The impact of free-air CO_2 enrichment (FACE) and N supply on growth, yield and quality of rice crops with large panicle

Because CO_2 is needed for plant photosynthesis, the increase in atmospheric [CO_2] has the potential to enhance the growth and development of plant. However, the resultant effects on growth, yield and quality of field-grown rice remain unclear, especially under differing nitrogen (N) availability and/or using cultivars with large panicles. To investigate these, a Free-Air CO_2 Enrichment (FACE) experiment was performed at Wuxi, Jiangsu, China, in 2001-03. A japonica cultivar with large panicle was exposed to two [CO_2] (ambient, ambient+200μmol mol^) at three levels of N supply (15, 25, 35gNm^). FACE accelerates phenology significantly, with 3-5 days earlier in heading and 6-9 days earlier in maturity across 3 years. FACE significantly increased the grain yield by 12.8%, which was mainly due to substantially increased panicle number per square meter (+19%) as result of significant increases in tillering occurrence speed. However the spikelet number per panicle was greatly reduced (-8%), which was due mainly to the significant increase in degenerated spikelets per panicle (+52%) while differentiated spikelets per panicle showed no change. Overall DM accumulation at harvest was stimulated somewhat more (+16%) by FACE, compared to grain yield, by an average of 13% by FACE, thus resulting in 3% reduction in harvest index. FACE caused significant reduction in shoot N concentration (-7%) and significant increase in P concentration (+14%) at grain maturity, resulting in significant increase in N use efficiency and significant reduction in P use efficiency. Both shoot N uptake (+9%) and P uptake (+33%) showed significant increase at harvest, which was mainly due to significant enhanced N and P uptake during early growth stage. On a per plant basis, FACE significantly increased cumulative root volume, root dry weight, adventitious root length and adventitious root number at heading, which was mainly associated with significant increases in root growth rate during early growth period, while total surface area, active adsorption area and root oxidation activity per unit root dry weight showed significant reduction. As for grain quality, FACE cause deterioration of processing suitability and appearance quality drastically, the nutritive value of grain was also negatively influenced by FACE due to a reduction in grain protein and Cu concentration. By contrast, FACE resulted in better eating/cooking quality. For most cases, no [CO_2]×N interaction was detected for the growth, yield and quality parameters. Data from this study has important implications for fertilizer (e.g. N, P) management and variety selection in rice production systems under future elevated [CO_2] conditions.Special Revie

Elevated atmospheric CO2 concentration triggers redistribution of nitrogen to promote tillering in rice

Elevated atmospheric CO2 concentration (eCO2) often reduces nitrogen (N) content in rice plants and stimulates tillering. However, there is a general consensus that reduced N would constrain rice tillering. To resolve this contradiction, we investigated N distribution and transcriptomic changes in different rice plant organs after subjecting them to eCO2 and different N application rates. Our results showed that eCO2 significantly promoted rice tillers (by 0.6, 1.1, 1.7, and 2.1 tillers/plant at 0, 75, 150, and 225 kg N ha−1 N application rates, respectively) and more tillers were produced under higher N application rates, confirming that N availability constrained tillering in the early stages of growth. Although N content declined in the leaves (−11.0 to −20.7 mg g−1) and sheaths (−9.8 to −28.8 mg g−1) of rice plants exposed to eCO2, the N content of newly emerged tillers on plants exposed to eCO2 equaled or exceeded the N content of tillers produced under ambient CO2 conditions. Apparently, the redistribution of N within the plant per se was a critical adaptation strategy to the eCO2 condition. Transcriptomic analysis revealed that eCO2 induced less extensive alteration of gene expression than did N application. Most importantly, the expression levels of multiple N-related transporters and receptors such as nitrate transporter NRT2.3a/b and NRT1.1a/b were differentially regulated in leaf and shoot apical meristem, suggesting that multiple genes were involved in sensing the N signal and transporting N metabolites to adapt to eCO2. The redistribution of N in different organs could be a universal adaptation strategy of terrestrial plants to eCO2

Outbred genome sequencing and CRISPR/Cas9 gene editing in butterflies

Butterflies are exceptionally diverse but their potential as an experimental system has been limited by the difficulty of deciphering heterozygous genomes and a lack of genetic manipulation technology. Here we use a hybrid assembly approach to construct high-quality reference genomes for Papilio xuthus (contig and scaffold N50: 492 kb, 3.4 Mb) and Papilio machaon (contig and scaffold N50: 81 kb, 1.15 Mb), highly heterozygous species that differ in host plant affiliations, and adult and larval colour patterns. Integrating comparative genomics and analyses of gene expression yields multiple insights into butterfly evolution, including potential roles of specific genes in recent diversification. To functionally test gene function, we develop an efficient (up to 92.5%) CRISPR/Cas9 gene editing method that yields obvious phenotypes with three genes, Abdominal-B, ebony and frizzled. Our results provide valuable genomic and technological resources for butterflies and unlock their potential as a genetic model system

Progress of Research on the Physiology and Molecular Regulation of Sorghum Growth under Salt Stress by Gibberellin

Plant growth often encounters diverse abiotic stresses. As a global resource-based ecological problem, salinity is widely distributed and one of the major abiotic stresses affecting crop yields worldwide. Sorghum, a cereal crop with medium salt tolerance and great value for the development and utilization of salted soils, is an important source of food, brewing, energy, and forage production. However, in soils with high salt concentrations, sorghum experiences low emergence and suppressed metabolism. It has been demonstrated that the effects of salt stress on germination and seedling growth can be effectively mitigated to a certain extent by the exogenous amendment of hormonal gibberellin (GA). At present, most of the studies on sorghum salt tolerance at home and abroad focus on morphological and physiological levels, including the transcriptome analysis of the exogenous hormone on sorghum salt stress tolerance, the salt tolerance metabolism pathway, and the mining of key salt tolerance regulation genes. The high-throughput sequencing technology is increasingly widely used in the study of crop resistance, which is of great significance to the study of plant resistance gene excavation and mechanism. In this study, we aimed to review the effects of the exogenous hormone GA on leaf morphological traits of sorghum seedlings and further analyze the physiological response of sorghum seedling leaves and the regulation of sorghum growth and development. This review not only focuses on the role of GA but also explores the signal transduction pathways of GA and the performance of their responsive genes under salt stress, thus helping to further clarify the mechanism of regulating growth and production under salt stress. This will serve as a reference for the molecular discovery of key genes related to salt stress and the development of new sorghum varieties

The experiences of reproductive concerns in cancer survivors: A systematic review and meta‐synthesis of qualitative studies

Abstract Aim The aim of this study was to synthesize qualitative research evidence on cancer survivors' experiences with reproductive concerns (RC). Methods We conducted a systematic search of qualitative studies and utilized the meta‐aggregation approach. The database searches were extended up to May 14, 2023, encompassing 12 databases, specifically MEDLINE, CINAHL, PubMed, EMBASE, Scopus, Web of Science (Core Collection), AMED, PsycINFO, The Cochrane Library, CNKI, Wan Fang Data, and VIP. Results Three overarching themes were synthesized from the analysis of 21 studies that explored cancer patients' awareness of reproductive concerns, their perceptions, needs, and coping styles. These themes encapsulate the multifaceted aspects of cancer patients' reproductive concerns: “Gender differences in fertility concerns among cancer patients: Perspectives from men and women”; “The influence of age: Experiences with fertility issues among cancer patients at different life stages”; “The impact of treatment stages on fertility concerns: The evolution of perception and coping strategies in the course of cancer treatment”. Conclusion Our study presents an in‐depth exploration of the reproductive concerns experienced by cancer patients from various perspectives. We found that the internal experiences of reproductive concerns, their perceptions, needs, and coping mechanisms differ based on their roles. This comprehensive understanding of the complex emotions and needs of cancer patients when confronted with fertility issues can guide clinicians in providing more effective medical assistance, psychological counseling, and fertility‐related information services

Genotypic Differences in Dry Matter Accumulation, Nitrogen Use Efficiency and Harvest Index in Recombinant Inbred Lines of Rice under Hydroponic Culture

To examine the possibility of breeding high-yielding cultivars with high nitrogen use efficiency for dry matter accumulation (NUEd) and to provide simple criteria for the selecting and breeding high-yielding cultivars with high NUEd as well as useful information for the mapping of quantitative trait loci (QTL) controlling NUEd, we cultured recombinant inbred lines (RILs) of rice hydroponically in 2000 and 2001. RILs with a higher grain yield tended to show greater total dry matter accumulation (TDMA) and higher harvest index (HI), while increasing TDMA resulted in a decrease in HI. The contribution ratio of the TDMA to grain yield (2000 : 67.3%, 2001 : 68.2%) was higher than that of HI in both 2000 and 2001. Even at the same high-yielding level, there was a significant difference in the TDMA and HI values. In both years, the contribution ratios of NUEd and total nitrogen absorption (NTA) to TDMA were about 62.0 and 38.0%, respectively. The contribution ratio of the NUEd to grain yield was higher than those of the NTA and HI in both 2000 (41.6%) and 2001 (42.9%). These results suggested that the high-yielding rice plants generally displayed high TDMA and HI values. Further increase in rice grain yield should be based on the further increase in TDMA than in HI, and to increase TDMA leading to a high grain yield, the emphasis also should be put on improving NUEd in RILs

The mitochondrial genome of a leaf insect Phyllium westwoodii (Phasmatodea: Phylliidae) in Southeast Asia

The nearly complete mitochondrial genome (mitogenome) of Phyllium westwoodii, a typical leaf mimic insect in Phasmatodea, was obtained in this study. This mitogenome is 17,222 bp in length and contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and almost complete control regions. All PCGs initiate with ‘ATN’ except for NAD4L that uses ‘TTG’ as the start codon, and terminate with ‘TAA’ except for COX2 that uses a single ‘T’ residue as the stop codon. The phylogenetic analysis based on the concatenated sequences of 13 PCGs and two rRNAs shows that P. westwoodii is closer to Phyllium tibetense than Phyllium giganteum

The Effects of Planting Density and Nitrogen Application on the Growth Quality of Alfalfa Forage in Saline Soils

Soil salinization has become one of the major abiotic stresses limiting agricultural production globally. The full utilization of coastal saline-alkali land is of great significance for agricultural development. Among them, fertilizer management and planting density are crucial for promoting crop growth and productivity in saline soils. Field experiments were conducted to study the effects of different nitrogen application rates and planting densities on the growth, yield, and quality of alfalfa. Using alfalfa variety WL919 as the experimental material, three seeding rates of 15.0 kg·ha−1 (D1), 30.0 kg·ha−1 (D2), and 45.0 kg·ha−1 (D3) as well as three nitrogen application rates of 150.0 kg·ha−1 (N1), 225.0 kg·ha−1 (N2), and 300.0 kg·ha−1 (N3) were set. The results showed that under the same density, different nitrogen application rates had a positive impact on the agronomic traits and yield of alfalfa on saline-alkali land. Physiological and biochemical properties (chlorophyll and sucrose) increased with increasing nitrogen application, and (starch) increased initially and then decreased with increasing nitrogen application. Forage quality attributes (crude protein and crude ash) had a significant impact, while crude fat had no significant effect. Under the same nitrogen application, the yield of alfalfa increased with increasing density but then decreased after reaching a peak, while other traits initially increased and then decreased. In conclusion, the nitrogen fertilizer was superior in promoting alfalfa growth, biomass yield, and forage yield, while planting density was more suitable at D2. Although both D2N2 and D2N3 treatments were superior to others, considering economic benefits and environmental factors, it is recommended to use D2N2 as the appropriate treatment