Shrub species from arid regions have to withstand low water potentials during the dry season, whereas temperate shrubs experience frost drought and freeze–thaw-induced embolism in winter. The literature review revealed major gaps in the geographic distribution of available studies, and in our knowledge of root characteristics, recovery from embolism, and water storage capacity.

Conventional methods to combat phytopathogens have ecological implications: chemical fertilizers pollute the environment, while bioinoculants are often inconsistent under field conditions. Microbiome-assisted rhizosphere engineering aims to re-structure the rhizosphere microbiome to promote plant growth and/or mitigate stress. This study employs a strategy based on rhizosphere engineering to combat stress caused by Fusarium udum in Cajanus cajan, by generating synthetic microbial communities (SMCs). We used a culture bank of indigenous bacterial strains belonging to the family Bacillaceae, isolated from the rhizosphere of C. cajan with biocontrol activity against Fusarium, and plant growth-promoting (PGP) properties. Various possible combinations of compatible strains were generated, followed by a novel iterative deconvolution technique to establish strains exhibiting enhanced biocontrol traits, when present in a community of other strains. A scoring scheme aided selection of strains for the SMCs, which were tested using in vitro and in planta experiments. Estimating growth attributes and stress markers in plants treated with constituted SMCs helped to select an SMC with maximum biocontrol potential against Fusarium wilt of pigeonpea. A robust SMC was generated with indigenous multi-trait plant growth promoting bacterial strains for sustainable mitigation of Fusarium induced biotic stress with proven efficacy in the host, C. cajan.

Iron (Fe) toxicity is a common agricultural problem that limits rice yield in various regions of Southeast Asia and Africa. Previous studies have proposed physiological mechanisms for tolerance, but the specific genes associated with these mechanisms are largely unknown. In this study, I hypothesized that organic acids play a crucial role in Fe toxicity tolerance in rice and evaluated retrotransposon-insertion mutant lines of citrate transporters under Fe toxicity stress in hydroponics. Fe toxicity-induced leaf bronzing and Fe concentrations were measured. A knock-down line of the xylem-localized citrate transporter, FRDL1, had a significantly lower degree of leaf bronzing symptoms under Fe toxicity when unchelated ferrous iron (Fe²⁺, as FeSO₄), but not chelated ferric iron (as Fe(III)-EDTA), was used as Fe source. The knock-down line of FRDL1 had lower Fe concentrations in leaf blades, while concentrations in stems and roots were unaffected under excess ferrous iron conditions. Knock-down of FRDL1 also reduced foliar Fe concentrations and leaf bronzing symptoms in Ciherang, an indica variety that is highly sensitive to Fe toxicity stress. This study highlights that low xylem citrate concentrations restrict translocation of excess Fe to leaves, suggesting a novel physiological aspect for improved Fe toxicity tolerance in rice. This study also suggests that selection of the Fe source is crucial in Fe toxicity experiments.

Hormones have a dominant role in shaping the destiny of plant reproduction. Recent breakthroughs in our understanding of hormone function during floral development have revealed the pivotal roles of cytokinin, gibberellin and auxin. Cytokinin and gibberellin regulate the size and coordination of floral meristems, while auxin and cytokinin take centre stage in initiating and developing organs. In the past decade, remarkable insights have emerged, revealing the dynamic nature of hormonal impacts throughout reproductive development. It has become evident that a complex network, involving multiple plant hormones, orchestrates the success of plant reproduction. Despite substantial cover of certain aspects of plant reproductive development, there remain significant gaps in our understanding of hormonal regulation and the intricate crosstalk between hormones. In this comprehensive review, we delve into current knowledge and address lingering questions regarding hormone-mediated flower development. By arming ourselves with this knowledge, we pave the way for innovative strategies in effective fruit set management and crop improvement.

More than two centuries since the birth of the botanist Matthias Jacob Schleiden, who first described many duckweed (Lemnaceae) species, interest in these small aquatic monocots is still alive. Lemnaceae have high biomass production capacity and can be used as animal feed and in human nutrition. Efficient transformation protocols and available genome data for several Lemnaceae species make them an ideal model system for research into biosynthesis and physiology of sterols and/or steroids in plants, especially monocots. Here we emphasize how studies using duckweed species can address current problems in plant physiology, with a strong focus on sterol and steroid biology in monocots. Further, we discuss how this knowledge can be translated to solve agricultural and industrial problems.