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Long-term chemical fertilizer input causes soil organic matter losses, structural compaction, and changes in soil water and nutrient availability, which have been subdued in the most of dry farmland in China. The concept of \"more efficiency with less fertilizer input\" has been proposed and is urgently needed in current agriculture. Application of chemical fertilizer combined with organic manure (OM) could be a solution for soil protection and sustainable production of dry-land maize (Zea mays. L). Field research over three consecutive years on the Loess Plateau of China was conducted to evaluate the integrated effects of chemical fertilizer strategies and additional OM input on soil nutrients availability and water use in maize. The results showed that, after harvest, soil bulk density decreased significantly with OM application, concomitant with 11.9, 18.7 and 97.8% increases in topsoil total nitrogen, organic matter, and available phosphorus contents, respectively, compared with those under equal chemical NPK input. Water use in the 1.0-1.5 m soil profile was improved, therefore, the soil conditions were better for maize root growth, leaf area and shoot biomass of individual maize plants increased significantly with OM application. Optimized NPK strategies increased grain yield and water use efficiency by 18.5 and 20.6%, respectively, compared to only chemical NP input. Furthermore, additional OM input promoted yield and water use efficiency by 8.9 and 5.8%, respectively. Addition of OM promotes sustainable soil and maize grain productivity as well as friendly soil environmental management of dry land farming.

Zinc (Zn) deficiency affects 17% of the world’s population, particularly those consuming large cereal grains with low Zn concentration and poor bioavailability. Here, we synthesize data from four field trials along with 139 studies from the literature, to evaluate the impact of management practices and soil properties on improving grain Zn concentration in wheat through applying Zn fertilizers. Soil application of Zn fertilizer improves grain Zn concentration by only 29.1%, below the biofortification target of 40 mg kg −1 required for human nutrition. Foliar Zn application and soil+foliar applications increase grain Zn concentration by 55.2% and 62.3%, respectively, surpassing the 40 mg kg −1 threshold. Factors such as the rate of Zn application, initial grain Zn concentration (prior to Zn application), and timing of Zn spraying are identified as principal factors influencing the response of grain Zn concentration to Zn fertilization. In search of desirable grain Zn concentration in wheat while minimizing potential environmental risks, our study proposes a method for assessing rates of Zn fertilizer application based on the Zn biofortification target, the Zn agronomic biofortification index, and the contribution of principal factors influencing the improvement in grain Zn concentration. Zinc deficiency is a global health issue, particularly in populations consuming wheat with low Zn concentration. This meta-analysis finds that foliar and combined soil+foliar Zn applications significantly increase wheat grain Zn levels, proposing optimized fertilization methods to meet nutritional targets.

Background Understanding root system morphology in bread wheat is critical for identifying root traits to breed cultivars with improved resource uptake and better adaptation to adverse environments. Variability in root morphological traits at early vegetative stages was examined among 184 bread wheat genotypes originating from 37 countries grown in a semi-hydroponic phenotyping system. Results At the onset of tillering (Z2.1, 35 days after transplanting), plants had up to 42 cm in shoot height and 158 cm long in root depth. Phenotypic variation existed for both shoot and root traits, with a maximal 4.3-fold difference in total root length and 5-fold difference in root dry mass among the 184 genotypes. Of the 41 measured traits, 24 root traits and four shoot traits had larger coefficients of variation (CV ≥ 0.25). Strong positive correlations were identified for some key root traits (i.e., root mass, root length, and these parameters at different depths) and shoot traits (i.e., shoot mass and tiller number) ( P  ≤ 0.05). The selected 25 global traits (at whole-plant level) contributed to one of the five principal components (eigenvalues> 1) capturing 83.0% of the total variability across genotypes. Agglomerative hierarchical clustering analysis separated the 184 genotypes into four (at a rescaled distance of 15) or seven (at a rescaled distance of 10) major groups based on the same set of root traits. Strong relationships between performance traits (dry mass) with several functional traits such as specific root length, root length intensity and root tissue density suggest their linkage to plant growth and fitness strategies. Conclusions Large phenotypic variability in root system morphology in wheat genotypes was observed at the tillering stage using established semi-hydroponic phenotyping techniques. Phenotypic differences in and trait correlations among some interesting root traits may be considered for breeding wheat cultivars with efficient water acquisition and better adaptation to abiotic stress.

Background Plants possess mitochondrial genomes that are large and complex compared to animals. Despite their size, plant mitochondrial genomes do not contain significantly more genes than their animal counterparts. Studies into the sequence and structure of plant mitochondrial genomes heavily imply that the main mechanism driving replication of plant mtDNA, and offer valuable insights into plant evolution, energy production, and environmental adaptation. Results This study presents the first comprehensive analysis of Agrostis stolonifera ’s mitochondrial genome, characterized by a branched structure comprising three contiguous chromosomes, totaling 560,800 bp with a GC content of 44.07%. Annotations reveal 33 unique protein-coding genes (PCGs), 19 tRNA genes, and 3 rRNA genes. The predominant codons for alanine and glutamine are GCU and CAA, respectively, while cysteine and phenylalanine exhibit weaker codon usage biases. The mitogenome contains 73, 34, and 23 simple sequence repeats (SSRs) on chromosomes 1, 2, and 3, respectively. Chromosome 1 exhibits the most frequent A-repeat monomeric SSR, whereas chromosome 2 displays the most common U-repeat monomeric SSR. DNA transformation analysis identifies 48 homologous fragments between the mitogenome and chloroplast genome, representing 3.41% of the mitogenome’s total length. The PREP suite detects 460 C-U RNA editing events across 33 mitochondrial PCGs, with the highest count in the ccmFn gene and the lowest in the rps7 gene. Phylogenetic analysis confirms A. stolonifera ’s placement within the Pooideae subfamily, showing a close relationship to Lolium perenne , consistent with the APG IV classification system. Numerous homologous co-linear blocks are observed in A. stolonifera ’s mitogenomes and those of related species, while certain regions lack homology. Conclusions The unique features and complexities of the A. stolonifera mitochondrial genome, along with its similarities and differences to related species, provide valuable insights into plant evolution, energy production, and environmental adaptation. The findings from this study significantly contribute to the growing body of knowledge on plant mitochondrial genomes and their role in plant biology.

Plants evolve diverse mechanisms to eliminate the drastic effect of biotic and abiotic stresses. Drought is the most hazardous abiotic stress causing huge losses to crop yield worldwide. Osmotic stress decreases relative water and chlorophyll content and increases the accumulation of osmolytes, epicuticular wax content, antioxidant enzymatic activities, reactive oxygen species, secondary metabolites, membrane lipid peroxidation, and abscisic acid. Plant growth-promoting rhizobacteria (PGPR) eliminate the effect of drought stress by altering root morphology, regulating the stress-responsive genes, producing phytohormones, osmolytes, siderophores, volatile organic compounds, and exopolysaccharides, and improving the 1-aminocyclopropane-1-carboxylate deaminase activities. The use of PGPR is an alternative approach to traditional breeding and biotechnology for enhancing crop productivity. Hence, that can promote drought tolerance in important agricultural crops and could be used to minimize crop losses under limited water conditions. This review deals with recent progress on the use of PGPR to eliminate the harmful effects of drought stress in traditional agriculture crops.

Maize is a sensitive crop to drought and heat stresses, particularly at the reproductive stages of development. The present study investigated the individual and interactive effects of drought (50% field capacity) and heat (38 °C/30 °C) stresses on morpho-physiological growth, yield, nutrient uptake and oxidative metabolism in two maize hybrids i.e., ‘Xida 889’ and ‘Xida 319’. The stress treatments were applied at tasseling stage for 15 days. Drought, heat and drought + heat stress caused oxidative stress by the over-production of ROS (O 2− , H 2 O 2 , OH − ) and enhanced malondialdehyde contents, which led to reduced photosynthetic components, nutrients uptake and yield attributes. The concurrent occurrence of drought and heat was more severe for maize growth than the single stress. However, both stresses induced the metabolites accumulation and enzymatic and non-enzymatic antioxidants to prevent the oxidative damage. The performance of Xida 899 was more prominent than the Xida 319. The greater tolerance of Xida 889 to heat and drought stresses was attributed to strong antioxidant defense system, higher osmolyte accumulation, and maintenance of photosynthetic pigments and nutrient balance compared with Xida 319.

Low phosphorus (P) availability and salt stress are two major constraints for maize ( L.) growth in north China. A combination of salinity and high P rather than low P is more detrimental to the growth of maize. However, little is known about the mechanisms by which P nutrition modifies the salt tolerance and P uptake of maize. The present study aimed to investigate the combined effects of salinity and P on maize growth and P uptake, and to address the physiological mechanisms of salt tolerance influenced by P availability in maize. Seedlings of a local maize cultivar XY335 were grown hydroponically for 35 days under low (5 μM) or sufficient P supply (200 μM) with or without 100 mM NaCl. Root morphological traits, tissue mass density, leaf osmolytes (sugars and proline) accumulation, and Na /K ratio were measured to allow evaluation of the combined effects of salinity and P on maize growth and P uptake. Both P deficiency and salinity markedly reduced the growth of maize. However, P deficiency had a more pronounced effect on shoot growth while salinity affected root growth more prominently. Combined effects of P deficiency and salinity on total root length, root surface area, and average root diameter were similar to that of plants grown under salt stress. The combination of P deficiency and salinity treatments had a more pronounced effect on tissue mass density, leaf proline and soluble sugars compared to individual treatment of either low P or NaCl. When exposed to salt stress, maize plants of sufficient P accumulated greater amount of Na than those under P deficit, but similar amounts of K were observed between the two P treatments. Salt stress significantly increased shoot P concentration of maize with sufficient P ( < 0.01), but not for P-deficient plants. In sum, shoots and roots of maize exhibited different responses to P deficiency and salinity, with more marked effect of P deficiency on shoots and of salinity on roots. P deficiency improved salt tolerance of maize plants, which was associated with the increase of tissue mass density, accumulation of osmolytes, reduction of Na accumulation, and selective absorption of K over Na .

A vast microbial community inhabits in the rhizosphere, among which, specialized bacteria known as Plant Growth-Promoting Rhizobacteria (PGPR) confer benefits to host plants including growth promotion and disease suppression. PGPR taxa vary in the ways whereby they curtail the negative effects of invading plant pathogens. However, a cumulative or synergistic effect does not always ensue when a bacterial consortium is used. In this review, we reassess the disease-suppressive mechanisms of PGPR and present explanations and illustrations for functional diversity and/or stability among PGPR taxa regarding these mechanisms. We also provide evidence of benefits when PGPR mixtures, rather than individuals, are used for protecting crops from various diseases, and underscore the critical determinant factors for successful use of PGPR mixtures. Then, we evaluate the challenges of and limitations to achieving the desired outcomes from strain/species-rich bacterial assemblages, particularly in relation to their role for plant disease management. In addition, towards locating additive or synergistic outcomes, we highlight why and how the benefits conferred need to be categorized and quantified when different strains/species of PGPR are used in combinations. Finally, we highlight the critical approaches needed for developing PGPR mixtures with improved efficacy and stability as biocontrols for utilization in agricultural fields.

Salt is one of the main factors limiting the use of mudflats. In this study, the yield, quality, and mineral content of rice seeds under salt stress were investigated. A pot experiment was conducted with Yangyugeng2, Xudao9, and Huageng5 under 0, 17.1, 25.6, and 34.2 mM NaCl of salt concentration treatments. The results showed that salt stress can significantly decrease panicle number, grain number per panicle, 1000-grain weight and yield of rice, and the panicle number was among other things the main cause of yield loss under saline conditions. When the salt concentration is less than 34.2 mM NaCl, the salt stress increases the brown rice rate and milled rice rate, thus significant increasing head milled rice rate of salt-sensitive varieties but decreasing in salt-tolerant varieties. In addition, the grain length is more sensitive than grain width to salt stress. This study also indicates that different varieties of rice exhibit different salt tolerance under salt stress, the three rice varieties in this study, in order of salt tolerance, are Xudao9, Huageng5, and Yangyugeng2. Salt stress will increase the appearance, viscosity, degree of balance, and taste value, and decrease the hardness of rice when salt concentration is less than 17.1 mM NaCl in Yangyugeng2 and Huageng5 or 25.6 mM NaCl in Xudao9. The differences in starch pasting properties among rice varieties in this study are larger than those caused by salt stress. The uptake capacity of K, Mg, P, S, and Cu ions in the seeds of different rice varieties significantly vary, and salt stress causes significant differences in the uptake capacity of K, Na, and Cu ions in rice seeds. Rice varieties with high salt tolerance can be selected for the development and utilization of mudflats, and low concentration of salt stress will increase the rice quality, all of which are meaningful to agricultural production.

Although phosphate-solubilizing bacteria (PSBs) are used in agricultural production, comprehensive research on PSB that colonize the rhizosphere of different plants and promote plant growth is lacking. This study was conducted to examine the growth-promoting effects and colonizing capacity of strain YL6, a PSB. YL6 not only increased the biomass of soybean and wheat in pot experiments but also increased the yield and growth of Chinese cabbage under field conditions. The observed growth promotion was related to the capacity of YL6 to dissolve inorganic and organic phosphorus and to produce indole-3-acetic (IAA) and gibberellin (GA). After applying YL6 to soybean, wheat and Chinese cabbage, the rhizosphere soil available phosphorus (available P) content increased by 120.16%, 62.47% and 7.21%, respectively, and the plant total phosphorus content increased by 198.60%, 6.20% and 78.89%, respectively, compared with plants not treated with YL6. To examine plant colonization, YL6 labeled with green fluorescent protein (YL6-GFP) was inoculated into the plant rhizosphere and found to first colonize the root surface and hairs and then to penetrate into the intercellular spaces and vessels. Collectively, these results demonstrate that YL6 promotes the growth of three different crops and colonizes them in a similar manner. The findings therefore provide a solid foundation for probing the mechanisms by which PSB affect plant growth.