The number of pistils determines the yield of Chinese chestnut (Castanea mollissima Bl.). However, the candidate pathways associated with formation of multi-pistil female flower clusters (MFF) remain largely unclear. This study integrated morphological, anatomical, transcriptomic, and targeted phytohormone metabolomic approaches to compare MFF and normal female flower clusters (NFF). The results showed that MFF exhibited longer basal bracts with fewer basal trichomes. The critical stage for multi-pistil phenotype formation occurred during pistil primordium differentiation, when additional floral meristems continuously expanded and differentiated into new flower primordia. Auxin (IAA), cytokinin (CTK), jasmonic acid (JA), and gibberellin (GA) were identified as potentially associated with this. Candidate genes associated with hormone biosynthesis, signal transduction, and core transcription factors regulating floral organ development at this key developmental stage were also identified. The findings of this study provide insights into the potential regulatory mechanisms underlying the differentiation and development of MFF.

Castanea mollissima Bl. is rich in nutrition and strong in stress resistance, and has nutritional, economic, and ecological values. A protoplast is impactful in somatic fusion and germplasm creation. Here, we propose an effective scheme for the construction of an embryonic suspension cell, protoplast isolation, and fusion. Studies have shown that when 1.0 g yellow loose embryonic callus was inoculated into MS + 1.5 mg∙L−1 6-BA + 0.2 mg∙L−1 NAA + 0.5 mg∙L−1 2, 4-D liquid medium, a stable suspension cell line can be obtained. After further culturing for 2–4 days, protoplast isolation was performed. First, single-factor screening was conducted on the four enzymes, and then a two-factor random block was further set up to screen the enzyme combinations based on the results. We found that 1.0%cellulase R-10 + 0.5%pectolase Y-23 led to the highest protoplast yield (9.27 × 106/g FW) and the highest activity (92.49%). Furthermore, the protoplast yield could be increased to 9.47 × 106/g FW by adding 0.4 M mannitol and shaking for 8 h. The protoplasts were purified by centrifuging at 40× g for 4 min and then mixed with 30% PEG 6000 at a volume ratio of 1.5:1 for 25 min. The fusion rate could reach 70.00%. This study laid a foundation for the creation of new germplasm by Castanea mollissima Bl.

This study aimed to compare the photosynthetic physiological traits, fruiting characteristics, and fruit quality of four different chestnut cultivars. The cultivars studied were ‘Yanshanzaofeng’ (YS), ‘Guangdedahongpao’ (GD), ‘Chang’anhuijianli’ (CA), and ‘Guizhouyouli’ (GZ). Leaf functional traits, photosynthetic activity, fruit setting characteristics, and both external and internal fruit quality indicators were measured. The results indicated significant differences in leaf traits among cultivars. Cultivar GD exhibited the largest leaf area and dry matter content, while cultivar GZ had the smallest. The photosynthetic rate (Pn) followed a bimodal curve, with an obvious ‘lunch break’ caused by stomatal limitations. Cultivar GD had the highest Pn, followed by CA, YS, and GZ. The water use efficiency (WUE) and CO2 utilization of cultivar CA were notably superior, indicating its suitability for arid conditions. In terms of yield, cultivar GD had the highest bur, nut weight, and plant yield, followed by CA, YS, and GZ. The phenotypic quality of the fruit was also superior in cultivar GD. However, cultivar YS had the highest amylopectin and soluble sugar content, and cultivar GD had the greatest amylose, total starch, and fat content. Cultivars CA and YS exhibited better overall fruit quality than GZ. Correlation analysis revealed that single bur weight, single nut weight, and single plant yield all exhibited highly significant or significant positive correlations with Pn, stomatal conductance (Gs), intercellular CO2 concentration (Ci), and the transpiration rate (Tr). The longitudinal diameter of burs showed a significant positive correlation with vitamin C (Vc), Pn, and Gs, with a correlation coefficient of 0.99. Additionally, both the transverse and longitudinal diameters of nuts were significantly positively associated with Pn and Ci. Furthermore, the total starch content and water content of nuts demonstrated a significant positive correlation with Pn. In conclusion, cultivar GD was found to be ideal for high-yield starch production, while cultivar YS offers superior sweet and waxy nut qualities. Cultivar CA presents a balance of photosynthetic capacity, yield, and quality, making it the second-best candidate. Cultivar GZ is unsuitable for large-scale cultivation.

[目的]为解决板栗生产中品种混淆、利用率低等问题,采用几何形态测量法对不同板栗品种坚果形态进行数字化分析,建立板栗品种鉴别方法.[方法]以我国不同板栗主产区的80个品种,共3200个坚果为试验材料,统一参数对其平面、侧立面、底部组分别进行拍照.利用Image J软件,结合板栗坚果形态特征,按照一致顺序选择34个鉴定点,以此获得坚果形态坐标数据.利用Morpho J软件将数据进行普氏叠印分析,消除大小、位置等非形态因子的干扰,并以品种进行分类;对坐标数据进行相对扭曲分析,得到34个鉴定点的贡献率,以此提取重要鉴定点;通过主成分分析,将不同品种间坚果形态差异可视化,进行典型变量分析和判别分析,获得不同组分对不同板栗品种的鉴别效果.[结果](1)相对扭曲分析显示,前25个鉴定点累计贡献率为87.7％,有较大的鉴别作用,作为重要鉴定点.(2)主成分分析显示,坚果的形态差异主要体现在果顶果肩、坚果平面轮廓形态、坚果厚度和底座相对大小.(3)典型变量分析显示,以不同组分单独进行鉴别时,大部分品种存在重合现象,区分度较低;以34个鉴定点综合鉴别时,不同品种间均有显著的区分,鉴别效果明显;以25个重要鉴定点进行鉴别时,效果与前者相似.(4)80个板栗品种以不同组分单独进行判别分析时,平面、侧面、底部组分正确率分别为72.5％～100.0％、71.8％～100.0％、70.0％～100.0％;以34个鉴定点进行综合判别,正确率为95.0％～100.0％;以25个重要鉴定点进行判别,正确率为92.5％～100.0％,后两者具有较高的判别率,能够实现80个板栗品种的鉴别.[结论]基于25个重要鉴定点的几何形态测量分析可实现不同板栗品种的准确鉴别,正确判别率达92.5％～100.0％,本研究建立了基于坚果形态数字化分析的板栗品种鉴别方法,将为生产实践中品种的正确应用提供新依据.

[目的]为解决生产中板栗品种易混淆、辨别困难等问题,采用几何形态测量法对不同板栗品种叶形进行数字化分析,建立板栗品种叶形鉴别方法.[方法]以来自我国不同板栗产区的80个品种叶片为试验材料,2年间重复采集叶样,每年6400张.通过扫描获取叶片图像,采用几何形态测量法及Image J软件,结合板栗叶片特征,选取24个鉴定点并按照一致顺序获取叶形坐标数据.利用Morpho J软件将叶形数据以产区、品种进行分类,进行普氏叠印分析将叶片大小与形状因子分离,进一步形成对称及非对称组分.对数据进行主成分分析、偏最小二乘法的异速生长分析并结合网格变化图将不同品种间叶形差异可视化,同时依据鉴别贡献率对24个鉴定点进行分类;借助典型变量、判别分析及显著性检验进行品种鉴别.[结果]1)不同品种叶片形态差异主要受对称组分影响,在非对称组分中差异不明显.对称组分前2个主成分的累计贡献率为80.6％,可作为板栗品种差异分析的典型变量,对称组分的网格变化图显示品种间差异显著.2)主成分及异速生长分析显示,贡献率排名前14的鉴定点一致,可作为一级鉴定点.3)对称组分中前2个变量的累计贡献率为81.4％.散点图显示,除'怀九'与'燕丰','燕山红栗'与'燕昌','燕龙'与'燕明','六月爆'与'叶里藏'相似度较高,其余品种均能准确区分.4)产区间判别分析显示,除湖北与安徽(97.5％vs.96.9％),其余产区间的正确判别率均达到100.0％;品种间判别分析显示,有99.3％的品种间判别率达到100.0％,个别品种判别率较低且均为95.0％以上,判别结果均存在显著差异(P<0.05).5)聚类分析反映产区及品种间叶形的相似性,分类结果与种源地理分布基本吻合.[结论]基于24个鉴定点的几何形态测量分析可实现不同板栗品种的准确鉴别,筛选出的14个一级鉴定点,3个次级鉴定点,7个补充鉴定点,可准确反映不同板栗品种叶形的主要差异部位,正确判别率达95.3％～100.0％.建立的板栗品种叶形鉴别数据库和基于叶片形态数字化分析的板栗品种鉴别方法,将对板栗品种精准鉴别提供技术支撑.

[目的]通过比较分析不同品种板栗表型性状,筛选出表型差异较大且不易受环境影响的指标,以期为生产实践中板栗品种鉴别及实现精准应用提供参考.[方法]以来自我国不同板栗产区的80个品种,共3 200个坚果为试验材料,对其21个表型性状进行差异性、多样性分析;对表型与环境因子相关性进行分析,筛选出变异系数较小的稳定性指标;利用多地栽培的3个品种进行稳定性验证.[结果](1)不同地区板栗表型指标存在显著差异,湖北、江苏、安徽地区品种坚果、底座大小均显著高于其它地区.(2)21个表型指标变异范围为4.05％～42.28％,除去在群体内及群体间存在显著差异的指标,筛选出9个在品种间存在差异且变异系数较小的相对稳定指标,即果形指数、坚果圆度、底座圆度及相关比值指标.(3)相关性分析显示:坚果大小、底座大小相关指标与年平均温度、生长季平均温度、年降水量、生长季降水量均存在极显著正相关,与年日照时数、生长季日照时数均存在极显著负相关.(4)多地栽培的3个品种的9个坚果表型指标变异系数为1.13％～5.99％;方差分析结果显示,底座圆度在区域间差异显著,其余8个指标在区域间及个体间均差异不显著.[结论]不同板栗品种在21个坚果表型指标中具有丰富多样性及显著差异性,其中,果形指数、坚果圆度、底座长宽比、相对底座大小、底座弧长/坚果周长、底座面积/横切面积、底座长/横径、底座宽/厚度等8个坚果表型指标为稳定性指标,可应用于生产实践板栗品种鉴别.

[目的]探明板栗(Castanea mollissima)果实褐变度与总酚和总黄酮的相关性,基于此对板栗品种进行抗褐变评价,并筛选出抗褐变性较强的品种.[方法]以 105 个板栗品种为研究对象,利用分光测色计和紫外分光光度计,对烤制前后板栗仁褐变度、总酚和总黄酮含量及内果皮总酚和总黄酮含量进行测定,分析褐变度与总酚和总黄酮含量之间的关系,并采用熵权法和灰色关联度法对不同板栗品种进行抗褐变综合评价,获得不同板栗品种抗褐变性评价模型.[结果]栗仁烤制前后子叶表层、子叶心部和子叶中部褐变度值(△L)差异均较大,从大到小依次表现为板栗子叶表层＞子叶中层＞子叶心部.板栗内种皮总酚含量(544.46 mg/g)和总黄酮含量(484.25 mg/g)均显著高于栗仁;子叶表层褐变度与总酚含量呈极显著正相关(R=0.863),与总黄酮含量呈不显著正相关(R=0.445),总酚含量和总黄酮含量呈不显著正相关(R=0.411);权重系数最大的指标为褐变度(w= 0.5143).根据加权关联度可将105 个板栗品种划分为3 个等级,即抗褐变性极强,包括51 个品种,加权关联度为0.9206～0.9723;抗褐变性较强,包括 29 个品种,加权关联度为 0.8354～0.9098;抗褐变性弱,包括 25 个品种,加权关联度为0.7082～0.8267.[结论]板栗内果皮总酚含量与栗仁褐变密切相关,北方板栗抗褐变性强于南方,其中河北地区板栗品种'燕山早丰''东陵明珠''大板红'抗褐变性位居前三.

[目的]筛选影响板栗品质的关键气候因子,进行不同生态区域板栗气候适应性评价及其适宜性种植区划,为板栗引种以及科学种植提供理论依据.[方法]以我国不同生态区域(黄淮海、西北、长江中下游、西南等4大区域)105个板栗品种(含优系)为研究对象,对其坚果单粒质量、果形指数等表型性状和可溶性糖、淀粉、蛋白质等内在品质进行差异性分析,选择4大区域中24个板栗主栽区的12个气候因子进行主成分分析,筛选与板栗品质形成最密切的气候因子,通过逐步回归构建板栗气候品质评价模型;利用气候适应性指数(CAI)对板栗进行气候适应性评价和适宜性分区.[结果](1)不同生态区域板栗表型性状和内在品质均存在显著差异性.长江中下游地区单粒质量和果形指数均显著高于其他地区,黄淮海地区可溶性糖最高,支链淀粉/直链淀粉比值最大.(2)影响板栗坚果品质的主要气候因子为热量因子,其次为光照因子和水分因子.单粒质量与年平均温度和生长季降水量呈显著正相关,与生长季温差呈显著负相关;果形指数与年平均温度和生长季平均温度均呈显著负相关;含水量与生长季降水量呈极显著正相关;可溶性糖与生长季温差和生长季日照时数均呈极显著正相关,与生长季降水量呈不显著负相关;支链淀粉/直链淀粉比值与生长季平均温度和生长季温差均呈极显著正相关;蛋白质与年平均温度呈显著正相关,与年日照时数和生长季日照时数均呈负相关,与生长季降水量呈不显著负相关.(3)根据CAI,4大区域中24个板栗主栽区可划分为最适宜区、较适宜区和适宜区.黄淮海北部区域CAI值达到0.90～0.96,为最适宜区;黄淮海东部、西北和西南区域CAI值为0.81～0.89,属较适宜区;而长江中下游区域CAI值最低,为0.71～0.77,属适宜区.[结论]生长季温差大、平均温度高、日照时数长的气候条件有利于板栗坚果甜、糯品质的形成.

以河北迁西县8年生板栗'燕山早丰'(Castanea mollissima'Yanshanzaofeng')为研究对象,采用单因素随机区组试验设计,设置6个处理,100％无机肥(处理1)、75％无机肥质量+25％有机肥质量(处理2)、50％无机肥质量+50％有机肥质量(处理3)、25％无机肥质量+75％有机肥质量(处理4)、100％有机肥(处理5)、不施肥(对照),采用连续根钻法采集土层土样和根样,测定分析根际土壤及细根的碳、氮、磷等指标,并分析根际土壤及细根之间的关系.结果表明:有机-无机肥配施有效提高了细根和根际土壤的有机碳、全氮、全磷质量分数及碳氮摩尔质量比、碳磷摩尔质量比、氮磷摩尔质量比,各处理间差异显著(P<0.05).在0<h≤20 cm土层中,处理4与对照相比,土壤有机碳、全氮、全磷质量分数以及碳氮摩尔质量比分别显著提高18.60％、12.64％、14.71％、8.84％,土壤碳磷摩尔质量比提高了3.80％,细根的全氮、全磷质量分数分别提高了46.60％、43.75％,细根的氮磷摩尔质量比提高了1.79％;在20 cm<h≤40 cm土层,处理4与对照相比,土壤有机碳、全氮、全磷质量分数以及碳氮摩尔质量比分别显著提高了16.27％、10.84％、11.76％、5.01％,细根的全氮、全磷质量分数分别提高了51.63％、37.23％.处理4比对照的土壤碳磷摩尔质量比提高了3.80％,细根的氮磷摩尔质量比提高了9.83％.土壤有机碳、全磷质量分数与细根碳、氮、磷质量分数及氮磷摩尔质量比呈极显著正相关,与细根碳氮摩尔质量比、碳磷摩尔质量比呈极显著负相关.研究区域氮素为养分的限制因子,有机-无机肥合理配施可缓解氮素缺失,有效提高土壤有机碳、全氮、全磷质量分数,促进细根养分吸收,是河北迁西县板栗园施肥模式的较佳选择.

[目的]合理施肥与地表覆盖是干旱地区板栗高产优质的必要措施,本研究依据河北省迁西县当地实际情况提出一个优化的行间覆草和有机无机肥配施土壤管理模式,并进行效果验证,旨在为其改进和推广提供理论依据.[方法]以8年生板栗品种'燕山早丰'为研究对象,采用裂区试验设计,主处理为行间覆草(GC)和清耕(CT),副处理为4个施肥处理,即单施无机肥(F)、单施有机肥(M)、有机肥与无机肥配施(F+M)和不施肥(CK),于2019年和2020年连续两年研究覆草-施肥模式对板栗叶片功能性状与果实产量品质的影响,运用主成分分析法对各处理28项指标进行综合评价,筛选出最佳土壤管理模式.[结果](1)各施肥处理的新梢长度和粗度、叶面积、百叶干质量、百叶厚以及叶片矿质元素含量均有不同程度增加,且GC(F+M)处理显著高于其他处理.(2)地表覆草和不同施肥处理均可提高叶片叶绿素含量、光合速率和水分利用效率,增量最为明显的是GC(F+M)处理,分别比GC(CK)提高了6.00％、20.13％和44.87％.(3)有机无机肥配施(F+M)对于提高板栗坐果率、出实率、单粒质量和单株产优于单一施肥处理,其中GC(F+M)和CT(F+M)处理的单粒质量分别可达到10.32和9.92 g,较CT(CK)分别提高了26.01％和21.12％.(4)不同覆草-施肥模式处理的单株产量增幅为4.95％ ～45.21％,GC(F+M)处理的淀粉和可溶性糖含量较CT(CK)处理分别提高了13.04％和36.57％.(5)主成分分析结果表明,GC(F+M)处理综合得分最高,其次为GC(F)处理,然后是CT(F+M)和CT(F)处理,说明有机无机肥配施比单施无机肥更有利于板栗枝条和叶片的生长发育,以及光合性能和果实产量品质的提高.[结论]在迁西干旱地区板栗栽培中,地表覆草-有机无机肥配施模式是该地区板栗提质增产的最适土壤管理方式.

Dehydrins (DHNs) belong to group II of late embryogenesis-abundant (LEA) proteins, which are up-regulated in most plants during cold, drought, heat, or salinity stress. Despite the importance of dehydrins for the plants to resist abiotic stresses, it is necessary to obtain plant-derived dehydrins from different biomass. Generally, dehydrin PicW1 from Picea wilsonii is involved in Kn-type dehydrin with five K-segments, which has a variety of biological activities. In this work, Picea wilsonii dehydrin PicW1 was expressed in Escherichia coli and purified by chitin-affinity chromatography and size-exclusion chromatography, which showed as a single band by SDS-PAGE. A cold-sensitive enzyme of lactate dehydrogenase (LDH) is used to explore the protective activities of other proteins. Temperature stress assays showed that PicW1 had an effective protective effect on LDH activity, which was better than that of bovine serum albumin (BSA). This study provides insights into the purification and protective activity of K5 DHNs for the advancement of dehydrin structure and function from biomass.

[目的]为解决河北迁西地区板栗园干旱缺水和不合理施肥导致的土壤肥力下降等问题,依据当地实际情况提出一个优化的土壤管理模式,并进行效果验证,为其改进和推广提供理论依据.[方法]以8年生板栗燕山早丰(Casta-nea mollissima'Yanshanzaofeng')为研究对象,采用裂区试验设计,主处理为行间覆草(GC)和清耕(CT),副处理为4个施肥处理,即无机肥(F)、有机肥(M)、有机肥和无机肥配施(F+M)、不施肥(CK),于2019和2020年连续2a(年)研究覆草-施肥模式对板栗园土壤状况和细根形态以及单株产量的影响.[结果]行间覆草处理的土壤平均含水量显著高于清耕处理,覆草区0～20 cm和20～40 cm土层平均含水量分别比清耕区相应土层高18.76％、17.62％;而且行间覆草还具有高温时节降温、低温时节保温的作用;各施肥处理均能降低0～40 cm土层的土壤容重,增加总孔隙度.覆草和施肥处理可显著提高板栗园根际土壤有机质和速效养分含量,对板栗细根养分含量和形态特征也产生了显著的影响,而且各指标均表现为GC＞CT,其中GC(F+M)和CT(F+M)处理的增量最为显著;GC(F+M)处理的单株产量最高,不同覆草-施肥模式增产幅度为4.95％～45.21％.聚合增强树分析表明,不同土壤理化指标对板栗单株产量的贡献程度由大到小依次为AN＞AK＞AP＞SWC＞TEM＞OM＞pH＞TP＞ SBD,土壤速效养分和含水量对单株产量的贡献率最高,分别为52.21％、13.91％.[结论]在迁西地区板栗栽培中,行间覆草结合有机肥和无机肥配施是该地区板栗增产的较适宜的土壤管理方式,建议广泛推广.

[目的]板栗是我国大力发展的木本粮食树种,结合无机肥速效性与有机肥持久性的有机-无机肥配合施用,对培肥土壤、促进根系生长能起到重要作用.探讨有机-无机肥配施对板栗园土壤肥力及其根系功能性状的影响,以期为板栗的科学合理施肥提供依据.[方法]以河北迁西县8年生板栗'燕山早丰'(Castanea mollissima'Yanshanzaofeng')为对象,采用单因素随机区组试验设计,按质量占比设置6个处理:①100％无机肥(C1),②75％无机肥+25％有机肥(C0.75 O0.25),③50％无机肥+50％有机肥(C0.5 O0.5),④25％无机肥+75％有机肥(C0.25 O0.75),⑤100％有机肥(O1),⑥不施肥(CK),采用连续根钻法采集0～20、≥20～40 cm土层土样和根样,测定分析土壤理化性状及根系功能性状等指标.[结果]①各处理不同程度地影响土壤理化性状.O1处理0～40 cm土层平均有机碳含量最高(5.97 g/kg),0～20 cm土层C1处理全氮含量最大(1.33 g/kg),但以有机-无机肥配施C0.25 O0.75处理对土壤理化性状改善具有显著促进作用(P<0.05).C0.25 O0.75处理0～40 cm土层平均土壤C/N值较C1和CK处理的分别提高38.81％、11.41％;与CK相比,平均碱解氮含量、有效磷含量、速效钾含量分别增加57.48％、47.49％、32.19％;土壤总孔隙度、土壤含水率分别增加11.23％、13.85％;土壤容重降低11.23％.②有机-无机肥配施显著促进0～40 cm土层中平均细根根长密度、细根表面积密度、细根体积密度、比根长(P<0.05),且0～1 mm细根增多,各处理大小总体表现为C0.25 O0.75>C0.5 O0.5>C0.75 O0.25,以C0.25 O0.75处理0～40 cm土层中平均细根生物量密度最高(511.24 g/m3),较CK处理增加35.42％,较C1处理增加6.00％.高比例有机肥配施明显提高了细根根长、根表面积、根体积的占比.③主成分分析表明,土壤理化及根系性状指标在3个主成分上均有较高的荷载值,不同处理下土壤肥力与根系指标优劣综合排序为C0.25 O0.75>C0.5 O0.5>C0.75 O0.25>O1>C1>CK.[结论]有机-无机肥配施中的C0.25 O0.75处理有效提高了土壤C/N、速效养分含量,0～1 mm细根增多,提高吸收根比例,是河北迁西县板栗园的较佳施肥模式.

为了解迁西板栗"燕山早丰"叶片及土壤养分含量对产量的影响,通过路径分析和相关性分析对迁西县17个代表性"燕山早丰"板栗园土壤和叶片养分状况与产量进行分析,得出叶片不同养分元素以及土壤养分含量对板栗产量影响的直接作用和间接作用.结果显示,路径分析中残差值均小于0.4,即板栗叶片或土壤的养分元素含量对产量的影响权重均超过60％;高产果园中,提高板栗叶片N、P、Ca、Mn、Fe、Mg含量,提高土壤N、Fe、Mn含量均有利于提高板栗产量;低产果园中,提高板栗叶片N、Ca、Mg含量,提高土壤N含量均有利于提高板栗产量.因此,在高产果园中,向土壤中增施N、P、Fe、Mn等肥料,向叶面喷施Ca、Mg等叶面肥料均有利于提高板栗产量;低产果园中,向土壤中增施N肥和向叶面喷施Ca、Mg、Fe、Cu等元素叶面肥料是提高产量的有效措施.

[目的]探究叶幕微环境因子对板栗枝叶生长及果实产量的影响,为自然状态下果树的整形修剪及培养合理的枝叶群体结构提供理论依据.[方法]以30株8年生板栗树为研究对象,对东西南北4个方向条件下的上、中、下冠层,共16个区域进行温度、湿度及光强的测定,并测定每一区域内的枝条长度及粗度、叶SPAD及氮含量、果实单粒重,并将微环境因子与其进行相关性分析.[结果]温度及湿度在板栗冠层不同区域内无显著差异,光照强度在冠层各区域差异显著,南向平均光强最高,且同一冠层条件下,西向和北向的光强均小于东向和南向;板栗不同区域一年生枝条长度差异显著,但粗度无显著差异,北向下部枝长最短,东向上部枝长最长,且垂直条件下枝条平均长度随冠层高度的降低而减小;板栗树冠不同区域叶SPAD值、氮含量均差异显著,氮含量最高的区域为东向下部,最低为北向上部,且冠层上部氮含量最低;相关分析表明,微环境因子对不同方向间叶果生长指标的影响均不显著,但与不同区域、不同冠层多个生长指标呈显著相关关系,其中,温湿度与枝长、枝粗呈负相关,光照与果实产量、叶干质量均呈正相关,与叶含水率、叶氮含量呈负相关,且不同层次上的相关性均大于不同区域内;不同区域内SPAD值与光强相关性极弱,不同层次上SPAD值与光强呈极显著负相关.[结论]在冬季修剪的基础上,应对东、南方向的枝叶适当进行夏季修剪,以改善西、北方向冠内光照条件,使保证树体受光条件均匀;同时,应根据生产实际,对中上部的枝叶进行修剪,以增加下层透光率,提高叶片营养与果实产量.

Yield and quality of chestnut (Castanea mollissima Blume) are affected by nitrogen (N) availability; however, there are few reports on foliar and root absorption of different chemical forms of N in chestnut. To analyze the absorption characteristics of exogenous N fertilizer labeled by 15N in chestnut, nitrate and ammonium nitrogen uptake and allocation were determined in 1-yr-old seedlings that received soil and foliar 15NH4NO3 and NH415NO3. We found that 29% of the nitrate and 25% of the ammonium absorbed by the leaves were translocated to the roots, while 62.01% of the nitrate and 63.27% of the ammonium absorbed by the roots were translocated to the shoots. The seedlings absorbed more nitrate nitrogen than ammonium nitrogen, and their foliar N uptake was faster than their root uptake. Most of the N absorbed by the seedlings was fixed in the shoots in both foliar and soil uptake. The proportion of N fixed was greater in seedlings subjected to foliar fertilization than in those treated with soil fertilizer. Foliar fertilizer application can meet the N nutritional needs of fast-growing shoots more effectively than soil fertilizer application; however, soil fertilization was a better long-term N source than foliar fertilization. Thus, ensuring an adequate supply of nitrate N fertilizer in the soil accompanied by a commensurate increase in foliar fertilizer application can effectively meet the nutrient requirements associated with the rapid growth of chestnut seedling shoots.

Chinese chestnut ( Castanea mollissima Blume) seed kernels (CCSK) with high quality and quantity of starch has emerged as a potential raw material for food industry, but the molecular regulatory mechanism of starch accumulation in developing CCSK is still unclear. In this study, we firstly analyzed the fruit development, starch accumulation, and microscopic observation of dynamic accumulation of starch granules of developing CCSK from 10 days after flowering (DAF) to 100 DAF, of which six representative CCSK samples (50–100 DAF) were selected for transcriptome sequencing analysis. Approximately 40 million valid reads were obtained, with an average length of 124.95 bp, which were searched against a reference genome, returning 38,146 unigenes (mean size = 1164.19 bp). Using the DESeq method, 1968, 1573, 1187, 1274, and 1494 differentially expressed unigenes were identified at 60:50, 70:60, 80:70, 90:80 and 100:90 DAF, respectively. The relationship between the unigene transcriptional profiles and starch dynamic patterns in developing CCSK was comparatively analyzed, and the specific unigenes encoding for metabolic enzymes (SUSY2, PGM, PGI, GPT, NTT, AGP3, AGP2, GBSS1, SS1, SBE1, SBE2.1, SBE2.2, ISA1, ISA2, ISA3, and PHO) were characterized to be involved potentially in the biosynthesis of G-1-P, ADPG, and starch. Finally, the temporal transcript profiles of genes encoding key enzymes ( susy2 , pgi2 , gpt1 , agp2 , agp3 , gbss1 , ss1, sbe1, sbe2.1, sbe2.2, isa1, isa2, isa3 , and pho ) were validated by quantitative real-time PCR (qRT-PCR). Our findings could help to reveal the molecular regulatory mechanism of starch accumulation in developing CCSK and may also provide potential candidate genes for increasing starch content in Chinese chestnut or other starchy crops.

试验于2019年在河北迁西地区展开,以8 a生板栗品种'燕山早丰'(Castanea mollissima'Yanshanza-ofeng')为研究对象,采用随机区组设计,在种植行间利用杂草、黑膜进行覆盖,共设置(Ⅰ)清耕(CK);(Ⅱ)覆膜;(Ⅲ)覆草;(Ⅳ)覆草+覆膜4个处理,研究行间覆盖对板栗园土壤理化性质、光合特性以及叶片生长发育和果实产量品质的影响,并从经济效益方面进行了分析比较.结果表明:行间覆草处理可以明显使土壤温度日较差变小,在0～20cm土层,夏季(6月30日)不同处理的温差日变化范围为Ⅱ(3.65℃)>Ⅰ(2.82℃)>Ⅲ(1.73℃)>Ⅳ(1.62℃),秋季(10月30日)不同处理的温差日变化范围为Ⅱ(2.14℃)>Ⅰ(2.01℃)>Ⅲ(1.78℃)>Ⅳ(1.69℃);对于20～40 cm土层的土壤温度日变化与0～20 cm土温变化趋势一致,但是没有明显的峰值,波动范围在0.5℃左右.在生长期内(4—10月),覆膜、覆草、覆草+覆膜处理的平均土壤含水量分别比CK高1.78％、3.34％和5.11％,可见覆草+覆膜处理的蓄水保湿效果最为显著,其贮水量在生育期末较生育期初增加39.56 mm,且土壤水分利用效率可达2.25 kg·hm-2·mm-1.不同覆盖处理均能显著降低0～20 cm土层的土壤容重,增加土壤总孔隙度,变化幅度为2％～8％,提高板栗园土壤有机质和速效养分含量,均以覆草和覆草+覆膜处理效果较好.而且覆草+覆膜处理可显著增加百叶干质量、叶面积和比叶质量,分别比CK高9.61％、2.39％、7.05％.覆草和覆草+覆膜处理下板栗叶片的水分利用效率(2.67μmol·mmol-1和3.01μmol·mmol-1)显著高于CK(2.10μmol·mmol-1),SPAD值分别比CK高4.62％和6.95％.杂草覆盖可以提高板栗单粒重、坐果率和出实率,降低空苞率,进而增加产量,其中覆草和覆草+覆膜处理的坐果率较大,分别可达75.68％、79.48％,其产量分别比CK高10.07％、15.00％,而且杂草覆盖还能有效改善板栗果实品质.从经济学角度分析,覆草处理的净收益(13052.80元·hm-2)和产投比(5.08)最高,经济效益最大,可以在干旱半干旱山区板栗园应用.

[目的]研究板栗胚轴的临界含水量,探索板栗种子低温保存技术和胚轴超低温保存技术,为板栗等顽拗性种子设施保存提供参考.[方法]以采自山东济南的‘烟泉’品种板栗种子为试验材料,剥取其胚轴,使用硅胶快速脱水至目的含水量,测定不同含水量胚轴的萌发率.基于差示扫描量热技术(DSC),分析不同含水量胚轴的热力学特征,根据胚轴含水量和对应热焓关系测算胚轴临界含水量.运用低温密封保存法保存板栗种子,采用直接冷冻法、程序冷冻法、玻璃化冷冻法和程序玻璃化冷冻法对不同含水量板栗胚轴进行超低温保存测定.[结果]1)含水量从初始的61％降至25％时,胚轴萌发率未明显下降;当含水量降至20％时,萌发率降至82.1％;当含水量降至10％,萌发率降至25.6％.2)DSC热分析显示,随着胚轴含水量降低,结晶起始温度、峰值温度和热焓均呈规律性下降趋势,二者显著正相关.当含水量降至25％时,结晶起始温度降至-37.2℃,峰值温度降为-44.1℃,热焓值降为5.0J· g-1 dw;当含水量降至20％时,冷却结晶和加热熔融阶段均无结晶峰出现.3)以胚轴含水量和对应热焓测算,‘烟泉’品种板栗胚轴的萌发率开始显著下降的脱水临界含水量为23.9％.4)将板栗种子密封保存在2℃低温环境下6个月,种子萌发率、胚根和胚芽长度无显著性变化(P＞0.9).5)在4种超低温保存方法中,程序玻璃化冷冻法和玻璃化冷冻法的胚轴萌发率高于直接冷冻法和程序冷冻法,程序玻璃化冷冻法效果最好.[结论]板栗胚轴含水量降至20％及以下会对胚轴萌发活力产生影响,属于典型顽拗性种子.基于差示扫描量热技术,结合不同含水量胚轴萌发情况,可有效确定板栗等顽拗性种子的临界含水量,‘烟泉’品种板栗胚轴的临界含水量为23.9％.板栗种子在2℃低温密封保存条件下可有效保存6个月以上,其萌发率、根胚胚芽长度无显著变化.加入冷冻保护剂PVS2可提高板栗胚轴超低温保存后的萌发率.

[目的]冠层是林木与外部环境相互作用的重要部分,研究板栗树冠不同部位光合作用的空间变化规律,为揭示植物冠层生产力提供理论依据.[方法]以8年生板栗树为试验材料,采用Li-6400便携式光合作用测量系统,于7月对板栗树冠不同冠层和不同方位进行光合日变化测定,并取光合参数的日均值进行方差分析及通径分析,于9月对不同冠层和不同方位的刺苞进行采集,测定坚果经济性状,并进行方差分析及相关性分析.[结果](1)东上、东中、南中及南下冠层的净光合速率日变化呈单峰曲线分布,其余部位均表现为双峰曲线,呈双峰曲线分布的区域均于13:00出现"午休"现象;每一冠层区域的水分利用效率日动态均呈双峰曲线.(2)在冠层垂直方向上,水汽压亏缺及胞间CO2浓度均呈"下部>中部>上部"的规律,其最大值分别为2.13 kPa、274.93μmol/mol,最小值分别为1.95 kPa、258.75μmol/mol;光合速率、气孔导度、蒸腾速率、光合有效辐射、水分利用效率及羧化效率均呈"上部>中部>下部"的规律,同时,相对叶绿素含量(SPAD)和比叶面积(SLA)在垂直冠层上均有显著差异,表现为"下层>中层>上层"的规律.(3)在树冠不同方位,东面光合能力最强,各冠层光合生理生态指标有一定差异性,但无垂直方向差异显著;SLA在不同方位无显著差异,仅SPAD在东西向与北向差异显著.(4)通径分析得出,影响板栗净光合速率的主要因子为蒸腾速率、水分利用效率、羧化效率、水汽压亏缺、气孔导度、气温及胞间CO2浓度,其中,只有气温对净光合速率起抑制作用,蒸腾速率是对板栗光合作用影响最大的生理因子,水汽压亏缺是对板栗光合作用影响最大的环境因子.(5)垂直冠层上,净光合速率与单粒质量、出实率和单位面积产量均呈显著或极显著正相关,相关系数分别为0.872、0.965、0.958;水平冠层上,净光合速率与单粒质量、单位面积产量呈显著正相关,相关系数分别为0.777、0.487;对水平和垂直冠层进行综合分析发现,净光合速率与单粒质量、出实率、单位面积产量均呈显著或极显著正相关关系,相关系数分别为0.600、0.669与0.532.[结论]板栗光合具有明显的空间异质性,各光合指标与果实产量的差异性是垂直冠层和水平冠层综合作用的结果.因此,在估算冠层生产力时,应充分考虑到冠层光合作用的垂直变化和水平变化,在实际生产中,应合理修枝,提高冠层中下部的光能利用率,从而促进果实产量的提高.