Linking leaf elemental traits to biomass across forest biomes in the Himalayas

Plants require a number of essential elements in different proportions for ensuring their growth and development.The elemental concentrations in leaves reflect the functions and adaptations of plants under specific environmental conditions.However,less is known about how the spectrum of leaf elements associated with resource acquisition,photosynthesis and growth regulates forest biomass along broad elevational gradients.We examined the influence of leaf element distribution and diversity on forest biomass by analyzing ten elements(C,N,P,K,Ca,Mg,Zn,Fe,Cu,and Mn)in tree communities situated every 100 meters along an extensive elevation gradient,ranging from the tropical forest(80 meters above sea level)to the alpine treeline(4200 meters above sea level)in the Kangchenjunga Landscape in eastern Nepal Himalayas.We calculated communityweighted averages(reflecting dominant traits governing biomass,i.e.,mass-ratio effect)and functional divergence(reflecting increased trait variety,i.e.,complementarity effect)for leaf elements in a total of 1,859 trees representing 116 species.An increasing mass-ratio effect and decreasing complementarity in leaf elements enhance forest biomass accumulation.A combination of elements together with elevation explains biomass(52.2%of the variance)better than individual elemental trait diversity(0.05%to 21%of the variance).Elevation modulates trait diversity among plant species in biomass accumulation.Complementarity promotes biomass at lower elevations,but reduces biomass at higher elevations,demonstrating an interaction between elevation and complementarity.The interaction between elevation and mass-ratio effect produces heterogeneous effects on biomass along the elevation gradient.Our research indicates that biomass accumulation can be disproportionately affected by elevation due to interactions among trait diversities across vegetation zones.While higher trait variation enhances the adaptation of species to environmental changes,it reduces biomass accumulation,especially at higher elevations.

Leaf stoichiometry of Leontopodium lentopodioides at high altitudes on the northeastern Qinghai-Tibetan Plateau,China

Altitude affects leaf stoichiometry by regulating temperature and precipitation,and influencing soil properties in mountain ecosystems.Leaf carbon concentration(C),leaf nitrogen concentration(N),leaf phosphorous concentration(P),and their stoichiometric ratios of Leontopodium lentopodioides(Willd.)Beauv.,a widespread species in degraded grasslands,were investigated to explore its response and adaptation strategy to environmental changes along four altitude gradients(2500,3000,3500,and 3800 m a.s.l.)on the northeastern Qinghai-Tibetan Plateau(QTP),China.The leaf C significantly varied but without any clear trend with increasing altitude.Leaf N showed an increasing trend,and leaf P showed a little change with increasing altitude,with a lower value of leaf P at 3500 m than those at other altitudes.Similarity,leaf C:P and N:P exhibited a little change with increasing altitude,which both had greater values at 3500 m than those at other altitudes.However,leaf C:N exhibited a decreasing trend with increasing altitude.Soil NH^(+)_(4)-N,soil pH,soil total phosphorus(STP),mean annual temperature(MAT),and mean annual precipitation(MAP)were identified as the main factors driving the variations in leaf stoichiometry of L.lentopodioides across all altitudes,with NH^(+)_(4)-N alone accounting for 50.8%of its total variation.Specifically,leaf C and N were mainly controlled by MAT,soil pH,and NH^(+)_(4)-N,while leaf P by MAP and STP.In the study area,it seems that the growth of L.lentopodioides may be mainly limited by STP.The results could help to strengthen our understanding of the plasticity of plant growth to environmental changes and provide new information on global grassland management and restoration.

Soil and Leaf Micronutrient Composition in Contrasting Habitats in Podzolized Sands of the Amazon Region

Plant macronutrient distribution in podzolized sands of the Amazon caatinga has received attention in several studies;however, the distribution of micronutrients has not been assessed. Soil micronutrient availability has been hypothesized to reflect contrasting habitat characteristics as well as fundamental differences in substrate, and leaf micronutrient composition may reflect the macronutrient content needed to maintain balance for leaf cell functions. In this study, soil and leaf samples were obtained in a toposequence (valley, slope, and mound). Available soil micro- and macronutrients as well as total leaf content were measured by inductively coupled plasma-atomic emission spectrometer and mass spectroscopy. Soil Zn (-1) and B (-1) as well as Cu (-1) levels were very low. Soil Mn was low in the valleys and slopes (0.62-0.87 mg·kg-1), but higher in the mound (6.59 mg·kg-1). Soil Fe (11.48-21.13 mg·kg-1) was well above the critical level in all of the habitats. Leaf micronutrients Cu, B, Zn, and Fe were below the critical levels for tropical crops of 3-7, 20-70, 15-20, and 72 mg·kg-1, respectively. Leaf Mn (88 mg·kg-1) and Al (<50 mg·kg-1) were below the accumulators level. A strong relationship between leaf micro- and macronutrients suggests the maintenance of a homeostatic elemental composition, which may favour photosynthetic function. Therefore, the local distribution of species may be shaped by their abilities to maintain a balance of micronutrient collected through roots under critically low levels of available Zn, B, and Cu whilst excluding potentially deleterious ions of Mn, Fe, and Al.

Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing

Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition. Fraxinus chiuensis, Sophora japonica Ailanthus altissima, Syringa oblata and Prunus persica, had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicns and Parthenocissus quinquefolia with low sampling height were 2-35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM30 （particulate matter less than 10 μm in aerodynamic diameter; 98.4%） and PM2.5 （particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%） which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO2, CaCO3, CaMg（CO3）2, NaCI and 2CASO4. H2O, SiO2. CaCO3 and CaMg（CO3）2 mainly came from resuspension of road dust. 2CaSO4. H2O was produced by the reaction between CaCO3 derived from earth dust or industrial emission and SO2, H2SO4 or sulfate. NaCl was derived from sea salt.

An Analysis on Leaf Traits of 22 Helianthus tuberosus Germplasm Resources Introduced from Abroad

Atomic absorption spectrophotometry,sulfuric acid and potassium dichromate oxidation method and ultraviolet spectrophotometry,were used to determine mineral elements,fiber,the content of chlorogenic acid and flavones in leaves of 24 Helianthus tuberosus Linn.resources,and the characteristics of the leaf introduced from abroad were evaluated.The results showed that the highest water content of 22 species was F12(27.58%),and the lowest was F16(19.02%).The difference in mean water content between the species from Denmark and France was small,but it was lower than that of Qingyu 3 and Qingyu 4.There were 3 orbicular leaves,1 long oval-shaped leaf and 18 oval leaves.The highest K content in the leaves was F19(30.62 mg/g),which was 2.5 times than Qingyu 3.The highest Mg content was D8(14.17 mg/g).The Fe content hadlittledifference,ranging from 0.09 mg/g to 0.19 mg/g.The highest Ca content was D8(26.87 mg/g).The highest level of chlorogenic acid and flavones was F7,2.55%and 1.24 g/100 g respectively.The highest fiber content was F9(16.7%),and the lowest was F19(7.36%).Through the analysis of the main component and the clustering analysis,when the genetic distance was 0.65,the 24 resources can be divided into three major categories.The first category of leaves were mainly oval and orbicular;the second category of leaves were long oval-shaped;the third category of leaves were oval.There was a difference between the various indexes in the leaf of different kinds of H.tuberosus Linn.resources.Finally,F19,D8,F9,F7,D14 and D11,6 specific species(F19,D8,F9,F7,D14 and D11)were screened out for further studies in the future.

Determination of Nutrient Contents in the Leaf Litter of <i>Diospyros crassiflora</i>S. (Hiern-FWTA) Plantation in Okwuta-Ibeku, Umuahia, Abia State, Nigeria

Determination of nutrient contents in Diospyros crassiflora leaf litter was carried out in the Forestry Research Institute of Nigeria (FRIN), Okwuta-Ibeku, Umuahia, Abia State, Nigeria in 2016 and 2017. Three 1 m × 1 m trays were randomly positioned for collection of leaf litter production from 4/5 years old Diospyros crassiflora species in each block (10 m × 25 m) within the plantation totaling 1.5 ha. A Randomised Complete Block Design (RCBD) with three replicates was used to study the mean monthly leaf litterfall of Diospyros crassiflora. Leaf litter was collected from each of the three litter trays per block and placed in paper bags every 28th day of each month from January-December in 2016 and in 2017. Fifteen grammes (15 g) of properly mixed and oven-dried samples of D. crassiflora leaf litter were milled and sieved in 1 mm sieve;0.3 g was used to determine nutrient elements and their concentrations. The data obtained from mineral nutrient contents of D. crassiflora leaf litter was analysed using analysis of variance. Result reveals the mean concentrations of nitrogen (1.41 and 1.41 mg·l-1), phosphorus (0.18 and 0.18 mg·l-1), potassium (0.68 and 0.68 mg·l-1), sodium (0.35 and 0.30 mg·l-1), calcium (1.57 and 1.56 mg·l-1), magnesium (0.32 and 0.31 mg·l-1), chlorine (0.25 and 0.24 mg·l-1), Organic carbon (0.03 and 0.03 mg·l-1) and Organic matter (1.17 and 1.18 mg·l-1) etc. in D. crassiflora leaf litter in January-December (2016 and 2017). The study shows almost uniform distribution of mineral elements concentrations in 2016 and 2017.

土壤养分含量对山药叶片黄化的影响

以山药品种“雅山药1号”为试材,采用方差分析和相关性分析方法,研究了土壤养分含量对山药叶片黄化的影响,以期为改善黄化山药基地生产现状提供参考依据。结果表明:随着山药叶片黄化程度加剧,土壤pH、交换性Ca含量逐渐升高,土壤鲜样含水量、碱解N、速效K、有效Fe、总Fe、有效Mn含量逐渐降低,土壤有机质、有效P含量总体显著降低,有效S含量仅2级黄化低于0级,土壤交换性Mg、有效Zn、有效B、HCO_(3)^(-)含量与0级差异不显著。相关性分析结果表明,土壤pH与交换性Ca含量呈显著正相关,且二者与土壤含水量、有机质含量、碱解N、有效P、速效K、有效Fe、总Fe、有效Mn含量呈显著或极显著负相关。该研究初步确定山药叶片黄化与土壤pH、Ca含量升高,土壤有机质、含水量、N、P、K、Fe、Mn含量降低有关。

Finite Element Analysis of Elastic Deformation in Blade Machining

In the process of milling the half-open impeller, the milling force ACTS on the half-open impeller will cause the machining deformation error of the half-open impeller. The impeller material studied in this paper is 7050-t7451 aluminum alloy, whose elastic modulus is 70.3 GPa, with low stiffness. Therefore, during milling, it is easy to cause elastic deformation of the cutter, thus causing machining errors and reducing machining surface quality. In addition, due to the low stiffness of blade surface, the deformation of blade surface is much larger than that of hub surface. Therefore, this paper only studies the deformation law of blade surface in the process of milling.

香榧种实生长早期枝叶和种实矿质元素质量分数及积累量动态分析

【目的】探究香榧Torreyagrandis‘Merrillii’种实早期生长阶段枝叶与种实矿质元素质量分数、积累量的关系,为科学施肥,提升香榧种仁品质及产量提供依据。【方法】选择浙江农林大学东湖校区(2+17)a香榧试验林(砧木为2年生,嫁接后生长了17 a),采集3月上旬至7月上旬当年生侧枝(含叶片)及2代种实,对枝叶、种实中氮、磷、钾、钙、镁、锌、锰、铜质量分数及积累量动态变化关系进行分析。【结果】香榧种实早期生长阶段,种实横纵径、单果干鲜质量及含水率在4月上旬前无明显变化,4月中旬至6月中旬均增长迅速,之后趋于平稳。4月中下旬至6月中旬,枝叶中氮、磷、钾的积累量下降,而种实中氮、磷积累量及钾质量分数持续上升,表明枝叶中的氮、磷、钾优先供应种实的生长,缓生期与花芽分化期种实对氮、磷、钾的需求量较小,速生期种实对氮、磷、钾需求增加,该现象随时间推移而增强;在时间尺度上,钙在枝叶中逐渐吸收、积累,种实中钙质量分数及积累量则呈显著、极显著降低;速生期后,种实中的镁积累量增高,枝叶中镁积累量及质量分数均随着种实的膨大而下降;香榧种实早期生长阶段枝叶中锌、铜积累量呈下降趋势,种实对锌、铜、锰需求量较小。【结论】①速生期香榧种实的体积和含水率快速增加,进入充实期后趋于稳定。②元素质量分数、积累量与香榧种实生长期密切相关。为提高香榧种实品质,应在种实缓生期末期和速生期开始时施加氮、磷、钾肥,并配合施用适量锌、铜等微量元素肥料,在种实采收后施用镁肥。图5参27.

基于“三教”改革的职业教育活页式教材开发研究

校企“双元”协作开发活页式教材是职业院校深化“三教”改革急需解决的问题。通过对职业教育活页式教材形态、编写机制、内容组织模式、育人模式及教学模式变革的分析与归纳,提出活页式教材正朝着形态“活”、教师“活”、内容“活”、思想“活”、教法“活”的方向发展。在对“活页式”教材实践探索的基础上,设计职业教育活页式教材开发流程,构建融“三教”为一体的活页式教材建设框架,提出活页式教材体例格式,详解案例活页内容。

信阳文化元素在茶叶包装设计中的应用研究

文章旨在深入研究茶叶包装设计,聚焦于信阳文化元素在其中的创新性应用。通过对信阳文化独特元素的深入分析与巧妙结合,提升包装的文化价值与市场吸引力。茶叶包装在某些方面的缺失和不足已成为市场竞争中的短板。因此,文章首先核心聚焦于以茶叶包装为核心融入本土文化特色,并总结包装中存在缺乏地域性、缺乏创新性、缺乏环保性的问题。其次,从三个不同方面探讨将信阳文化元素在茶叶包装设计中的应用价值。最后,提取信阳文化元素来展开设计实践。以期在实际应用中,通过视觉设计赋能产品,提升茶叶的品牌价值,为地域性产品包装设计提供新思路。

无患子媛华不同物候期养分需求特征研究

为了解无患子媛华无性系原料林叶片矿质元素在不同关键物候期动态变化规律,揭示该无性系养分需求特征,为科学制定营养管理制度提供理论依据。以福建省建宁县树龄5、6、7 a的无患子媛华无性系原料林为研究对象,测定展叶期、花序抽生末期、花期末、果实膨大初期、果实转色期、果实成熟期N、P、K、Ca、S、Mg、Fe、Zn、B等含量指标。无患子媛华无性系原料林不同关键物候期叶片中N、P、K、Ca、Mg含量总体呈先降低、再上升、后降低趋势,均在果实膨大初期达到最高;N和P的含量在花序抽生末期和果实膨大初期之间存在显著差异,其K含量在果实膨大初期显著高于其他关键生育期,且在其余生育期之间无显著差异,而Ca含量和Mg含量在展叶期和果实膨大初期存在显著差异(P<0.05),Fe、B含量呈先上升后降低趋势,Fe含量在果实转色期显著高于其余生育期,B含量在花期末急剧降低,且显著低于其余生育期(P<0.05),Zn含量和S含量全年总体无明显变化。3个树龄叶片中N含量和K、P、Mg含量分别呈显著正相关,Ca含量和K、Fe含量分别呈显著正相关,S含量和Zn含量呈显著负相关,Zn含量和S、B含量分别呈显著负相关。坐果期(6—7月底)可作为叶片营养诊断的适宜时期;施肥应考虑各元素间的关联;在花序抽生末期时,此时应及早追施N、P和B肥;在坐果期要适量追肥,同时结合追施微肥。

动物源营养液对卷叶霸王空气凤梨新叶生长及矿质元素含量影响

为分析动物源营养液在空气凤梨上的应用效果,以‘卷叶霸王’空气凤梨为研究对象,以清水作对照,研究动物源营养液、磷酸二氢钾、尿素喷施后对空气凤梨新叶生长、单株增重、光泽度及矿质元素含量等的影响。结果表明,动物源营养液中含有钙、镁、铁、锌、硼和锰等矿质元素,空气凤梨在各种处理后3月内都没有新根萌出,均未出现肥害与微量元素中毒现象,光泽度没有明显差异。2.50‰营养液处理的第1小叶生长率增加41.58%,增加幅度最大。0.10‰动物源营养液处理单株增重率最高,2.50‰、0.50‰营养液处理次之;不同浓度动物源营养液处理间单株增重率差异不显著。与CK相比,3.33‰营养液处理、1.00‰营养液处理显著增加空气凤梨新叶内钙、镁、铁和锰含量,3.33‰动物源营养液处理的钙含量增加27.80%,镁含量增加23.71%,铁含量增加10.75%,锰含量增加104.41%。3.33‰营养液处理新叶内钙、镁、锰和硼含量显著高于1.00‰营养液处理,但铁和锌含量显著低于1.00‰营养液处理,生产上可以将动物源营养液作为卷叶霸王空气凤梨新型叶面营养肥进行合理开发与利用。

基于缺铁诊断指标筛选的猕猴桃叶片黄化诱因分析

[目的]筛选适宜的缺铁诊断指标,据此分析导致陕西关中地区猕猴桃园叶片黄化的主要因子,并利用施肥矫治试验对该因子进行验证,为猕猴桃叶片黄化防控提供理论依据。[方法]在陕西关中地区,依据叶片黄化后土施Fe-EDDHA可以复绿确定了3个缺铁猕猴桃果园,采集当年强旺营养枝顶端第2~3个叶片,共采集不同黄化度叶片64份,缺铁叶片样品的黄化度以SPAD值表征,将SPAD值与5个缺铁诊断指标进行相关分析。在关中地区选择5个健康果园、80个出现不同程度黄化症状的猕猴桃果园,采集叶片样品,将黄化果园叶片按照黄化程度分为绿叶、轻度黄化叶和重度黄化叶,测定12种元素、活性铁和硝态氮含量及SPAD值,并将其与SPAD值进行相关分析。在85个果园各采集1份土壤样品,分析其基础理化性状。选择两个黄化果园进行施肥矫治效果验证。[结果]64份缺铁黄化叶片中,鲜样邻二氮菲浸提铁与其SPAD值的相关性明显高于干样全铁、0.1 mol/L盐酸浸提铁、1 mol/L盐酸浸提铁和鲜样1 mol/L盐酸浸提铁,说明鲜样邻二氮菲浸提铁最适于猕猴桃缺铁的黄化诊断。健康园绿叶和黄化园绿叶中所测的12种元素、活性铁和硝态氮含量均无显著差异。SPAD和邻二氮菲浸提铁含量的顺序为黄化园绿叶>轻度黄化叶>重度黄化叶,而叶片硝态氮、磷、钾和硼含量则相反。轻度和重度黄化叶钙、全铁和锰含量低于绿叶。相关分析表明,猕猴桃叶片SPAD与叶片邻二氮菲浸提铁、全铁、锰和钙含量正相关,而与叶片钾、磷、硝态氮、全氮、硼、铜等含量负相关。随机森林和通径分析进一步表明,与猕猴桃叶片黄化关系最密切的指标为邻二氮菲浸提铁、钾及硝态氮。线性加平台函数拟合表明,邻二氮菲浸提铁5.084 mg/kg是猕猴桃叶片缺铁黄化诊断的临界值。土壤分析结果表明,黄化园土壤pH和碳酸氢根含量均偏高,而速效钾和硝态氮含量均适宜,说明土壤重碳酸盐诱发缺铁很可能是导致叶片黄化的主要原因。与健康园相比,黄化园土壤阳离子交换量偏低,说明叶片黄化还与土壤阳离子交换能力不足有关。施用Fe-EDDHA和蓝铁矿[Fe_(3)(PO_(4))_(2)·8H_(2)O]均可提高叶片SPAD和邻二氮菲浸提铁含量,降低叶片钾和硝态氮含量,从而矫治猕猴桃叶片缺铁黄化。[结论]叶片鲜样中邻二氮菲铁最适于猕猴桃缺铁黄化诊断,其临界浓度为5.084 mg/kg。陕西关中地区猕猴桃园叶片黄化主要是由土壤重碳酸盐诱发缺铁所致,且与土壤阳离子交换能力不足有关;黄化叶中钾和硝态氮的累积是由缺铁造成的。因此,生产上应注意黄化园铁肥的补充和土壤阳离子交换能力的提升。

拉力式甘蔗剥叶机剥叶元件作业参数研究

拉力式甘蔗剥叶机剥叶元件合理的作业参数可有效改善剥叶机构剥叶质量,为降低含杂率,建立甘蔗剥叶过程仿真模型,采用单因素仿真试验分析剥叶辊筒转速、剥叶角度及剥叶辊筒中心距(剥叶元件交错深度)对蔗叶所受峰值应力的影响规律和蔗叶的剥离断裂情况,确定参数范围;在仿真分析基础上采用中心组合法进行多因素样机试验,探究3个作业参数对含杂率的影响规律并得出最佳作业参数:剥叶角度120°、剥叶辊筒中心距77.2 mm、剥叶辊筒转速128 r/min、最小含杂率为2.03%,样机试验验证所得含杂率结果为2.09%。为改善拉力式甘蔗剥叶机剥叶效果、提高作业适应性提供参考。

不同海拔的大别山山核桃林地土壤性质和叶片营养元素分析

为了比较不同海拔大别山山核桃林地土壤性质和叶片营养元素的差异及相关性,为大别山山核桃林地科学施肥和养分管理提供参考,采用酸度计法、重铬酸钾容量法、半微量凯氏定氮法、碱解扩散法、盐酸氟化铵浸提-分光光度法和醋酸铵-火焰光度计法分别测定了不同海拔大别山山核桃林地0~30 cm土层p H、有机质、速效氮、速效磷、速效钾,采用原子吸收分光光度法测定了土壤和叶片的氮、磷、钾、钙、镁、锌含量,并进行显著性分析和相关性分析。结果表明:(1)不同海拔大别山山核桃林地土壤速效磷、全氮、全磷、全钾、钙、镁和锌含量存在显著性差异(P<0.05),大别山山核桃叶片钾、钙和镁含量存在显著性差异(P<0.05)。(2)不同海拔大别山山核桃林地土壤p H随着海拔升高而降低,而有机质和氮含量随着海拔升高而升高;叶片钾含量随海拔升高而升高,钙和镁含量则是随着海拔升高而降低,其余营养元素受海拔影响较小。(3)大别山山核桃叶片营养元素之间、土壤营养元素之间、以及叶片与土壤之间存在一定相关性,其中土壤间相关性达到显著水平的有2对,叶片间相关性达到显著水平的有4对,土壤和叶片间相关性达到显著水平的有2对(P<0.05)。大别山山核桃林地土壤平均p H值为5.18,偏酸性;有机质含量均值为5.07%;速效氮、速效磷含量较高,速效钾较匮乏;微量元素平均含量依次为Mg>Ca>Zn。建议增施生石灰进行土壤改良,减少氮肥施用,增施磷钾肥,尤其是钾肥,将化学肥料和有机肥料混合增施,保持土壤养分平衡。

烟草薄片剪切断面形貌有限元仿真模拟优化

本研究对烟草薄片精密剪切过程进行了仿真研究,获得了材料力学性能和相互作用参数,为有限元仿真模拟提供了必要数据。建立了烟草薄片的力学模型,并构建了相应的有限元仿真模型。在仿真模拟过程中,重点分析了烟草薄片剪切断裂的形成过程及静水应力随时间的变化趋势。采用有限元仿真模拟与实验测量相结合的方法,综合分析剪切间隙对烟草薄片断面质量的影响。结果表明,随着剪切纵向间隙的增加,烟草薄片的塌角高度逐渐增加,剪切带高度总体呈现减小趋势,而断裂带高度则呈现增加趋势。然而,当剪切间隙为0.15 mm时,由于上、下剪刃的重合,导致剪切带高度略微增加,断裂带高度略微减小。有限元仿真模拟结果与实测结果相吻合,验证了本研究的可靠性和准确性。

采前柰李果肉褐化现象与果园土壤营养因子、叶片元素含量的相关性分析

为研究柰李果肉褐化发生与发展机理,分析褐化现象发生与果实成熟期微环境以及果园土壤营养元素、叶片元素的相关性。以广东省乐昌市15个果园为试验园,采集柰李果实并按照褐变情况分类,对果园的土壤营养因子含量、叶片元素含量进行测定,并使用软件对数据进行统计和分析。结果显示,成熟期套袋柰李果肉褐化率显著增加,且果袋越厚发生褐化现象越严重;同时低海拔果园柰李果肉褐化率较高。相较于高褐化率(>20%)的果园,低褐化率果园土壤条件更优渥,如有机质含量、大量元素、中微量元素均显著较高。相关性分析显示,柰李果肉褐化率与土壤pH、速效磷、镁元素、铁元素、铜元素以及叶片镁元素呈正相关,与土壤有机质、钙元素、锌元素、锰元素、硼元素呈负相关。因此,降低果实成熟过程中果园环境温度,提升土壤pH、有机质、钙、硼等元素的含量,可能有助于降低果肉褐化率。

叶面喷施微生物制剂对苹果树体生长、果实表型性状和叶片营养元素的影响

为了分析叶面喷施微生物制剂对苹果树体生长、苹果果实表型性状和叶片营养元素的影响,设置了3种常用微生物制剂(T_(1):巨大芽孢杆菌菌剂、T_(2):枯草芽孢杆菌剂、T_(3):密旋链霉菌剂),分别按照不同剂量(10、20、30 g/667 m^(2))进行叶面喷施,对比分析了不同微生物制剂在不同施用剂量下对苹果生长、果实及营养指标的影响。结果表明:当T_(1)微生物菌剂的施用剂量为20 g/667 m^(2)时,苹果树冠径、干径、新梢长度、新梢粗度、百叶鲜重、百叶干重等树体的生长情况最佳;当T_(1)微生物制剂的施用剂量为20、30 g/667 m^(2)时,苹果果实单果重、果实横径、果实纵径、果柄粗度等表型性状指标较高,而果柄长度较低;T_(1)、T_(3)微生物制剂的施用剂量为30 g/667 m^(2)时,苹果叶片中的N、P、K含量均较高,且前者的Ca和Mg含量更高;T_(2)微生物制剂在果树树体生长、果实表型性状和叶片营养元素含量方面均低于T_(1)、T_(3)微生物制剂。综上,巨大芽孢杆菌菌剂的施用效果在3种微生物菌剂中最为理想,最佳施用剂量为20 g/667 m^(2)。

井冈蜜柚叶片营养诊断研究初报

以吉安地区井冈蜜柚有代表性的97个柚园为研究对象,通过测定井冈蜜柚叶片中营养元素N、P、K、Ca、Mg、Zn、Fe、Mn、Po、S的含量,运用诊断施肥综合法(DRIS)对叶片营养状况进行了分析。结果表明:依据高品质园蜜柚叶片矿质营养元素的含量范围,确定井冈蜜柚叶片矿质营养元素N、P、K、Ca、Mg含量的最适范围分别为23.15~25.86、1.89~2.56、12.06~15.24、40.65~61.45、1.85~2.00 g/kg;Zn、Fe、Mn、Po、S含量的最适范围分别为20.13~32.30、124.04~178.98、88.87~147.56、86.39~143.25、1.19~1.59 mg/kg。吉安市果园蜜柚叶片总体上需肥顺序由大到小为Mn>Po>Zn>Fe>Ca>Mg>N>S>P>K,其中井冈蜜柚园相对缺乏微量元素,低品质园则尤其突出,因此,应该采取具有区域针对性的施肥管理策略,并提出了相应的营养诊断标准。