Plant water stress and K starvation reduce absorption of foliar applied K by olive leaves

Three-month-old mist-rooted ‘Picual’ olive cuttings were transplanted into 2-l plastics pots containing perlite as substrate and fertigated with a complete nutrient solution containing 0.05, 0.1 or 2.5 mM KCl depending on the experiment. In the first experiment, plants were sprayed with RbCl (Rb⁺ is a K⁺ analog) at a rate of 4% at 63 days after transplanting (DAT). Foliar Rb⁺ uptake through leaves increased with K⁺ concentration in the nutrient solution, indicating that foliar Rb⁺ uptake was lower when plants were K⁺ deficient than when they were adequate. On the contrary, it was observed that translocation of Rb⁺ from leaves to other organs of the plant was higher under K⁺ deficiency conditions. In the second and third experiments, when differences appeared on shoot length due to K⁺ nutritional status (0.05 or 2.5 mM KCl) at 63 DAT, a group of plants were subjected to water stress during 7 weeks. On the other hand, another group of plants (control plants) did not receive any water stress treatment during the experiments. After this period of 7 weeks, all plants were sprayed with RbCl at 4%. Leaf K⁺ concentration diminished in water-stressed plants independently of plants nutritional status. Foliar Rb⁺ uptake through leaves was restricted by water stress either in plants with low K⁺ (0.05 mM KCl) or plants with high K⁺ (2.5 mM KCl). Translocation of Rb⁺ from leaves was greater under water stress conditions in both K⁺ nutritional statuses. In conclusion, the results obtained could explain the irregular response in olive trees to foliar K⁺ sprays, particularly, when they grow in rainfed orchards.     

Response of apple trees to boron fertilization under conditions of low soil boron availability

The aim of the study was to examine the effect of boron (B) fertilization on the vegetative and the reproductive responses of apple (Malus domestica Borkh.) trees grown at low soil B availability. The experiment was carried out in 2005 under a greenhouse on 5-year-old ‘Jonagold’ apple trees/M.9 EMLA planted singly in 50-L containers filled with a sandy loam soil with hot water-soluble B concentration of 0.32 mg kg⁻¹. The trees were fertilized with B as foliar or soil application. Foliar B sprays were applied at the stage of pink bud, beginning of flowering, petal fall, and 10 days after flowering, at a solution concentration of 0.03%. Soil B fertilization was done at the bud break stage at a rate of 2 g per tree (27 mg B kg⁻¹ soil). The trees untreated with B served as the control. The results showed that soil B fertilization improved root development and tree vigor. Leaves of trees supplied with B to the soil had higher B concentration and chlorophyll, net photosynthetic rate, stomatal conductance, and activity of catalase and glutathione reductase than those of the control plants. Boron fertilization, regardless of application mode, increased fruit yield; the efficiency of foliar B sprays was higher than soil B application. Apple fruits of trees fertilized with B to the soil were bigger, more colored, richer in B, and had higher soluble solids concentration, and titratable acidity compared to those of the control trees.     

氮磷钾均衡管理对戈壁滩日光温室有机基质栽培春茬黄瓜产量与养分吸收的影响

采用田间小区试验,研究了氮磷钾均衡管理对戈壁滩日光温室有机基质栽培春茬黄瓜产量与养分吸收的影响。结果表明:1日光温室春茬黄瓜栽培基质营养主要限制因子是氮和钾,施磷也有一定增产效果,施氮、施钾和施磷分别增产51.2%、45.2%和10.0%。2推荐施肥处理较习惯施肥处理能大幅度增加产量和经济效益,平均增产35.7%,增收40.7%;推荐施肥处理产量和经济效益均略高于高氮和高钾处理,产量分别增加4.3%和3.8%,经济效益分别增加4.4%和3.9%。3推荐施肥处理能显著促进黄瓜对氮磷钾的吸收,提高化肥氮磷钾利用率,化肥氮、磷和钾利用率分别达到31.7%、34.1%和78.9%,而习惯施肥处理的化肥氮、磷和钾利用率分别仅为4.6%、0.9%和11.7%。4本试验条件下日光温室有机基质栽培春茬黄瓜适宜N、P2O5和K2O用量范围分别在350~430、135~160、370~430g·m-3(基质)之间,生产1000kg黄瓜产品对N、P2O5和K2O的推荐量范围分别在2.0~2.4、0.8~0.9、2.1~2.3kg之间。     

不同无机盐离子对平菇菌丝体生长的影响

在基本培养基中添加不同浓度的K₂SO₄、MgSO₄、Na₂SO₄,研究了无机盐（阳离子）对平菇菌丝体生长的影响。结果表明:0.3%K₂SO₄、0.4%K₂SO₄、0.5%K₂SO₄和0.2%MgSO₄能显著地促进平菇菌丝的生长。     

Effects of Ascorbic Acid and Reduced Glutathione on the Alleviation of Salinity Stress in Olive Plants

The aim of this study was to evaluate the effects of low molecular mass antioxidants and NaCl salinity on growth, ionic balance, proline, and water contents of ‘Zard’ olive trees under controlled greenhouse conditions. The experiment was carried out by spraying 2 mM of ascorbic acid (Asc) and 3 mM of reduced glutathione (GSH) on the plants that were treated with two salinity levels (0 and 100 mM NaCl) on their root medium. Plant growth parameters (leaf fresh weight, leaf dry weight, leaf number, total fresh weight, and total dry weight) were significantly improved by Asc compared with growth parameters in GSH and control plants. Higher concentrations of Na⁺ and Cl^– were observed in salt-stressed plants, while Na⁺ and Cl^– concentrations were decreased in the olive leaves that were sprayed with Asc. Salinity in the root zone caused a considerable decline in both K⁺ concentration and K/Na ratio. K⁺ concentration and K/Na ratio were significantly increased by application of Asc on plant leaves. Salinity caused an increase in electrolyte leakage (EL) compared with the control plants. Lowest EL and tissue water content (TWC) was obtained in Asc-sprayed plants, whereas TWC was increased in salt-stressed plants. Plants were subjected to salt stress and showed a higher relative water content (RWC) than the control plants. Salt stress induced proline accumulation in olive leaves. In conclusion, exogenous application of Asc is recommended to improve tolerance of olive plants under saline conditions.     

滴灌条件下不同施钾量对甘蔗产质量的影响

为了评估甘蔗生产上应用滴灌施肥技术的效应,比较了滴灌系统及传统方法施用钾肥对甘蔗产量和品质的影响以甘蔗品种粤糖00—236为试材．进行了1年（2006～2007）露天盆栽滴灌种植试验。设置了4个通过滴灌系统施用的钾肥（KCl）水平,K1：10g／盆,K2：15g／盆,K3：20g／盆和K4：30g／盆,滴灌各处理施尿素15g／盆,和1个常规施肥方式（肥料施用量为尿素30g／盆和KCl30g／盆）。试验结果表明．滴灌施肥显著促进了甘蔗的生长．比常规施肥的甘蔗产量获得显著提高,K1、K2、K3和K4处理的每盆蔗茎收获量分别比常规管理的增加了19．2％、38．6％、45．9％和56．4％、滴灌条件下,施钾量不同对甘蔗产质量有显著影响．甘蔗产量随施钾量的增加而增加．但过多施用钾肥对甘蔗品质有负面影响.在甘蔗生产上应用滴灌施肥技术,可以节省钾肥的施用量。而且钾肥用量为常规推荐施用量的一半即可获得较常规施犯高三成以上的产量,通过滴灌系统施用钾肥既有经济效益．又有环境效益．     

氮、磷、钾肥对红枣产量和品质的影响

研究了氮磷钾肥对6a树龄红枣产量和品质的影响。结果表明:新疆南部红枣最高产量施肥量为N691.5 kg/hm²,P₂O₅ 577.5 kg/hm²,K₂O 72 kg/hm²,施用比例1:0.84:0.11。采用平衡施肥能增加红枣产量,降低红枣果实中总酸度,并能增加红枣果实中水解还原糖和VC含量,从而提高红枣产品品质,增加效益。红枣果实中总酸度随氮肥施用量增加而增加;磷钾肥能降低总酸度。当氮、磷、钾肥分别控制在600、180～450、75kg/hm²时能显著提高红枣果实中水解还原糖和VC含量。     

北京市设施蔬菜施肥状况及减施潜力分析

通过对北京市352 个设施蔬菜地块的施肥状况进行实地调研，查明设施蔬菜施肥现状及存在问题，估算肥料减施潜力。结果表明，北京市设施蔬菜养分投入量普遍超过推荐施肥量（养分超标率＞72%）。不同设施类型施肥量差异较大，其中日光温室每季蔬菜平均氮磷钾（N、P₂O₅ 和K₂O）投入总量分别为858 、409、572 kg · hm^-2，明显高于塑料大棚每季蔬菜平均氮磷钾投入总量593、317、438 kg · hm^-2。设施蔬菜养分主要来源于有机肥基施，对日光温室和塑料大棚养分投入总量的贡献分别为66% 和52%。不同蔬菜种类肥料减施潜力巨大，其中甘蓝、黄瓜和茄子总养分相对减施潜力分别为61%～62%、43%～48% 和18%～47%。日光温室和塑料大棚氮磷钾养分投入比例（N∶P₂O₅∶K₂O）分别为1∶0.47∶0.66和1∶0.53∶0.73，表明钾肥比例相对不足。建议加快设施蔬菜水肥一体化技术的推广应用，加强设施蔬菜施肥技术指导，尤其要降低日光温室的氮、磷肥投入量，避免过量施肥带来的资源浪费和环境污染。     

Effects of irrigation with treated wastewater on olive tree growth,yield and leaf mineral elements at short term

In arid regions, such as Tunisia, the reuse of treated wastewater (TWW) in agriculture can be a sustainable solution for water scarcity. A two-year field experiment was conducted in order to investigate the short-term effects of TWW on olive growth, yield and concentration of total nitrogen (N_t), potassium (K), phosphorous (P), and heavy metals (i.e. Zn, Mn, Pb and Cd) in olive leaves. Olive trees were subjected to the following irrigation treatments: (i) trees irrigated with well water (WW) and (ii) trees irrigated with treated wastewater (TWW). For both treatments, the TWW and WW were applied at a rate of 4.5 m³ day⁻¹ tree⁻¹ (5000 m³ ha⁻¹ year⁻¹). After two years, non-significant injuries caused by salts and/or heavy metals were observed on shoot growth of trees irrigated with TWW. The application of TWW significantly increased concentration of N_t, P and K in the leaves, whereas heavy metals (Zn and Mn) showed a significant increase only after the second year of irrigation.     

Mobilization of nitrogen in the olive bearing shoots after foliar application of urea

Mature ‘on’ and ‘off’ ‘Manzanillo’ olives trees with three healthy branches of 10–12 cm in diameter were selected to determine changes in nitrogen levels in the bearing shoots after foliar application of urea. Each selected branch of each tree received one of the following treatments: (i) control without urea application; (ii) foliar application of urea to all the current-season leaves; and (iii) foliar application of urea to all the one-year-old leaves. Urea was applied in May, four days after full bloom in the ‘on’ year trees. Each treated leaf was immersed in a test tube containing a 4% urea solution and 0.1% Tween 20 for 5 s. Bearing shoots, composed of both one-year stems and leaves and current-season stems and leaves, were collected at intervals from the beginning of the experiment until 64 days after urea application. Nitrogen was determined in stems and leaves from each part of the bearing shoot, and in fruits during the ‘on’ year. Nitrogen uptake from the leaves was rapidly mobilized from the older to the current-season leaves of the bearing shoot, and thereafter to other storage organs of the tree or to the fruit, which is the largest nitrogen sink in the bearing shoot. No translocation of nitrogen from the current-season leaves to older leaves was observed. The rapid translocation of nitrogen from the younger leaves to other storage organs of the tree could explain the insensitivity of leaf analysis to detect excess nitrogen, since mature leaves from current-season shoots must be sampled to determine the nutritional status of the tree. The failure of leaf analysis to detect excess nitrogen may be a cause of nitrogen over-fertilization in olive orchards.     

辽西温室甜瓜一年一大茬栽培优质高产施肥技术

针对喀左县日光温室甜瓜一年一大茬栽培所面临的土壤障碍明显、产量不高、品质下降、病虫危害加重等实际问题,通过改变传统施肥方法,使上述问题得到了一定缓解。在合理应用有机肥基础上,根据温室土壤养分状况和甜瓜需肥规律,开展了肥料应用种类、比例、数量、最佳施肥时期和方法研究,探索出一套适合喀左地区日光温室甜瓜一年一大茬栽培的高产高效施肥技术,从甜瓜不同生长发育时期出发,总结出适量应用育苗肥、施足基肥、根据不同生长发育时期追肥、做好叶面喷肥、适量应用微肥等合理施肥方法,使温室甜瓜每667 m²产量较农民习惯施肥增加905.61 kg,效益增加5 433.66元。     

叶面喷施沼液肥对温室香瓜茄叶片光合特性、果实产量和品质的影响

以香瓜茄为材料,在日光温室条件下,于果实发育期叶面喷施沼液肥,研究沼液肥施用浓度及其与土壤追肥配合对香瓜茄叶片光合特性和果实产量与品质的影响.结果表明,稀释100倍沼液肥处理的叶片总氮和叶绿素质量分数分别为35.7 g·kg-1和1.129 mg·g-1,显著高于稀释400倍沼液肥的处理和对照,沼液肥配合土壤追肥时叶片...     

Calcium and Potassium Foliar Sprays Affect Fruit Skin Color,Quality Attributes,and Mineral Nutrient Concentrations of ‘Red Delicious’ Apples

This study was conducted to evaluate the influences of foliar spray of potassium (K), calcium (Ca), and their combination on the fruit red skin color and quality attributes of ‘Red Delicious’ apple under conditions of south central Iran with warm and dry summer, where low and high temperature differences are low. The trees were sprayed five times using 5 g L^–1 calcium chloride (CaCl₂) at 3-week intervals starting from 3 weeks after full bloom and three times (at 9, 12, and 15 weeks after full bloom) using 2.5 g L^–1 K sources [potassium chloride (KCl), potassium sulfate (K₂SO₄), and potassium nitrate (KNO₃)] during two growing seasons in 2013 and 2014. Anthocyanin, some physicochemical attributes, and fruit mineral concentrations were measured at harvest. Results showed that spraying with K, CaCl₂, and their combinations significantly increased fruit weight, sugar and anthocyanin concentrations, firmness, and K uptake. A combined foliar application of CaCl₂ and each of the K sources was more effective on the improvement of fruit color, firmness, fruit K and Ca uptake, and K/Ca ratio as compared to the case when either K or Ca was applied alone.     

Evaluating foliar nitrogen compounds as indicators of nitrogen status in Prunus persica trees

Mobile nitrogen (N) forms may be better N indicators of the N status of trees than total nitrogen (TN) due to their higher sensitivity to increasing N supply. A field experiment was carried out over a 3-year period to compare foliar concentrations of total N (TN), soluble N (SN), chlorophyll (Minolta SPAD readings), NH₄–N and NO₃–N as indicators of soil N availability in nectarine, Prunus persica L. Batsch, cv. ‘Fantasia’ (grafted on ‘Nemaguard’ peach, P. persica × P. davidiana) trees. Young trees were exposed to a range of fertilizer-N application rates. Based on correlation analysis, the best association between leaf N compounds with soil N supply and trunk diameter and/or fruit yield was obtained with TN and chlorophyll SPAD readings. Leaf concentrations of mobile N compounds (NH₄–N and NO₃–N) increased more than any other N compound under high N supply; however, their inconsistency among years and low leaf concentration difficult their use as N indicators. The optimum foliar TN for growth decreased with tree age, 4.4%, 3.6% and 3.3% in non-bearing 1-year-old trees, non-bearing 2-year-old trees and 3.3 fruit-bearing 3-year-old trees. The optimum SPAD readings were 40 in 2-year-old trees and 42 in 3-year-old trees. Stable N compounds (TN and chlorophyll SPAD) could be used to N diagnosis in the zone of N deficiency, and soluble N compounds (NH₄–N and NO₃–N) to diagnoses N excess.     

Effect of acid or base pretreatment on auxin response of Damask rose cuttings

Hardwood stem cuttings of Damask rose (Rosa damascena Mill.) were dipped in H₂SO₄ or NaOH prior to application of 0, 1000, 2000 or 3000 mg l⁻¹ indolebutyric acid (IBA) or naphthaleneacetic acid (NAA). Acid pretreatment significantly increased root number, root length and root dry weight per cutting, but did not affect rooting-percentage. Rooting was significantly enhanced by auxin pretreatment, and NAA was superior in increasing root length and root fresh weight; 2000 mg l⁻¹ of auxin was the most suitable concentration for promotion of rooting under the conditions of the study.     

柑桔配施氮、磷、钾肥效应研究初报

本试验研究了在同一施氮水平下，不同水平磷、钾配施及施用不同种类钾肥对柑桔营养、产量及品质的效应。结果表明，紫色黄泥土锦橙园采用适当氮、磷、钾肥配合施用对提高单产及改善果实品质具有明显作用，以株施Ｎ４６０９、Ｐ_２Ｏ_４００ｇ、Ｋ_Ｏ５６０ｇ效果最佳，经济效益也最大。在一定范围内，叶片中的磷、钾养分含量都随磷、钾化肥用量的增加而提高。     

多效唑在苹果幼树上应用

红星、红富士苹果幼树施用多效唑后，对抑制新梢生长、调节枝条组成、促进花芽形成、提高坐果率、增加幼树产量、控制树冠增长均有明显效果，效果大小与施用方法、时期、药剂浓度和剂量、品种有关，土施比叶喷效果好。土施以３月或９月施入为宜，叶喷的最佳时期为５月上旬。土施的适宜剂量为０．５一１．０ｇ·ｍ~(-２)，叶喷最适浓度为１５００一２０００ｍｇ·１~(-１)。红星比红富士对药剂反应敏感。多效唑施后的持效期土施比叶喷的长，并随着剂量和浓度的增加而延长。土施０．５一１．０ｇ·ｍ~(-２)持效期为２一３年，叶喷１５００一２０００ｍｇ·１~(-１)的持效期仅为１年。     

Effect of alleviating products with different mode of action on physiology and yield of olive under drought

Two years old self-rooted Koroneiki olive trees (Olea europaea L.) were subjected to two irrigation regimes, i.e. the fully irrigated and the severely water stressed trees, while they were treated with three alleviating products of different mode of action. The products used were the osmolyte glycine betaine, the antioxidant Ambiol and the heat and irradiance reflecting kaolin clay particles. The effects of product application and water regime on leaf characteristics, shoot and root growth, photosynthesis, leaf compatible solids (carbohydrates) concentration and yield were evaluated. All products applied, exhibited significant alleviating action, based on the relative alleviation index. Irrigated trees exhibited greater growth than drought stressed ones, while the ameliorating products maintained the water content of the leaves under drought conditions and resulted in lower leaf tissue density. On the other hand carbon assimilation rate, stomatal conductance and intrinsic water use efficiency were significantly reduced under drought stress, while the opposite stood for intercellular CO₂. Drought stress resulted in elevated sucrose leaf concentration, while the application of Ambiol increased stachyose concentration and that of glycine betaine did the same with the mannitol concentration. Among the alleviating products tested in this experiment Ambiol and glycine betaine had a significant positive effect on leaf water content, photosynthesis and yield under both drought and well irrigated conditions.     

Effects of Bio-Bor Fertilizer Applications on Fruit Yield,Antioxidant Enzyme Activity and Freeze Injury of Strawberry

Deficiency of Boron (B) is widespread in the many parts of region of Turkey. So, the effects of boron and plant growth promoting bacteria (Bio-B) on the fruit yield, antioxidant enzyme activity and plant freeze injury of strawberry cv. Fern were investigated under field conditions between 2013 and 2014. The experimental plot was a completely randomized design with 4 replicates. Control and Bio-B were used as fertilizer agent in the experiment. Bio-B fertilizer was applied in three methods as soil, foliar and soil + foliar application methods to strawberry plants. Data through 2 years showed that the use of Bio-B significantly increased fruit yield, antioxidant enzyme activity and decreased freeze injury of strawberry leaf. Soil + foliar applications of Bio-B fertilizer increased to fruit yield compared to the control by 55.91?%. However, foliar application of Bio-B fertilizer increased to catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) enzyme activity compared with the control treatment 41.86?%, 48.99?%, and 26.59?%, respectively and decreased freeze injury of strawberry leaves 27.41?%. Overall, the results of this study suggest that Bio-B fertilizer application have the potential to increase the yield, antioxidant enzyme activity and decreased freeze injury of strawberry plants under field conditions.     

多效唑对桃树生长和结果的影响

应用多效唑对桃树进行土施和叶面喷布等不同方法,不同剂量的试验。土施0.125～1.0g/m~2,叶面喷布500ppm×2以上的浓度都可有效地抑制植株营养生长。它降低了新梢生长长度,抑制了副梢的发生和生长,以及干周的增长。多效唑在抑制营养生长的同时也促进了生殖生长,有效地促进花芽形成,降低了始花节位,增加了成花节位数和复花芽节位数。对果实大小也有促进作用。成倍地提高了早期产量。施用同等剂量,土施的效果优于叶面喷布。在我国中部地带,陇海沿线沙壤土上以0.25/m~2的剂量为好,第二年以后用量减半。在土施情况下它的“呆滞期”只1.0～1.5个月。土施应在旺盛生长前1.5～2.0个月以前施入。