Response of mango tree nutritional status and biochemical constituents to boron and nitrogen fertilization

Abstract

A field experiment was conducted at Al Malak Valley Farm, El-Sharkeya Governorate-Egypt (30°–51° N; 32°–53° E) using 15 years old productive mango (Mangifera indica L.) trees cv. Zebda. The experiment was repeated for two successive seasons (2014/2015) and (2015/2016). The trees were planted 8×8 meters apart in sandy soil under drip irrigation system using the Nile water. Treatments included three concentrations of boron (0.0, 250, 500?mg L^?1) and three concentrations of nitrogen (1000, 1250, 1500?g nitrogen/tree/year). Boron was applied as foliar spray of boric acid and nitrogen was applied to the soil as ammonium sulfate. Treatments were arranged in a factorial Completely Randomized Block Design with three replicates for each treatment. Results show that boron application has improved mango tree nutritional status. Leaf nitrogen, phosphorus, potassium and boron concentrations significantly increased as the boron application rate increased. In addition, boron application resulted in significant increase in leaf total chlorophyll, total carbohydrates, total sugars, carbon/nitrogen (C/N) ratio and decrease in total phenol content. Boron showed higher impact than nitrogen on all tested parameters. The interaction treatment of 250?mg L^?1 boron and 1500?g/tree nitrogen proved to be the best treatment.     

Diurnal variations in uptake,transport and assimilation of NO3 ‐and efflux of OH‐ in maize plants

Maize plants, grown for 7 and 21 days on a nutrient solution with NO₃ ^‐ as the sole nitrogen source showed a clear diurnal pattern with respect to the in vivo NRA. Especially in roots dark/light fluctuations of the enzyme activity were high. Also in NO₃ ^‐ uptake, OH^‐ efflux and endogenous content of water soluble carbohydrates a diurnal variation was found. The plant age did not significantly affect the daily rhythm.

Because day/night changes of the in vivo root NRA and nitrate uptake were proportional, the relative content of reduced N in the xylem sap of the plants was constant during a day/night interval. At both day 7 and day 21 about 40–50% of the N was transported via the xylem as amino N. As a result of non‐synchronous variation of the specific root and shoot NRA, root reduction capacity showed a great within‐day variation. It varied between 20 and 40% of the whole plant reduction capacity. Since the ratio N‐organic to N‐total in the xylem sap was about 0.5, cycling of organic nitrogen was very likely in these maize plants.     

日粮可降解蛋白与非纤维性碳水化合物对人工瘤胃发酵、 微生物合成以及纤维分解菌菌群的影响

【目的】探讨瘤胃降解蛋白（rumen degradable protein,RDP）水平和非纤维性碳水化合物（non-fibre carbohydrates,NFC）类型对人工瘤胃发酵、微生物合成和纤维分解菌菌群的影响。【方法】采用2×4双因素试验设计,即2种RDP水平和4种NFC类型（玉米淀粉、蔗糖、柑橘果胶和菊粉）。RDP水平通过向4种日粮中分别添加0（低RDP）或1.56 g（高RDP）酪蛋白酸钠调节。【结果】①主效应上,蔗糖和果胶组的干物质和有机物质表观消失率显著高于其它两组（P＜0.01）;日粮RDP水平和NFC来源在影响中性洗涤纤维的表观消失率上存在交互作用（P＜0.01）,低RDP水平的蔗糖（P=0.10）和果胶组（P=0.09）趋向于低于淀粉组,但高RDP水平的处理组间差异不显著;②主效应上,果胶组中白色瘤胃球菌（Ruminococcus albus）的16S rDNA拷贝数高于淀粉组;日粮RDP水平和NFC种类在影响黄色瘤胃球菌（Ruminococcus flavefaciens）和液相产琥珀酸丝状杆菌（Fibrobacter succinogenes）的16S rDNA拷贝数方面存在交互作用,蔗糖组固相R. flavefacien在低RDP下的拷贝数和菊粉组液相F. succinogenes在高RDP下的拷贝数分别趋向于低于（P=0.06）和低于（P＜0.01）淀粉组;③增加日粮RDP水平可以提高所有处理组的总挥发性脂肪酸产量（P＜0.01）和总微生物氮（microbial nitrogen,MN）流量（P＜0.01）;主效应上,果胶组的乙酸摩尔比例（P＜0.05）和乙丙比最高（P＜0.01）;不论RDP水平,蔗糖和菊粉组的丁酸摩尔比例均高于其它处理组（P＜0.01）;低RDP下各处理组的总MN流量差异不显著,但提高RDP使蔗糖和果胶组的总MN流量分别高于（P＜0.01）和趋向（P=0.10）高于淀粉组;主效应上,淀粉组的N利用效率低于蔗糖（P=0.04）和果胶组（P=0.05）。【结论】日粮RDP水平和NFC类型在影响瘤胃发酵、微生物合成和纤维分解菌菌群方面存在交互作用,当日粮中含有足够的瘤胃可利用氮时,蔗糖和果胶较淀粉在促进微生物蛋白合成方面具有优势。     

结缕草的抗寒性与体内碳水化合物、脯氨酸、可溶性蛋白季节动态变化的关系

为了阐述结缕草抗寒性与碳水化合物、脯氨酸含量及可溶性蛋白含量季节动态变化的关系,在2008年10月-2009年5月期间,以‘兰引3号’结缕草(Zoysia japonica ‘Lanyin No.3’)为材料,研究在自然温度变化过程中,‘兰引3号’结缕草地下根茎碳水化合物、脯氨酸含量、可溶性蛋白含量的季节性动态变化及其与LT₅₀变化的关系。结果表明,在越冬前后,‘兰引3号’结缕草地下根茎LT₅₀呈先降低后升高的季节变化趋势,可溶性总糖含量、蔗糖含量、果糖含量及可溶性总糖/淀粉、脯氨酸含量、可溶性蛋白含量伴随田间气温变化均呈先升高后又降低的趋势,淀粉含量则呈先降低后又升高的趋势;‘兰引3号’结缕草地下根茎LT₅₀季节变化与可溶性总糖含量、果糖含量、可溶性总糖/淀粉、可溶性蛋白含量季节变化之间显著负相关,而与蔗糖含量、淀粉含量、脯氨酸含量的季节变化间不存在显著的相关性。     

草鱼SREBP-1基因的克隆及糖对其在肝脏中表达的影响

固醇调节元件结合蛋白(SREBPs)是调控糖脂代谢相关基因表达的关键核转录因子。为获知草鱼SREBP-1基因的序列及其在肝脏中的表达规律,本实验采用同源克隆和RACE方法获得了草鱼SREBP-1基因的部分cDNA序列,并通过生物信息学方法对该基因及所编码蛋白的结构特征进行了分析;采用实时荧光定量PCR技术,对SREBP-1基因在8种不同组织的表达规律及低糖(糖含量24%)和高糖(糖含量42%)投喂条件下肝脏中的表达水平进行了研究。结果显示,所克隆到的草鱼SREBP-1基因cDNA长4 760 bp,其中包括开放读码框3 426bp,编码1 141个氨基酸;草鱼SREBP-1具有一个典型的碱性螺旋-环-螺旋亮氨酸拉链结构(bHLH-zip);氨基酸序列比对结果显示,草鱼SREBP-1与其他鱼类的同源性在76%~88%之间,与斑马鱼的进化关系最近;草鱼SREBP-1基因在脑中的表达量最高,肝脏和肠次之,在肾脏、脾脏、肌肉、脂肪和性腺中均有少量表达;与对照组相比,SREBP-1基因在高糖诱导下表达量显著提高(P0.05),低糖诱导下没有显著性差异。研究表明,在高糖负荷条件下,草鱼肝脏中SREBP-1可能会促进糖的利用和转化,从而参与糖代谢调节过程,为丰富鱼类糖代谢调控机理提供研究资料,并有望为提高鱼类对饲料糖的利用效率提供理论依据。     

Does the “high sugar” trait of perennial ryegrass cultivars express under temperate climate conditions?

The objective was to evaluate water‐soluble carbohydrate (WSC) and crude protein (CP) concentration of perennial ryegrass (PRG) cultivars with different genetic potential for producing WSC under two contrasting agronomic managements in temperate climate (southern Chile). A 4 × 2 factorial design was randomly allocated to 24 plots (31 m² each, three blocks): four PRG cultivars (diploid standard cultivar, “2nSt”; tetraploid standard cultivar, “4nSt”; diploid high sugar cultivar developed in New Zealand, “2nHSNZ”; and tetraploid high sugar cultivar developed in Europe, “4nHSEU”) and two agronomic managements (“favourable,” defoliations at three leaves per tiller and nitrogen (N) fertilization rate of 83.3 kg N ha^?1 year^?1; “unfavourable,” defoliations at two leaves per tiller and N fertilization rate of 250 kg N ha^?1 year^?1). Herbage samples were collected in early spring, spring, summer and autumn. Concentration of WSC did not differ among cultivars in spring and summer, averaging 194 and 251 g/kg DM, respectively. The cultivar 4nHSEU had the greatest WSC concentration in early spring and autumn (187 and 266 g/kg DM, respectively) and the greatest CP concentration across samplings (average 230 g/kg DM). Favourable management improved WSC concentrations in early spring and summer and decreased CP in spring, summer and autumn. Annual DM yield did not vary with cultivar or management, averaging 8.43 t/ha. Within a 12‐month study at one site in a temperate environment in southern Chile, PRG cultivars have not shown a consistent expression of the “high sugar” trait, where a genetic × environment interaction might be operating.     

Dietary protein/carbohydrate ratio in low‐lipid diets for Senegalese sole (Solea senegalensis,Kaup 1858) juveniles. Influence on growth performance,nutrient utilization and flesh quality

Four isoenergetic (21 kJ/g dry matter, DM) and isolipidic (65 g/kg DM) diets containing different crude protein/total carbohydrate (CHO) ratios: 60/26, 56/30, 52/34 and 48/38, were tested in 22 g Senegalese sole for 104 days. Apparent digestibility coefficients (ADC) were not affected by the treatments, and all groups presented extremely low starch ADC values (22.8%–36.5%). Replacement of dietary protein by CHO did not affect daily growth index (0.9–1.0), but significantly increased voluntary feed intake of fish. Regression analyses demonstrated that digestible protein content, rather than digestible energy, was the main dietary factor influencing such feeding activity (R² = .952). A significantly increased feed conversion ratio was observed in sole fed increasing CHO contents. The dietary protein/CHO ratio did not influence whole‐body composition. Sole fed the 48/38 diet showed the lowest efficiency in terms of N and energy utilization. PUFA were the most represented fatty acid fraction in fillet, regardless of the dietary protein/CHO ratio, mainly due to the high content of DHA. Senegalese sole increase feed intake under low dietary protein/CHO ratios to ensure an adequate N intake. Such compensatory mechanism seems to be triggered to satisfy a specific protein metabolic requirement for energy purposes as tissue accretion remained unchanged.     

长白山岳桦体内碳素供应状况

低温条件常常驱动的碳缺乏导致高海拔处植物生长缓慢,生长季的高寒低温更是限制高海拔地区树木向上分布的关键因素之一。高海拔地区的不利     

Relationships between reproductive output, morpho-physiological traits and life span in Lesquerella (Brassicaceae)

The development of perennial industrial crops could contribute to increase agriculture sustainability and yield stability in arid environments. Since perennial plants allocate resources preferentially to perpetuation and to structural and functional characters that provide drought tolerance, they tend to have lower reproductive output (yield) than their congeneric annuals. Four species of Lesquerella native to arid regions were evaluated to understand the relationships between reproduction, drought tolerance, and their association with the plant's life span. We assessed the following set of characters (defined as plant strategies): phenology, gas exchange, specific leaf area, leaf area ratio, total biomass and biomass allocation. Annual (Lesquerella gracilis and Lesquerella angustifolia) and perennial (Lesquerella mendocina and Lesquerella pinetorum) species were compared under water limiting conditions. Within this set of species differences in structural and functional characters were observed. The annual, L. gracilis showed a plant strategy characterized by high reproductive output, harvest index (HI) and specific leaf area (SLA). L. mendocina (perennial), produced more total biomass, but had a low reproductive output, and also showed characters that provide drought tolerance (high allocation to roots-root mass ratio (RMR), and storage-total non structural carbohydrates (TNC) and low SLA). The annual L. angustifolia and the perennial L. pinetorum had intermediate plant strategies (i.e. intermediate values of traits typically related with annual or perennial life span). In the case of L. pinetorum we found some traits common to L. mendocina: long vegetative period, high biomass, CO₂ assimilation rate (A), and water use efficiency (WUE), and low SLA. The high reproductive output in L. pinetorum was a result of both, higher total biomass and longer growing season compared to the annuals, and of higher HI in relation to the other perennial. These differences in plant strategies among perennial Lesquerella show that there are different combinations of traits that could be used as criteria for the selection of a perennial crop in programs of domestication for Patagonia and others arid lands.     

12个苜蓿品种根部非结构性碳水化合物含量的季节性变化

研究不同紫花苜蓿品种晚秋和早春时期根部非结构性碳水化合物含量的季节变化动态,以期为当地紫花苜蓿推广应用提供理论依据。以国内外12个紫花苜蓿品种为试验材料,通过测定其在晚秋和早春时期根部可溶性糖、还原糖、总糖和淀粉含量,对不同紫花苜蓿品种抗寒生理特性进行了比较研究。结果表明,秋季和春季不同苜蓿品种根部可溶性糖、还原糖和总糖含量以及可溶性糖/淀粉值差异显著(P0.05),淀粉含量在秋季差异显著(P0.05),春季差异不显著(P0.05)。从晚秋至翌年早春,不同苜蓿品种根部非结构性碳水化合物含量下降幅度差异较大,可溶性糖含量下降率为8.71%~41.43%,淀粉下降率为51.21%~79.37%,还原糖下降率为17.47%~56.16%,总糖下降率为26.10%~48.78%。聚类分析可将12个苜蓿品种分为三类:第一类为根部低淀粉含量类,包含M1和M8号二个品种,淀粉含量低于3.0%;第二类为根部高淀粉含量类,包含M3、M4、M6、M7和M11号五个品种,淀粉含量在3.91%~4.82%之间;第三类为根部高可溶性糖含量类,包括M2、M5、M9、M10、M12五个品种,可溶性糖含量在8.0%以上,淀粉含量在3.0%~4.0%之间。