The large-scale deployment of enhanced rock weathering (ERW) in croplands is a promising yet challenging carbon removal strategy. However, the influence of common agronomic management practices on its weathering and carbon sequestration efficiency remains unclear. Based on a six-year field experiment, this study evaluated the effects of tillage (plowing vs. no‐tillage) and organic amendment on the basalt weathering and carbon sequestration from two timescales of short‐term (90‐day) and long‐term (six‐year). Short-term monitoring revealed plowing transiently enhanced soil aeration and respiration, but it did not accelerate Mg²⁺ release. Soil moisture as the key driver of initial weathering process, correlated most strongly with the soil solution Mg²⁺ from basalt (r = 0.787, p < 0.001). Long-term results showed that rock weathering fraction exhibited marked vertical heterogeneity, being 1.52 to 2.95 times higher in the 0–20 cm layer than at 30–50 cm. By enriching basalt in the 0–20 cm layer, no-tillage significantly promoted rock weathering and the accumulation of soil inorganic carbon. Positive effects of ERW on soil organic carbon and mineral-associated organic carbon occurred only with organic amendment treatment, indicating that continuous organic carbon input is a key prerequisite for ERW to enhance soil organic carbon fraction. Factorial analysis revealed that soil biological factors, particularly microbial biomass carbon and low molecular weight organic acids, were the primary drivers of rock weathering vertical heterogeneity, exhibiting stronger correlations and contributions than soil physicochemical factors. Thus, the spatial pattern of weathering is governed by a surface soil "biological engine". This study emphasizes integrating ERW with conservation tillage and organic management to create a "low-disturbance, high-bioactivity, organically synergistic" field environment. The findings provide critical scientific support for incorporating ERW into sustainable agriculture to synergistically address climate change and food security.

Biochar amended soils are considered to be a novel concept to improve soil health by providing favorable habitats for microbial activity. This study carried out field experiments to assess the diversity, composition, and co-occurrence networks of soil bacterial communities in the presence of biochar, in order to validate the optimal amount of biochar addition for the practical application of soil improvement in apple orchards in terms of bacterial interactions. The application of appropriate biochar increased bacterial diversity and the prominent presence of copiotroph bacteria was Proteobacteria, and improved the network complexity and cooperative mutualism of the bacterial ecological networks with enhanced stability and environmental resistance. Biochar addition shifts keystone bacteria from anaerobic and cellulose-degrading bacteria to aerobic and nitrogen cycling-related bacteria. Obtained 2 kg/m2 of biochar-amended soil favors micro-environment optimization with the strongest resource utilization and adaptability of the bacterial community. Biochar as a sustainable soil amendment material and 2 kg/m2 biochar addition has the potential to be a viable approach for soil health improvement in apple orchards.

[目的]为提高氮肥利用效率,减少氮排放,将聚丙烯酰胺与氮肥进行配施,研究相关处理对盆栽苹果苗生理生长、氮排放与土壤特性的影响,为苹果种植采用合理的聚丙烯酰胺用量,提高氮肥利用率提供理论依据.[方法]以烟富3号三年生苹果苗为试验材料,通过盆栽试验分别设置聚丙烯酰胺0 g、25 g、50 g、75 g与氮肥0 g、12.5 g、25 g、50 g组合配施处理,分析氧化亚氮排放通量、铵态氮排放速率,土壤团聚体以及有机质等土壤养分的含量变化.[结果]在同一氮肥水平下,氧化亚氮排放通量与铵态氮排放速率,随着聚丙烯酰胺用量的提高整体呈现下降趋势,在氮排放总量上聚丙烯酰胺可以显著降低氮排放,在12.5 g、25 g、50 g氮肥水平下,施加75 g聚丙烯酰胺的处理相比不施加聚丙烯酰胺的处理,氮排放分别减少了19.44％、30.00％、37.02％;聚丙烯酰胺的施用能不同程度改善土壤理化性质,在12.5 g、25 g、50 g氮肥水平下,土壤中速效氮质量分数均在施用75 g聚丙烯酰胺时达到最高值,分别提高了43.46％、38.35％、30.35％,有机质以及＞0.25 mm的团聚体也表现出相似的趋势,在12.5 g与50 g的氮肥水平下,在施用75g聚丙烯酰胺时有机质含量达到最高值,相比不施用聚丙烯酰胺的处理,增加了37.02％与35.93％;在同一氮肥水平下,施用聚丙烯酰胺的苹果盆栽苗当年新梢增长量、根系总长度、根系面积与体积都显著高于不施加聚丙烯酰胺的处理.[结论]综上所述,聚丙烯酰胺能够有效改善氮排放、土壤特性,促进苹果树生长.

CONTEXT: Farmland enhanced rock weathering (ERW) is a negative emission technology that accelerates CO2 sequestration into the soil inorganic carbon (SIC) sink by applying calcium and magnesium-rich silicate rock to agricultural soils. Farmland ERW has great CO2 removal potential and is accompanied by various co-benefits, such as improving soil pH and providing mineral nutrients. However, the environment-driven mechanisms of ERW remain unclear, and the uncertainty on crop productivity also requires further evaluation in field trials.OBJECTIVE: We tried to explore the response of crop productivity and soil inorganic carbon to ERW in farmland and analyze the contribution and prioritization of environment drivers for the above change.METHODS: A series of monitoring trials were established in a multi-agroclimatic region in central China from 2019 to 2021. Firstly, crop productivity and SIC change mediated by ERW were evaluated by applying 10 kg m 2 mixed rock powder in field trials. Secondly, the random forest and correlation network analysis were used to quantify the influence of climate, soil, and management drivers on yield and SIC change. Finally, the carbon footprint of silicate rock powder was calculated by life cycle analysis.RESULTS AND CONCLUSIONS: Farmland ERW significantly improved the crop yield (7 & PLUSMN; 4.3%) and biomass (11 & PLUSMN; 4.6%) in the whole region. In the low water balance region, the net carbon sequestration during three years caused by ERW was 4.31 & PLUSMN; 0.82 t-CO2 ha 1, which increased the carbon capture of the agricultural system by 1.6-2.4 times. Contribution analysis showed that soil pH had the highest relative importance (18%) on yield change mediated by ERW. Low soil pH was conducive to yield and nutrient effectiveness increases, and the largest yield increase reached 31 & PLUSMN; 6.9%. Water balance (rainfall/evapotranspiration) was the dominant driver affecting (20%) inorganic carbon sequestration, the accumulation of SIC in low water balance reached 3.8 times that in high water balance regions. Moreover, fertilizer input also significantly correlated with ERW field effect, and N input significantly increased the SIC in the arid region.SIGNIFICANCE: This study provided detailed field data for large-scale potential analysis of ERW in farmland. These findings contribute to understanding the environmental influence of ERW and assisting decision-making for ERW layout. Moreover, our results could inspire soil improvement in regions with soil acidification and mineral nutrient shortages.

在苹果生产中,'富士'枝条易旺长,过旺生长的枝条会破坏营养生长与生殖生长之间的协调关系,不利于'富士'苹果的成花,从而造成严重的大小年现象.为防止枝条旺盛生长,缓解大小年结果问题,促进花芽形成,以8 a生'长富2号'为试材,在2020年预备试验的基础上,于2021年5月20日、6月20和7月20日分别进行了 T1(复硝酚钾1 mg·L-1)、T2(亚磷酸钾3 340 mg·L-1)和T3(复硝酚钾1 mg·L-1+亚磷酸钾3 340 mg·L-1)喷施处理,以清水作为对照(CK),对苹果枝条的生长量、短枝顶芽内源激素含量进行测定,对次年成花率进行调查,并用定量PCR对'富士'苹果短枝顶芽内成花相关基因的表达量进行验证.结果表明:从处理后至生长季结束,T2和T3处理可以显著地控制枝条后期的生长,枝条生长量与对照相比分别降低29.03％～31.64％和27.18％～30.33％;激素水平上,花芽从生理分化期到形态分化期,随着喷施次数增加,ZR的含量先增高后降低,IAA和GA3的含量下降,ABA的含量先升高后下降,且在第三次喷施时差异显著;在成花的关键时期,芽内成花促进基因MdSOC1、MdFD、MdLFY和MdFT表达上调,成花抑制基因MdGA20ox和MdTFL-1表达水平被显著下调.喷施复硝酚钾和亚磷酸钾后,与对照相比T3处理下显著提高了次年的成花率,为63.41％左右.综上所述,喷施复硝酚钾和亚磷酸控制枝条旺盛生长,平衡了营养生长与生殖生长的关系,同时调节了内源激素含量变化,促进了成花相关基因的表达,有效地促进了'富士'苹果成花,推荐在适宜留果量下树旺'富士'苹果园中使用.

Enhanced rock weathering (ERW) in farmland is an emerging carbon dioxide removal technology with crushed silicate rocks for soil improvement. However, due to climatic variability and field data limitations, uncertainties remain regarding the influence of ERW on food security and soil carbon pools in temperate regions. This study focused to evaluate the crop productivity and carbon sequestration potential of farmland ERW in China by conducting field monitoring in different humid regions and ERW performance model. Additionally, the contribution of climate, soil, and management factors to ERW-mediated yield and carbon sequestration changes was explored using random forest and correlation networks. Field monitoring indicated that farmland ERW significantly improved crop yield in humid region (13.5 ± 5.2 %), along with notable improvements in soil pH and available nutrients. Precipitation (10.4-16.7 %) and soil pH (9.7-16.8 %) had the highest contribution on ERW mediated yield and carbon sequestration changes, but the contribution of management factors (24-26.2 %), especially N input (2.7-7.0 %), should not be disregarded. The model evaluation demonstrated that the carbon sequestration rate of farmland ERW in China can reach 0.28-0.40 Gt yr-1, thereby presenting an opportunity to expand and accelerate the nationally determined contributions of China. The mean sequestration cost of farmland ERW was 633 ± 161 CNY ¥ t-CO2-1, which was an attractive sequestration price considering the positive benefits of rock powder on soil pH and nutrients. Deploying ERW in acidified and mineral nutrient deficient regions was able to serve as an alternative to lime and part chemical fertilizers to improve yield and maximize agricultural sustainability and resource co-benefits. Farmland ERW also has the potential to resource silicate waste to assist traditional, difficult-to-decarbonize industries to reduce carbon emissions. As a result, a comprehensive assessment of existing artificial silicate waste materials could further expand the application of farmland ERW.

研究了喷施亚磷酸钾对富士苹果黑星病的预防效果.试验结果发现喷施亚磷酸钾3～4次对苹果黑星病发生有一定的预防控制效果,与对照组相比,亚磷酸钾对预防黑星病的发生起到了良好的作用,能降低中后期苹果黑星病发生程度25％～35％左右.亚磷酸钾可推荐作为黑星病预防药剂的补充肥料,建议与内吸性杀菌剂配合或交替使用.

【Objective】 The canopy growth law of high-spindle apple tree was studied to provide reference for the management of high-spindle apple trees.【Method】 The spur Fuji on M26 interstock was selected and three treatments of 4-,8-and 12-year-old trees were included to obtain basic canopy information and branch structure.A virtual tree model of apple trees at three ages was constructed for comparison of physical tree photo and virtual tree.The total leaf area（TLA）,projected leaf area（PLA）,silhouette to total leaf area ratio（STAR）,leaf area index（LAI） and other indicators of fruit tree canopy were calculated based on the constructed 3D model, and virtual orchards at three different ages were established to calculate light interception efficiency.At last, the leaf area index of each canopy layer was measured by the canopy analyzer LAI-2000 and compared with the model calculation.【Result】 There was no significant difference in branch structure between field investigation and digital results, and the digitally obtained branch group structure was more accurate.Compared with actual tree photo, the virtual tree image showed the actual growth of trees as a whole.The TLA of fruit tree canopy of the three ages were 6.41 m~2,11.60 m~2 and 19.69 m~2 and their PLA were 2.38 m~2,3.88 m~2 and 5.77 m~2,both increased significantly with the growth of tree.The STAR values were 0.37,0.33 and 0.29 without significant difference among ages, and the LAI values were 1.78,3.87 and 3.28, respectively. In the virtual orchard, the simulated STAR values were 0.30,0.18 and 0.19,and 4-year-old trees had significant difference with 8-and 12-year-old trees.The root mean square error（RMSE） between the LAI-2000 measured canopy leaf area index values and the 3D model calculated values was 0.171,indicating high model accuracy.【Conclusion】 The saplings of Fuji apple trees had good light interception efficiency.The light interception efficiency of individual fruit trees decreased insignificantly with the growth of tree age, and the light interception efficiency in older orchards decreased more than younger orchards.It is recommended to control reasonable planting density and branch and leaf density to improve canopy light distribution in aged orchards.

Water deficit episodes impact apple (Malus domestica) productivity through challenging the trees' water status, the influence of extreme high temperature climate has become increasingly prominent in recent years. Rootstocks can bestow specific properties on the fruit trees such as the resistance to drought stress. However, the related hydraulic mechanisms in response to water deficit have not been fully understood. Herein, five rootstocks (SH6, GM256, M9, M26, and MM106) were examined under water limitation. The hydraulic conductance of root (Kroot), shoots (Kshoot), and stems (Kstem-shoot) in the five rootstocks reduced slightly during drought stress. Whereas the leaf water potential and photosynthesis of five rootstocks decreased dramatically when they were exposed to drought stress. Additionally, the Kshoot and Kstem-shoot were strongly correlated with the total plant leaf area. Aquaporins (AQPs) involved in the symplastic water transport pathway, the PIP2:1, TIP1:1, and TIP2:2 mRNA levels of all genotypic rootstocks showed significant regulation under drought stress. We examined the relationships among photosynthesis, apoplastic, and symplastic water movement pathways to achieve a comprehensive understanding of rootstocks' hydraulic strategy for improving drought adaptation. The PIP2:1 and TIP2:1 in leaves were more sensitive to root hydraulic conductance in response to drought stress. Furthermore, the coordinated relationship existed in leaf-specific conductance of shoot (Kl-shoot) and transpiration rate (Tr) under drought stress in the rootstocks. Overall, the drought resistance in the five dwarfing rootstocks is associated with the rapid re-establishment of water-related traits, and the effect of the canopy on the drought resistance in apple rootstocks merits much more attention.

【Objective】‘Qincui’ is the hybrid offspring of ‘Honeycrisp’, bitter pit（BP） is often observed in the production, which has an negative impact on the production. When BP is serious, the commodity rate of fruit will decrease, which will lead to greater economic losses. Therefore, this experiment was carried out to explore the appropriate plant growth regulator to prevent BP.【Methods】Different concentrations of 5-aminolevulinic acid（5-ALA） and 250 mg/L prohexadione-calcium were tested on ‘Qincui’ apple, and the preventive effect on BP of ‘Qincui’ apple was studied and analyzed.【Results】The results showed that 5-ALA combined with prohexadione-calcium had a certain preventive and control effect on the occurrence of BP in ‘Qincui’ apple. The incidence of 5-ALA with 4 sprays of 100 mg/L combined with 250 mg/L prohexadione-calcium in late July was 5.5%. Compared with the control, the incidence of BP was reduced by 56%. And spraying 100mg/L of 5-ALA can improve photosynthesis and transpiration.【Conclusion】The comprehensive analysis has shown that spraying 5-ALA and prohexadione-calcium had a certain preventive effect on BP of ‘Qincui’ apple.

Based on the sustainable development practice-zero growth in chemical fertilizer application, this article used bagasse organic fertilizer and rice husk derived biochar to investigate the response of soil bacterial community in apple orchard. Aimed at realize the soil quality improvement and biomass resource recovery to contribute agricultural and environmental sustainability. The co-trophic Proteobacteria was predominant in all the treatments (29-36 %) and enriched in non-nitrifying Alphaproteobacteria (9-11 %) and ammonia oxidant Betaproteobacteria (8-10 %), especially richest in bagasse fertilizer combine biochar treated soil. In addition, bacterial community variation was assessed by alpha and beta diversity, four treatments dispersed distribution and richer abundance observed in combined apply bagasse fertilizer and biochar treatment (3909.22 observed-species) than single application (3729.88 and 3646.58 observed-species). Biochar as microbial carrier combined organic fertilizer were established synergistic interaction and favorable to organic matter availability during sustainable agriculture. Finally, integrated biochar-bagasse fertilizer was richer than single organic or biochar fertilization in improving soil bacterial diversity, notably by promoting the metabolism of copiotrophic bacteria, nutrient cycling, plant growth and disease inhibit-related bacteria.

The dry soil layer (DSL), as a typical indicator for degradation in soil water supply capacity and soil drought, could provide important information for land use and reconstruction in semiarid and arid areas. However, the traditional index of DSL assessment neglected the water absorption characteristics and drought resistance of different crops and lacked uniformity and comparability. These may misjudge the occurrence and severity of the DSL and bring uncertainty to land development and vegetation selection. In this study, the DSL severity of the main production zone of apples in the Chinese Loess Plateau was reassessed using new plant physiological indices covering the next 60 years (2020-2080) under four general circulation models. Physiological indices were established based on the response of leaf net photosynthetic (T-PN) and transpiration rate (T-TR) to soil available water which is the difference between soil moisture and permanent wilting point (n = 113). The environment policy integrated climate (EPIC) model was used to predict future soil water dynamics and drought yield loss (YL). The results showed that T-PN and T-TR significantly slowed down the accumulation of DSL severity quantitative index (QI, based on thickness moisture and formation depth of DSL) and enhanced the correlation between DSL and YL, which correlation coefficient increased from 0.51 to 0.73 and 0.64. Forming serious DSL (QI >0.5) has slowed from 2040 to 2055 years. Moreover, future climate change accumulatively reduced 9.95%-14.18% of the YL. These results indicated that the traditional method overestimated the environmental contradiction between economic benefits and eco-hydrology of apple orchards, which could send unreliable messages to policymakers to restrict further development of apple industries. This study emphasized that evaluating DSL based on plant physiological threshold reflected better soil desiccation level and YL, which will contribute to further study of the sustainable development of fragile ecosystems.

Present study evaluated the utilization of clean technology for biochar combined with organic fertilizer in apple orchard aspect of soil organic carbon fractions and microbial community. Four treatments were performed with control (CK), rice husk biochar alone (B), bagasse fermented organic fertilizer alone (O) and biochar combined with organic fertilizer (BO). The results demonstrated that utilization of organic fertilizer integrated with biochar were obviously enhanced the total and active fractions organic carbon in the top-soil (0e20 cm), enriched the bacterial community diversity and the richest abundance presented in BO treatment with 4253 operational taxonomic unit. The visualization illustrated the superior bacterial community was affiliated with Proteobacteria (35.14%), Actinobacteria (21.34%), Acidobacteria (16.82%) and Firmicutes (14.70%). Additionally, redundancy analysis suggested the strong interaction between microorganisms and organic carbon fractions. Overall, the application of biochar combine with organic fertilizer was favorable approach in apple orchard management, attributed to the influence of essential factors by improve organic carbon and bacterial diversity especially conductive to the profitable strain proliferation. (c) 2021 Elsevier Ltd. All rights reserved.

The Squamosa promoter binding protein (SBP)box genes encode a kind of plant-specific transcription factors, and play important roles in plant growth, development, biotic and abiotic stress. Although the genome-wide analysis of SBP-box gene family has been performed in some species, SBP-box gene family in kiwifruit (Actinidia chinensis Planch.) remains poorly understood. In this study, 25 SBP-box genes of kiwifruit were identified in the kiwifruit genome. Based on phylogenetic and comprehensive bioinformatics analysis, 25 kiwifruit SBP-box genes can be classified into eight groups. Additionally, detailed gene structure, conserved domain, motif compositions, and phylogenetic relationship of the AcSBP genes were systematically characterized. Synteny analysis indicated that segmental duplication has likely contributed to the expansion and evolution of the AcSBP genes. Expression analysis revealed that all the AcSBP genes showed distinct expression levels in five different tissues, and suggested AcSBP genes are significantly involved in response to different plant hormone, drought, salt, and Psa treatments to mimic biotic and abiotic stresses. The genome-wide identification and characterization of SBP-box gene family could facilitate the functional analysis ofAcSBP genes and provide information of the molecular basis of development and stress tolerance in kiwifruit.

The shoot growth of ‘Fuji’ apple is vigorous, which causes a poor lighting condition and a high cost to prune. Prohexadione-calcium (ProCa) has been proven to regulate the shoots growth, fruits and return flowering in apple abroad but there are fewer studies on its effect on the shoot growth, fruits and return flowing in ‘Fuji’ apple in China. Moreover, the mechanism of its action is incompletely understood. So different treatments were applied as foliar sprays to dwarf self-rooted ‘Fubrax Red Fuji ’/M9-T337 trees at 3, 14, 35 and 56 DAPF (Days after petal fall). The results showed that at the end of the growing season, spraying ProCa effectively inhibited the growth of shoots compared to control and one spray of 500 and 750 mg L-1 ProCa, two sprays of 250 mg L-1 ProCa and four sprays of 250 mg L-1 ProCa showed the highest reduction. ProCa had very slight effect on yield, quality and return flowing. During the growing season, two applications of ProCa of 250 mg L-1 on 3 and 14 DAPF significantly reduced the content of GA 1+3 , IAA and ZR but increased the content of ABA in long terminal shoot leaves in at least one time point. The expression patterns of GA-regulated genes showed that ProCa down-regulated MdGA3ox transcript level at 10, 20, 30, 40 and 50 DAPF and down-regulated MdCPS, MdGA20ox, MdRGL1a, MdSLY1 transcripts in at least one time point. This study provided a valuable insight to regulate the vegetative growth of ‘Fuji’ apple and explored the mechanism of ProCa action.

Improving the utilization efficiency of rainwater resources was a key issue for apple orchards in semi-arid areas. The RCIP-SA system combined rainwater collection systems, infiltration promoting tube and soil anti-seepage layer to gather limited rainwater resources into the soil layer where the roots of apple tree were concentrated. To evaluate the effect of the RCIP-SA system on soil moisture change and fine root distribution, a field experiment was completed in a hilly apple orchard on the Loess Plateau of China from 2017 to 2019. The results showed that the soil moisture of the RCIP-SA system was 24.0-43.9% higher than CK in the 0-60 cm soil layer in the rainwater collection ditch, and generated a larger area with higher moisture content near the impermeable layer during the apple tree growth period. The RCIP-SA system also expanded the dense distribution zone of apple tree roots. The dry fine root densities of apple trees in the RCIP-SA system in the 0-200 cm soil layer was 11.7-59.6% and 18.2-30.3% higher than CK under the plastic film (60 cm from the trunk) and edge of the rainwater collection ditch (100 cm from the trunk), respectively. Soil moisture and root distribution of apple trees were significantly different under different impermeable layers, and compacted red clay as the impermeable layer was the best anti-seepage strategy in RCIP-SA systems. The RCIP-SA system brought higher economic benefits; the average yield per tree was recorded for red clay compaction treatment (38.1 kg.tree(-1)), equating to a production level of 22 800 kg.ha(-1), and a difference of 9.6 kg.tree(-1) with CK treatment, equating to 5700 kg.ha(-1). This strategy should be recommended as an agricultural measurement for apple production on the Loess Plateau of China.

The eddy covariance (EC) technique was used to measure variations of orchard-atmosphere CO2 exchange, as a function of meteorological variables in an apple orchard in 2016–2017. The annual average CO2 exchange rate was 2.295 kg m−2. Excavations and biomass assessments demonstrated that the orchard stored close to 20.6 tC ha−1 as plant C over a 15-year period. Seasonally, high rates of CO2 uptake and low CO2 emissions occurred between May and August and December and March, respectively. The maximum rates of monthly CO2 exchange were 144.44 and 153.61 gC m−2 month−1 in August 2016 and June 2017, respectively. Partial least squares (PLS) regressions were used to analyze the influence of meteorological factors to on CO2 exchange rates. Temperature and photosynthetic active radiation (PAR) were observed to exert the largest influence on driving variation in CO2 exchange. The main meteorological factors affecting CO2 exchange on daily and monthly time scales were soil temperature (Tsoil), air temperature (Ta), PAR, below canopy CO2 concentration (BCC), vapor pressure deficit (VPD), and soil water content at 50 cm (SWC50cm). The regression model equation describing CO2 exchange included Ta, VPD, precipitation (PPT), and sunshine duration (SD), as significant variables. This model curve fitting explains over 80% of the variation in CO2 exchange. This study provides CO2 exchange characteristics and a model equation capable of predicting CO2 exchange of an apple orchard.

The Loess Plateau is the largest apple cultivation region in the world. However, the role of rain-fed apple orchards as carbon sinks or sources, including the dynamic variation and influencing factors, are still unclear. In this study, the net ecosystem CO2 exchange (NEE) was monitored by an eddy covariance (EC) system in Loess Plateau apple orchards during 2016–2017. The results demonstrated that the annual NEE was higher in 2016 (− 698.0 g C m−2 year−1) than in 2017 (− 554.0 g C m−2 year−1). Particularly, the amount of orchard CO2 uptake was significantly greater in 2016 (− 772.0 g C m−2) than in 2017 (− 642.1 g C m−2) during the carbon sink period. This difference may be attributed to the higher NEE in 2016 compared to 2017 during the fast and slow growth periods. In addition, a higher daily NEE occurred to the higher air temperature (Ta), which promoted early sprouting in 2016 (− 3.91 g C m−2 day−1) compared to 2017 (− 2.86 g C m−2 day−1) during the fast growth period. The daily NEE in 2016 (− 2.59 g C m−2 day−1) was remarkably higher than that in 2017 (− 1.41 g C m−2 day−1) during the slow growth period, owing to the greater number of cloudy and rainy days and lower temperatures in 2017. Overall, the present study demonstrated the key role played by the amount of precipitation and temperature in regulating the NEE during the growth season and provided accurate quantitative information on the carbon budget in apple orchards.

Within the Chinese Loess Plateau, water resources are scarce and irrigation efficiency is a challenging issue. Traditional surface drip irrigation (SDI) methods have failed to improve irrigation efficiency and reduce surface evaporation in the region. An easy‐to‐install and practicable root‐zone injection irrigation (RII) method, with a low risk of emitter clogging and which uses subsurface infiltration‐promoting apparatuses (SIPA) to deliver water directly to the root zone, was designed and tested in an apple orchard over 3 years in northern Shaanxi, China. In the 0–0.6 m soil layer (where the apple roots are concentrated), the RII method produced consistently higher soil water content than the SDI method over all three growing seasons. The soil water content was consistently higher than 60% of field capacity, thus meeting the water requirements of fruit‐bearing apple trees. In addition, the RII method alleviated soil desiccation, significantly increased apple yields and improved fruit quality compared with the SDI method using the same volume of irrigation water. Both irrigation efficiency and water‐use efficiency were improved with the RII method. These results provide a theoretical basis for the utilization of the RII irrigation method in apple orchards in semi‐arid regions, which may improve water conservation and the sustainability of apple production. © 2019 John Wiley & Sons, Ltd.

以‘长富2号’苹果短枝顶芽为材料,采用同源重组法克隆得到成花抑制蛋白SHORTVEGETATIVE PHASE (SVP)家族的1个关键基因MdMADS50,开放阅读框(ORF)长度为675 bp,编码224个氨基酸.序列分析发现,该基因含有1个保守的MADS-box结构域和1个K-box结构域,属于MIKC型.氨基酸多重序列比对和系统进化分析表明,MdMADS50蛋白序列与苹果MdSVP具有较高的同源性.qRT-PCR分析结果表明,MdMADS50具有组织表达特异性,在苹果芽和叶中表达量较高.外源GA3处理促进了MdMADS50的表达,且在难成花品种‘长富2号’苹果芽中的表达量显著高于其他苹果品种.另外,GUS活性检测结果表明MdMADS50基因启动子具有启动活性,且受外源GA3诱导后活性增强.综上,研究表明MdMADS50可能响应GA3处理对苹果成花诱导发挥抑制作用,并介导赤霉素信号参与苹果花芽孕育的调控.