Potassium uptake characteristics of prunus rootstocks: Influence of solution Ca/Mg ratios and solution nickel

Abstract

Nutrient solution experiments were conducted in the growth chamber to study the influence of rootstock, solution Ca/Mg ratios and solution nickel on K uptake. The experimental plants were one‐year‐old prune trees: ‘French’ prune (Prunus domestica L.) scions grafted on Myrobalan 29C (P. cerasifera Ehrh.), Marianna 2624 (P. cerasifera x P. munsoniana?) or Nemaguard (P. persica x P. davidiana) rootstocks. Ion uptake parameters Imax, Km, and Cmin were calculated from ion depletion measurements over a 6 to 10‐hr period.

With K solution concentrations initially adjusted to 100 μM, K uptake rates of Prunus rootstocks were constant down to approximately 20–30 μM, then declined. Rootstocks were able to deplete solution K to concentrations less than 1 μM. There were no significant differences in K uptake parameters among the rootstocks tested.

Varying solution Ca/Mg ratio from 2.75/1 to 1/4 (Ca + Mg = 3.75 mM) had no effect on K uptake. Potassium uptake rates of Myrobalan 29C rootstocks in the presence of 100 μM nickel were not significantly different from those in the absence of nickel. Rates of nickel uptake were significantly lower than those of K. After eight days of pretreatment in solutions adjusted daily to 100 μM Ni(NO₃)₂, prune leaves began to show signs of interveinal chlorosis. Potassium uptake by nickel pretreated trees was not significantly different from that by control trees. Results are discussed in relation to field observations of K deficiency in prune orchards.     

硅、镁、硼肥对甘蔗产量和产糖量影响的研究

在硅、镁、硼营养较缺乏的甘蔗田，进行硅肥、镁肥、磷肥的施肥效应试验，结果表明：硅、镁、硼肥及其不同施肥水平对甘蔗的株高、茎径、锤度、产量和产糖量有明显的影响。施用硅肥使甘蔗锤度、产量和理论产糖量分别比对照增加0.42～1．11，11．04～14．96t／hm^2和1．84～2．10t／hm^2；施用镁肥分别比对照增加0.93～1．26，4．02～9．55t／hm^2和0．99～1．53t／hm^2；施用硼肥分别比对照增加0．41～1．20，5．00～10．00t／hm^2和0．80～1．82t／hm^2。     

Effects on soils and leaching after application of dolomite to an acidified forested catchment in the Lake Gårdsjön watershed,south-west Sweden

The dry forest soils (80%) of a 3.3 ha catchment in Gårdsjön, were treated with 1.5 ton/ha dolomite in 1984. In half the catchment an additional dose of 4.5 ton/ha was added in 1986 (i.e. totaly 6 ton/ha). By 1991 the concentrations of exchangeable calcium and magnesium had increased by 450% to 800% in the humus layer and upper 0–5 cm of the mineral soils and by 500% and 300%, respectively, in the 5–10 cm and 10–20 cm soil depth in the 6 ton/ha part. By 1.5 ton, Ca and Mg increased in humus and 0–5 cm in the mineral soil. Potassium decreased in the humus and the mineral soil with both 1.5 ton and 6 ton per ha. The accumulated output of K by runoff was however only 1 kg during the 6 years until 1992, which indicates that the losses from the soil also may have resulted in increased uptake by the forest. Tree growth and nutrient content in current needles was, however, unchanged. Increased contents of Mg, Ca and Zn was observed in some species of ground vegetation. Nitrate and ammonium concentrations and fluxes in runoff were identical to the reference catchment, while inorganic Al and Mn decreased by 40–50% and H⁺ by 30%. The accumulated extra output by runoff of Mg was about 7% and of Ca 0.6% of the amounts applied by the two treatments in 1984 and 1986.     

Evaluation of Alternative Methods of Applying Sulfur Fertilizers to Chrysanthemums

ABSTRACT

Previous research has shown that supplying adequate sulfur (S) continuously in combination with reduced amounts of nitrogen (N) will produce a quality plant. However, not all commercially available fertilizers use the same source of S, contain the same or optimal concentration of it, or contain any S at all. Additionally, nutrient incompatibility can occur if all the macronutrients are combined in one solution or one dry fertilizer. Thus, the objective of this research was to determine the effect of different methods of application and different types of S fertilizers on chrysanthemum growth. Two experiments were conducted in which three S sources (H₂SO₄, MgSO₄, and K₂SO₄) were applied in combination with three N concentrations (50, 100, and 150 mg L^?1) as fertilizer treatments. Sulfur was applied at 10 mg L^?1, either continuously—by slightly acidulating the fertilizer solution with H₂SO₄—or in one, two, or three single, discrete applications as either K₂SO₄ or MgSO₄. Leaf N concentration was greatest when 100 or 150 mg N L^?1 was applied. As expected, S applied continuously by slightly acidulating the fertilizer solution with sulfuric acid resulted in higher leaf S concentration and larger flower diameter than under any of the other treatments. Together, plants fertilized with S continuously at 10 mg S L^?1 and N at 100 mg L^?1 were the largest, had the largest flower diameter, and contained the greatest leaf N and S concentrations. Sulfur concentration in the mix was highest and N concentration lowest when S was supplied continuously. Thus, if growers need to supply S and acidulate their water, sulfuric acid would be the best choice. If there are concerns about possible S contamination in landfills or in mix recycling, either potassium or magnesium S, applied multiple times as single applications in combination with 100 or 150 mg N L^?1, may be a better choice.     

施钙与覆膜栽培对缺钙红壤花生Mg、Fe、Zn吸收,积累及分配的影响

为探究施钙与覆膜栽培对花生植株Mg、Fe、Zn营养改善状况,以大籽品种湘花2008和南方典型第四纪红土发育的缺钙酸性红壤为试验材料,设置3个基施钙肥梯度[不施钙(Ca0)、施钙375 kg·hm^-2(Ca375)、施钙750 kg·hm^-2(Ca750)]和2种栽培方式[露地(OF)、覆膜栽培(PF)],采用土柱栽培,研究施钙与覆膜栽培对植株Mg、Fe、Zn含量,积累及籽仁分配系数的影响。结果表明,增施钙肥明显提高了花生茎秆、根系、果针、籽仁中Mg和Fe含量,其中,Ca750-OF处理较Ca0-OF分别提高19.2%、10.4%、38.6%、3.1%和21.5%、30.9%、27.5%、20.0%,但显著降低了叶、茎秆、果壳及籽仁中Zn含量。覆膜栽培提高了茎秆、果针、籽仁Mg含量及果壳、籽仁Zn含量,较露地栽培分别提高10.8%、12.2%,但降低了花生叶、茎秆、根系Fe和Zn含量。施钙与覆膜栽培增加了花生植株、生殖体(针壳、籽仁)Mg积累量、籽仁Mg分配系数。施钙实现花生整个植株体Fe积累量的富集,其籽仁Fe分配系数显著提高68.8%,而覆膜栽培籽仁Fe和Zn积累量显著高于露地栽培。增施钙肥降低了花生营养体Zn积累量,显著提高了籽仁Zn积累量及籽仁Zn分配系数,提高效果表现为Ca750>Ca375。年份、施钙处理、栽培措施三者间对籽仁积累量及分配系数存在正交互作用。植株Ca积累量与Mg、Fe积累量呈极显著正相关,存在协同吸收关系。综上,施钙与覆膜栽培促进了土壤活化,有利于花生植株中Mg、Fe的吸收,加快Mg、Fe、Zn向籽仁的富集,进一步扩大“库容”。本研究结果为南方酸性缺钙红壤旱地改良及花生高产高效栽培提供了理论依据。     

Phosphate Fertilizers for Sugarcane Used at Pre-Planting (Phosphorus Fertilizer Application)

Phosphate applications are still rare in sugarcane cultivation and can be done with phosphorus fertilizers of residual over. This study aims to evaluate the agronomic efficiency of phosphate fertilization before sugarcane planting and its effect on sugarcane yield. The study was carried out over three crop cycles at the Jalles Machado sugar-mill in Goianésia, GO, Brazil. The treatments consisted of five different phosphorus sources (soluble and insoluble) applied at a rate of 300 kg ha^?1 phosphorus pentoxide (P₂O₅). The phosphorus fertilizers used were: triple superphosphate, mono-ammonium phosphate (MAP), Arad rock phosphate, Itafós rock phosphate, and magnesium term phosphate. The effects of these fertilizers were evaluated by plant height (ground to Top Visible Dewlap; TVD), leaf phosphorus content, agronomic efficiency, and sugarcane yield from cane-plants, first ratoon, and second ratoon. Magnesium term phosphate and triple superphosphate resulted in greater plant-cane height. Leaf phosphorus concentrations were highest with applications of MAP, magnesium term phosphate, and triple superphosphate. Phosphate applications did not affect sugarcane plant yield, but did increase ratoon yield. In general, the residual effect of insoluble phosphate increased over the years. The agronomic efficiency (AE) of phosphate was (in descending order): triple superphosphate (100%), term phosphate (89%), MAP (80%), Itafós rock phosphate (67%), and Arad rock phosphate (60%).     

缺镁胁迫对龙眼苗期氮代谢的影响

采用溶液培养方法研究了缺镁胁迫对龙眼苗期氮代谢的影响。结果表明 ,缺镁胁迫下 ,龙眼叶片硝酸还原酶 (NR)活性下降 ,游离氨基酸总量增加 ,水解氨基酸总量减少 ,蛋白质合成受阻而分解加剧 ;核酸酶 (RNase)活性提高 ,核糖核酸 (RNA)、脱氧核糖核酸 (DNA)含量降低 ,缺镁对RNA的影响比DNA大 ;活性氧 (O2-)净产生速率增加。统计分析表明 ,缺镁胁迫下 ,龙眼核酸和蛋白质含量下降是其合成受阻、分解加剧以及活性氧毒害综合作用的结果     

缺镁对龙眼光合产物生产和分配的影响

缺镁对龙眼 (DimocarpusLonganaLour.)光合产物的生产和分配有明显的影响。缺镁胁迫下 ,龙眼叶片单位面积和单位重量的叶绿素、类胡萝卜素含量均降低 ,光合速率下降 ,叶绿体亚显微结构发生明显的改变 ,叶绿体中可见有大量的淀粉粒。随着缺镁胁迫程度的加重 ,14 C -光合产物在标记叶中的滞留量增加 ,输出率降低。叶片非还原糖、淀粉含量增加 ,茎秆、根系的非还原糖尤其是淀粉含量降低。本文还就缺镁影响龙眼光合产物生产和分配的机理进行了讨论     

石灰性土壤交换性钙和镁测定方法的研究

石灰性土壤交换性盐基组成的测定,通行的方法是采用70%乙醇溶液反复洗盐,再经pH 8.50.1 mol L-1氯化铵-70%乙醇(CH3CH2OH)溶液进行多次交换处理,测定交换液中的K+、Na+、Ca2+、Mg2+浓度。但此方法常常受操作步骤繁琐,以及土壤中碳酸盐的溶解量因多次浸提而增加的困扰,最终导致测定结果偏高。基于上述原因,选择不同浓度、不同pH的NH4OAc和NH4Cl 10种交换剂,对比分析10种交换剂中的碳酸盐溶解度和土壤交换性钙镁含量。结果表明,pH=8.5 1 mol L-1氯化铵-70%乙醇(CH3CH2OH)溶液较适合石灰性土壤交换性盐基的测定。此新方法是先经70%乙醇(CH3CH2OH)溶液洗盐,再用pH8.5 1 mol L-1氯化铵(NH4Cl)-70%乙醇(CH3CH2OH)溶液进行一次性交换处理,然后测定交换液的K+、Na+、Ca2+、Mg2+浓度,简化了操作程序的同时有效抑制了土壤碳酸盐的溶解,降低了测定结果的偏差。     

钾镁水平对番茄苗期生长、根系形态及钾素吸收和生理利用效率的影响

采用水培方法,研究不同钾、镁水平对"天福冠露"和"毛粉802"两种番茄幼苗生长、根系特征及钾素吸收、利用效率的影响。结果表明,钾、镁水平(8 mmol/L、1 mmol/L)处理的植株鲜重、干重及钾、镁水平(4 mmol/L、4 mmol/L)处理的株高显著高于其他处理。随钾、镁水平升高,两种番茄植株的根长、"天福冠露"植株的根直径、根体积和分根数先减少后增加;番茄植株钾素吸收率显著提高,生理利用效率显著降低。钾、镁水平(8 mmol/L、1 mmol/L)处理的植株根长、根表面积、根直径及根体积显著高于缺钾处理。钾、镁水平(4 mmol/L、4 mmol/L)处理,两种番茄植株根长、根表面积、根体积和分根数均显著高于缺镁处理,"天福冠露"植株钾含量显著高于"毛粉802",而钾素生理利用效率显著低于"毛粉802"。与其它等钾处理相比,缺镁植株钾素积累量最低、生理利用效率最高,镁过量处理的植株钾素生理利用效率显著降低。