菊芋氮磷钾吸收积累与分配特征研究

以“青芋1号”菊芋为试材,通过田间试验对菊芋全生育期的各器官内氮、磷、钾养分的吸收积累与分配特征进行了研究。结果表明,随生育期的延长菊芋各器官营养元素浓度呈下降趋势。营养元素吸收速率呈双峰曲线变化;营养元素积累总量表现为:氮钾磷。块茎形成前,营养元素主要存于茎、叶;块茎形成到块茎膨大始期,叶内营养元素分配量持续减少,块茎分配量持续增多,而茎内磷、钾则呈单峰曲线变化;块茎开始膨大后,营养元素在茎、叶的分配量均迅速减小,块茎分配量迅速增加。     

Jerusalem artichoke growth,development, and field storage. I. Numerical assessment of plant part development and dry matter acquisition and allocation

Abstract

Expanding commercial interest in the use of inulin as a bulking agent for artificial sweeteners, dietary fiber health supplement, fat replacement for processed foods, feed stock for fructose syrups, and a wide range of potential industrial products, has stimulated research on inulin‐containing crops such as the Jerusalem artichoke. To better understand the developmental physiology of the crop and to identify potential breeding objectives, the temporal pattern of development of individual plant parts (shoots, branches, leaves, flowers, stolons, tubers, and roots) and the allocation of dry matter into the same plant parts were monitored in the cultivar ‘Sunchoke’ over the entire growing season and during in situ field storage during the early winter, 32 weeks after planting. While number of shoots (～9) peaked in week 10, the number of branches (42.8), stolons (49.4), and tubers (85.5) reached a maximum 24–28 weeks after planting. Number of leaves (～525) peaked between weeks 20–24 after planting, as did number of flowers (～55). The Jerusalem artichoke allocated the major portion of its dry matter (dm) into aboveground plant parts during the first half of the growing season. Approximately 16 weeks after planting, the pattern of allocation shifted dramatically with: a) near cessation in the acquisition of dry matter; and b) the reallocation of existing dry matter from the aboveground organs into the tubers. By the 16th week after planting, 85% of the total dm was in the aboveground plant parts, but declined to 28% by the 30th week. Of the total dm, 92% was accrued during the first 16 weeks and only 8% thereafter. The shift in dry matter resources coincided with a dramatic decrease in leaf number and in leaf and branch dry weight. By the end of the season, the harvest index reached 0.70 and the tuber yield 14.61 dm ha^?1. Yield improvement could potentially be facilitated through lengthening the logarithmic period of carbon fixation and by earlier tuber induction and development.     

宁夏马铃薯氮、 磷、 钾养分的吸收累积特征

【目的】马铃薯氮、 磷、 钾养分吸收累积特点国内外已有不少报道,但在宁夏地区的生产条件下尚缺乏系统研究,马铃薯配方施肥技术推广中也缺少施肥参数,难以确定合理的施肥量。因此,针对宁夏地区马铃薯种植基地的土壤条件,系统分析马铃薯干物质累积和氮、 磷、 钾养分含量,探明其对氮、 磷、 钾养分吸收累积特点,以期为马铃薯的精准施肥提供科学依据。【方法】采用田间试验和室内测定相结合的方法。于2012年分别在宁夏西吉县、 原州区、 红寺堡和同心县马铃薯种植基地进行肥料田间试验,按照当地推荐的施肥量统一施肥量和施肥方法(农家肥、 70%氮肥、 全部磷、 钾肥基施,30%氮肥在现蕾期追施),在马铃薯不同生育期采集植株样品,测定不同器官干重和氮、 磷、 钾含量,分析不同生育期马铃薯干物质累积量、 氮、 磷、 钾含量及其吸收累积量的变化特点。【结果】1)从不同种植基地来看,红寺堡区马铃薯干物质累积量最高,其次是原州区和西吉县,同心县最低;马铃薯干物质累积量随生育期的推进而增加,符合Logistic曲线,幼苗期、 块茎形成期、 块茎膨大期和淀粉累积期的干物质累积量分别占总累积量的5%、 20%、 40%和35%。2)马铃薯植株氮含量随生育期而降低,其变异系数较大; 磷、 钾含量随生育期呈先增后减的变化态势,但变异系数较小; 氮、 磷含量叶片高于其他器官,钾含量茎秆中较高。3)马铃薯氮、 磷、 钾吸收累积量在红寺堡区最高,原州区和西吉县居中,同心县最低;苗期氮、 磷、 钾的吸收量分别占全生育期总吸收量的11%、 6%、 8%,块茎形成期占28%、 23%、 31%,块茎膨大期占36%、 39%、 41%,淀粉积累期占25%、 31%、 20%;成熟期块茎中氮和磷的累积量分别占各自总累积量的60%以上,钾的累积量占50%。【结论】供试土壤条件下,马铃薯干物质累积量及养分吸收量因种植基地、 生育期和器官不同而异。从不同种植基地来看,红寺堡区马铃薯的干物质及氮、 磷、 钾累积量较高,原州区和西吉县居中,同心县最低;干物质及氮、 磷、 钾累积量随生育期的变化符合Logistic曲线,具有明显的阶段性特点,块茎膨大期累积最多,块茎形成期和淀粉积累期次之;马铃薯根、 茎和叶中吸收累积的氮、 磷、 钾占同期总累积量的比例随生育期而降低,但块茎则相反,氮、 磷、 钾吸收累积量随生育期而增加,成熟期块茎中吸收累积的养分量占全株的一半以上。     

Nitrogen fertilization,irrigation, and harvest times affect biomass and energy value of Helianthus tuberosus L.

This study aimed to determine the effects of delayed harvest, irrigation and nitrogen fertilization on yield and fuel quality of the Jerusalem artichoke (JA) (Helianthus tuberosus L.). The biomass, calorific value, ash content and total calories per hectare of the Jerusalem artichoke were assessed in Inner Mongolia, China, at various harvest times, after irrigation and nitrogen application. The results showed that fresh and dry weights of tubers and underground biomass were higher when harvested after freezing; the dry yields of leaves and stems decreased with harvest time. In addition, irrigation significantly enhanced the yields of underground biomass, aboveground biomass and tubers, compared with non-irrigation conditions (p < 0.05). Interestingly, the highest yield was obtained with irrigation and treatment with nitrogenous fertilizers (20 to 50 kg ha^?1). The calorific values of tubers and roots were significantly higher for samples harvested after freezing (p < 0.05); the calorific values of leaves and stems significantly decreased with harvest time and without irrigation (p < 0.05). The calorific values of stems and leaves were higher than those of tubers and roots, when JA was harvested before freezing, and the opposite trend was obtained for harvest done after freezing. The highest calories per hectare was obtained in WN2 (585247.42 MJ ha^?1) on 30 September 2010 harvest. No correlation was found between the effects of water or nitrogenous fertilizers and ash content. However, the ash contents of stems, leafs, tubers and roots were significantly decreased (p < 0.05) with harvest time. Finally, in all treatment conditions, leaves produced the highest ash amounts among all plant parts, including stems, tubers, leaves and roots.     

Interactive effects of salinity and macronutrient level on wheat. II. Composition

Results of several studies show interactive effects of salinity and macronutrients on the growth of wheat plants. These effects may be associated with the nutrient status in plant tissues. The objective of this study was to investigate interactive effects of salinity and macronutrients on mineral element concentrations in leaves, stems, and grain of spring wheat (Triticum aestivum L. cv. Lona), grown in hydroponics, and the relation of these effects to yield components. Eight salinity levels were established from 0 to 150 mM NaCl, and 1, 0.2, and 0.04 strength Hoagland macronutrient solution (x HS) were used as the macronutrient levels. Sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chlorine (Cl), and phosphorus (P) in leaves, stems, and grain, NO₃ in leaves and stems, and total nitrogen (N) in grain were determined. Supplemental Ca, Mg, K, and NO₃ added to 0.2 x HS increased mineral concentrations in leaves and stems, but did not improve growth or yield in salinized wheat plants except moderately at 100–150 mM NaCl. In contrast, growth or yield was improved significantly when the concentration of macronutrients was increased from 0.04 to 0.2 × HS. In contrast to leaves and stems, mineral concentrations in grain increased (Na, Cl) or decreased (Ca, Mg, K) only slightly or were not affected (K) by salinity except at high salinity and low macronutrient level. Nitrogen and P concentrations in grain were not affected by salinity. Sodium and Cl concentrations in leaves and stems increased significantly, whereas K and NO₃ decreased significantly, with an increase in salinity regardless of the macronutrient level. The latter was also observed for Ca and Mg in leaves. Extreme Na/Ca ratios in plant tissues negatively affected grain yield production at high salinity with medium or high macronutrient levels and at low macronutrient level together with medium salinity. Even though strong and significant correlations between mineral concentration at grain maturity in leaves, stems, and grain and various yield parameters were observed, our results are inconclusive as to whether toxicity, nutrient imbalance, nutrient deficiency, or all of these factors had a strong influence on grain yield.     

CO2浓度升高与施氮对薏苡苗期营养元素吸收运输的影响

为明确大气CO₂浓度升高及氮肥施用对薏苡(Coix lacryma-jobi L.)苗期营养元素吸收运输的影响,本研究以兴仁白壳薏苡为试验材料,采用盆栽控制试验,通过人工气候箱模拟CO₂浓度升高,探究薏苡各器官中营养元素对CO₂浓度升高和施用氮肥的响应。结果表明,CO₂浓度升高使薏苡根中TOC含量显著增加15.82%;叶、茎中TP含量显著增加18.98%、29.41%(P<0.05);叶、根中N含量显著减少8.15%、8.31%(P<0.05);叶、茎、根中K含量无显著差异。施氮使薏苡叶、茎、根中N含量显著增加19.52%、28.42%、23.29%;叶、茎中TP含量显著增加14.60%、51.96%(P<0.05);根中K含量显著减少22.57%(P<0.05);叶、茎、根中TOC含量无显著差异。两者交互作用下,薏苡茎、根中N含量显著增加6.49%、8.99%;叶中TP含量显著增加15.33%(P<0.05);叶中N含量显著减少4.22%;叶、茎中K含量显著减少18.47%、33.25%(P<0.05);叶、茎、根中TOC含量无显著差异。在CO₂浓度升高条件下,薏苡叶片中中量元素S和微量元素Cu、Zn、Ni含量,分别显著减少18.06%、54.01%、37.96%、50.99(P<0.05);而茎中Mn、Cu、Zn、Ni含量,分别显著增加90.20%、70.55%、46.80%、149.50%(P<0.05)。CO₂浓度升高能促进Mg、S根向茎的运输以及Zn、Mn茎向叶的运输,施用氮肥能促进Fe茎向叶的运输。综上所述,CO₂浓度升高和氮肥施用会影响薏苡不同器官矿质离子的吸收及选择性运输能力,从而维持植物体内营养元素平衡。本研究结果可为深入认识未来大气环境变化下,薏苡对营养元素的需求变化特征,以及薏苡栽培中施肥策略的选择提供科学依据。     

冀中平原主栽山药品种的生长发育和养分累积特征

【目的】我国山药种质资源丰富,生态条件、栽培技术措施等各异,因此不同产地、不同品种的山药生长发育特性、养分累积及分配特性等均存在较大差异。本研究分析比较了冀中平原3个主栽山药品种的生长发育以及对氮磷钾养分的吸收、累积动态特征,以期为山药可持续生产中养分资源的高效管理与利用提供理论依据和技术支撑。【方法】以研究区域主栽的棒药、紫药和小白嘴为供试品种,在农民常规管理的山药田随机设置采样小区,分别于山药播种后的80 d、110 d 、140 d和180 d取样,测定山药根茎、茎、叶的鲜干重及氮、磷、钾养分含量。【结果】茎叶生物量随生育进程呈现先升后降的变化趋势,而根茎的生物量在收获期达到最高。棒药根茎鲜生物量显著高于紫药和小白嘴,但由于棒药栽培密度显著低于紫药和小白嘴,导致3个品种单位面积根茎的干物质积累量基本相当。对鲜干生物量累积动态特征的分析表明,与紫药和小白嘴相比,棒药鲜干生物量最大累积速率差异不大,但鲜干生物量快速累积持续期明显延长,最大累积速率出现的时间较晚。不同山药品种各养分的累积分配及养分利用效率不同,在整个生育期内,对氮磷钾养分的累积量3个品种均表现为K₂O ≥ N > P₂O₅,根茎 > 叶 > 茎,其中棒药对氮磷钾的累积量均最高,氮磷钾养分生产效率也均为最高,紫药和小白嘴差异不显著。对养分的累积动态特征分析结果表明,棒药对氮素和钾素的快速累积持续期最长,且最大累积速率也最高,但3个品种对磷素的累积动态特征差异不明显。【结论】供试3个品种中,紫药和小白嘴的生长发育及养分吸收累积动态特征相似,但与棒药明显不同。棒药的生物量大,产量高,养分的生产效率也最高,形成单位产量的养分需求量显著低于紫药和小白嘴。     

Seasonal changes and the effect of nitrogen- and potash-fertilization on the solanine and α-chaconine content in various parts of the potato plant

The concentration of solanine and α-chaconine in leaves and tubers decreased with the progress of the potato plant towards maturity. In stems an increase of these alcaloids up to the first part of the second stage of the vegetation period could be observed. With a higher level of nitrogen the concentration of both glycoalcaloids in leaves and stems increased, while in tubers a depression of the glycoalcaloid content was estimated. An increased level of potassium did not change markedly the concentration of glycoalcaloids in leaves and stems of the potato plant but decreased both alcaloids in the tuber.     

INFLUENCE OF NITROGEN SUPPLY ON CADMIUM ACCUMULATION IN POTATO TUBERS

The effect of different levels and forms of nitrogen (N) fertilizer on cadmium (Cd) concentrations in potato (Solanum tuberosum L.) tubers, a large component of the northern European diet, was investigated with the aim of decreasing the Cd content. A high and a low Cd-accumulating cultivar were used in two field trials and a pot experiment. The N fertilizers tested were balanced N- phosphorus (P)- potassium (K) 11-5-18 + micronutrients, alkaline calcium nitrate and acidic ammonium sulfate at levels of 60, 160, and 240 kg N ha^?1 at planting or (for the higher N doses) split between two or three occasions. The Cd concentration in tubers of both cultivars decreased when increasing the N fertilizer from 60 to 160 or 240 kg N ha^?1, indicating that Cd uptake and translocation are not positively correlated to the growth rate of the potato plant. A strong positive linear correlation was found between the Cd concentration in leaves at 77 days after planting and the Cd concentration in tubers at harvest, irrespective of N treatment, although the Cd concentration was three-fold higher in the leaves. The genetic variation in leaf and tuber Cd accumulation was consistent, regardless of the form of N fertilizer used. Ammonium sulfate decreased soil pH and increased tuber Cd concentration in both cultivars compared with NPK fertilizer, possibly due to increased amounts of plant-available Cd arising from the pH decrease after ammonium sulfate application. The tuber Cd concentration in the low Cd-accumulating cultivar increased when fertilized with calcium nitrate, an effect attributed to Cd availability being influenced by the increased Ca²⁺ concentration.     

两种菊芋耐盐差异研究

To explore genetic variability for two Jerusalem artichoke (Helianthus tuberosus) cultivars, N1 (the sixth-generation cultivated with 75% seawater irrigation for six years) and N7 (a general variety), a experiment was conducted to study the changes in physiological attributes under different concentrations (0%, 10% and 25% of seawater concentration in greenhouse and 0%, 30% and 50% of seawater concentration in the field) of seawater salinity stress. In the greenhouse experiment, decreases of dry growth rate, but increases of dry matter percentage and membrane injury occurred in both the genotypes at 10% and 25% seawater treatments, although lesser cell membrane damage was observed in N1 than N7. N1 accumulated greater contents of Na⁺, Cl^-, soluble sugar and proline in leaves compared with N7. In the field experiment, the yields of shoot, root and tuber, and the contents of total-sugar and inulin in tubers of N1 were higher than those of N7. Lesser degree of salt injury in N1 indicated that the relatively salt-tolerant cultivar had higher K⁺/Na⁺ ratio, lower Na⁺/Ca²⁺ ratio, and the salt-induced enhancement of osmotic adjustment.     

Effects of soil fertility on growth,tuber yield,nodulation and nitrogen fixation of yam bean (Pachyrhizus erosus (L.) urban) grown on a typic eutrustox

The tuberous legume, Yam Bean, (Pachyrhizus erosus (L.) Urban, has been utilized as a food crop for many centuries. The large, starchy tubers have higher aitrogen content than potatoes, cassava and taro roots with 20% or more of the N fraction as ureidoglyco‐lates. Yam Bean (Jicama) tuber growth within the neotropical regions of the world is influenced by soil productivity. The objective of this study was to determine effects of soil fertility treatments on tuber yield, nodulation characteristics and nitrogen fixation.

Highly significant increases in growth and tuber production resulted with P additions, and to Ca and K levels when combined with P. Nodule weight and nitrogenase activity were similar in response to factorial soil treatments as were the tuber and total above ground plant growth. Total ureide content of tuber epiperi‐derm tissue increased significantly with P, Ca, and P + Ca treatments and increased quadratically with increased K additions when combined with P, Ca, and P + Ca treatments. Multiple regression for nitrogenase = 3.4 g top wt. + 3.5 g tuber wt. + 4.9 g nodule wt. + 3.7 umol ureide, R² = 0.88 and C.V. = 16.5%. The percent nonstructural tuber carbohydrates was not significantly influenced by soil treatments although total tuber N content significantly increased with the P treatments. Content of plant nutrient elements within nodule cytosol generally increased significantly with addition of the corresponding element in the soil fertility treatments. Increased K content was quadratic for increased K additions with concomitant decrease in Na content having highly significant negative correlation (r = ‐0.72). Adequate available soil P, Ca and K favorably influenced Yam Bean tuber growth and nitrogen fixation with P a first limiting factor for desirable high tuber yields.     

摘叶对不同株型木薯品种产量和氮磷钾素积累分配的影响

  【目的】  叶片是作物进行光合作用的重要器官,与物质生产、养分吸收和产量形成有密切关系。研究留叶数对木薯养分积累和产量的影响,以期为木薯高产栽培和氮磷钾养分高效利用提供理论依据。  【方法】  采用裂区设计,以株型、品种、留叶数分别为主区、裂区和再裂区。试验以紧凑型品种‘华南205’(SC205)、‘桂热4号’(GR4)和伞型品种‘华南12号’(SC12)、‘华南15号’(SC15)为材料,设计12个留叶数处理(9、18、27、36、45、54、63、72、81、90、99和108片),分析了单株摘叶及成熟期单株的氮、磷、钾素积累量。  【结果】  随留叶数增多,单株摘叶的氮、磷、钾素积累量随之下降,单株鲜薯产量随之显著增加,成熟期全株和全生育期植株的氮、磷、钾素积累量随之呈显著增加或呈“单峰”或“双峰”趋势。不同品种不同元素的积累规律有差异。紧凑型品种单株摘叶的氮素积累量较伞型品种降低了4.56%,而磷、钾素积累量较伞型品种分别提高了10.23%、10.00%。紧凑型品种成熟期全株的氮、磷、钾素积累量较伞型品种分别提高了31.00%、42.48%和50.92%。在成熟期,留叶数增多,在块根和叶片中的氮、磷、钾素分配率随之提高,而在茎秆中的氮、磷、钾素分配率随之下降,氮、磷、钾素收获指数随之呈增加或“单峰”或“双峰”趋势。紧凑型品种氮、磷、钾素收获指数高于伞型品种,两株型分别为0.48、0.63、0.58和0.42、0.60、0.55。随着留叶数增多,成熟期全株的氮、磷、钾素分配率随之提高,而单株摘叶的氮、磷、钾素分配率随之下降。紧凑型品种在成熟期全株中的氮、磷、钾素分配率较伞型品种分别提高了7.33、5.45和4.36个百分点。  【结论】  木薯留叶数越多,摘叶的数量和干物质量越少。随着留叶数增加,木薯产量随之增加,成熟期全株的养分积累量和块根、叶片的养分分配率随之提高。木薯摘叶后,叶片光合产物优先满足地上部生长。在本试验条件下,块根膨大期适宜的留叶数为81～90片,有利于确保木薯产量和养分积累利用。     

Nitrogen and Potassium Fertilization Responses of Potato (Solanum tuberosum) cv. Spunta

A potato field experiment was conducted for 2 consecutive years to determine the effects of nitrogen (N) and potassium (K) fertilization rates on the yield and quality of potato cv. Spunta cultivated on soil low in N and K. A 3?×?4 complete factorial experiment was used with three rates of nitrogen (330, 495, and 660 kg N ha^–1) and four rates of potassium (112, 225, 450, and 675 kg K₂Ο ha^–1). An additional treatment without fertilization was used as the control. On soils low in N and K, potatoes showed low yield response to K fertilizer. The greatest tuber yields for both years were achieved at 495 kg N ha^–1 and 112 kg K₂O ha^–1 (29.81 t ha^–1) and 225 kg ha^–1 (27.13 t ha^–1), respectively. Differences in mean fresh weight due to treatment application were not significant. Application of 495 kg N ha^–1 significantly reduced harvest index (the ratio of tuber dry weight to the total dry weight at harvest) compared to 330 kg N ha^–1, but at 660 kg N ha^–1 harvest index achieved the greatest significant value. Potassium fertilization had no significant influence on harvest index. Nitrogen rates positively influenced the number of tubers. The addition of 450 kg K₂O ha^–1 significantly enhanced the number of tubers compared to the lower K rates, and the number was significantly decreased by the application of 675 kg K₂O ha^–1. Tuber dry-matter concentration was significantly promoted by N fertilization in both cultivation years, but it was negatively affected by K fertilization in the first year of cultivation. There was no change in tuber N with N application, but N application strongly increased nitrate (NO₃) concentration, which fluctuated between 360 and 1382 mg kg^–1 wet mass. Tuber NO₃ was negatively correlated with tuber yield, indicating that high levels of NO₃ in tubers can adversely affect yield. Tuber response to K fertilization was not in accordance with the rate of applied nutrient.     

Growth and Nutrient Absorption of Cape Gooseberry (Physalis Peruviana L.) in Soilless Culture

Cape gooseberry (Physalis peruviana L.) is a solanaceous plant. The growth and time-course of nutrient accumulation of the plant and its partitioning between roots, stems, leaves, and fruits were examined. The study was conducted analyzing two nutrient solutions in soilless culture under greenhouse conditions during two consecutive seasons. The macronutrient contents were analyzed. On average, the yield was 8.9 t·ha^?1. Growth of the plant until 90 d after transplanting obeys an exponential function of time and the relative growth rate for this period was determined. Nitrogen (N) was the element that showed the highest concentration, corresponding to leaves (4.67%), followed by potassium (K) in stems (4.46%). The highest accumulations of N, phosphorous (P), calcium (Ca), and magnesium (Mg) were found in leaves and of K in the stems. Potassium showed the highest nutrient accumulation (29 g·plant^?1) and the highest specific uptake rate.     

Phytoextraction of Cd and Pb and physiological effects in potato plants (Solanum tuberosum var. Spunta): importance of root temperature.

Three consecutive years of field experiments were carried out to investigate the effect of different root-zone temperatures, induced by the application of mulches, on the concentration and accumulation of Cd and Pb and on bioindicators (chlorophylls, catalase, peroxidase and cell wall fractions) in different organs of potato plants (roots, tubers, stems, and leaflets). Four different plastic covers were employed (T1, transparent polyethylene; T2, white polyethylene; T3, white and black coextruded polyethylene, and T4, black polyethylene), using uncovered plants as the control (T0). The different treatments had a significant effect on the mean root-zone temperatures (T0 = 16 degrees C, T1 = 20 degrees C, T2 = 23 degrees C, T3 = 27 degrees C, and T4 = 30 degrees C) and induced significantly different responses in the Cd and Pb concentrations and phytoaccumulation, with T2 (23 degrees C) and T3 (27 degrees C) giving high concentrations of Cd in the roots and low concentrations in other organs. In relation to Pb, T2 and T3 reached higher levels in the tubers and lower levels in the roots, stems, and leaves. In terms of phytoaccumulation, the roots and tubers were the most effective organs for Cd and Pb. On the other hand, the highest values of peroxidase and catalase activities were obtained for T3. In addition, most of the carbohydrate fractions in both the roots and the tubers were highest for T3. Meanwhile, the lowest pigment values were registered for T1 (20 degrees C). For phytoremediation, it is necessary to ascertain the relevance and control of the thermal regime of the soil to optimize the phytoextraction of pollutant elements (Cd and Pb).     

EXPERIMENTAL LEACHING OF MACRONUTRIENTS FROM BRASSICA NAPUS L. INCREASES WITH LEAF AGE AND GROWTH STAGE

It was the aim of the present study to determine the mobile nutrient content in leaves and pods of oilseed rape in relation to leaf age and growth stage and to develop an instrument to estimate the possible significance for interpretation of plant analytical data. From older leaves an increasing amount of sulfur (S), potassium (K), magnesium (Mg), calcium (Ca), and phosphorus (P) was leached, while no N was extracted after 24 h of leaching. In younger leaves the potential for nutrient leaching was below 10% for all investigated nutrients while in older leaves this value increased to 58% for S, 28% for P, 21% for Mg, 18% for Ca and 16% for K. Generally the potential for nutrient leaching from leaves and pods increased with growth stage. Until BBCH 83 nutrient leaching from pods was very low with less than 5% for the investigated elements, except S, but increased with further ripening drastically.     

超高产夏玉米干物质与氮、磷、钾养分积累与分配特点

探讨超高产夏玉米品种整株干物质与氮、磷、钾养分积累分配特点,为制定高产栽培管理措施提供依据.本文在大田条件下,以登海661(DH661)和郑单958(ZD958)为试验材料,比较研究了超高产夏玉米干物质与氮、磷、钾养分积累分配特点.结果表明,超高产夏玉米DH661在成熟期内整株干物质及氮、磷、钾积累量分别为33475.53 kg/hm2、369.76 kg/hm2、117.85 kg/hm2、285.78 kg/hm2,均显著高于ZD958,较ZD958分别高15.82％、23.72％、32.17％、21.89％.超高产夏玉米DH661的干物质和氮、磷、钾养分在叶片和茎秆中的分配比例均低于ZD958,而籽粒和根系中的分配比例高于ZD958,因而具有较高的养分收获指数与偏生产力.整个生育期内,DH661各器官的养分吸收速率均显著高于ZD958,具有较高的养分吸收效率;茎、叶及根系的氮、磷、钾养分吸收速率在灌浆期前保持较高水平,之后下降较快,而籽粒的氮、磷、钾养分吸收速率于灌浆期后增加较快.吐丝期后,DH661仍能吸收积累较多的养分,因此吐丝后适当追肥对于超高产夏玉米灌浆期养分充足供应至关重要.     

密云水库北京集水区油松水源保护林主要养分元素积累与分配研究

对密云水库北京集水区油松水源保护林主要养分元素积累与分配的研究结果表明:29年生油松林的生物量为92 627 kg/hm².油松林不同器官中各养分元素的含量差异较大,在叶、枝和干中各养分元素的含量顺序分别为N(K)>K(N、Ca)>Ca(K)>Mg(P)>P(Mg).根系中的养分元素随着根系直径的增加呈各养分元素的含量降低.油松林生态系统5种养分元素的贮存量为695.17 kg/hm².若以各养分元素在油松林生态系统中的贮存量来计,则N的贮存量最大,P的最小,不同养分元素贮存量的顺序N>Ca>K>Mg>P.油松林生态系统对N元素的富集能力最强,不同器官中各养分元素的富集系数排序均为N>P>K>Ca>Mg.油松林每积累1 t干物质需N、P、K、Ca和Mg等5种养分元素共计7.51 kg.     

Potato growth and nutrient diagnosis as affected by systemic pesticide and physiological growth stage

Abstract

Growth and chemical composition of crop plants may be subject to alteration by systemic compounds employed for pest control. A field study was implemented to examine the effects of aldicarb on growth, chemical composition, and nutrient diagnosis of a potato crop at various growth stages. Aldicarb use resulted in increased dry matter production of leaves, stems, and tubers, and final fresh tuber weight during the second year of the study. Higher tuber yields were likely due to greater photosynthetic capacity because the increase in leaf dry matter production with time was greater in the aldicarb treatment than in control. Leaf nutrition was not influenced by aldicarb; however, leaf nutrient content varied greatly with growth stage. Similar nutrient status evaluations were generated by DRIS, regardless of pesticide treatment or growth stage. DRIS was able to diagnose nutrient limitations as early as tuber initiation     

Effects of selenium treatments on potato (Solanum tuberosum L.) growth and concentrations of soluble sugars and starch

The effect of selenium (Se) treatments on potato growth and Se, soluble sugar, and starch accumulation was investigated. Potato plants were cultivated in quartz sand without or with sodium selenate (0, 0.075, 0.3 mg Se kg(-1) sand). In young potato plants, Se treatment resulted in higher starch concentrations in upper leaves. The tuber yield of Se-treated potato plants was higher and composed of relatively few but large tubers. At harvest, the starch concentration in tubers did not differ significantly between treatments. The higher Se addition (0.3 mg Se kg(-1)) may have delayed the aging of stolons and roots, which was observed as high concentrations of soluble sugar and starch. Together with the earlier results showing elevated starch concentration in Se-treated lettuce, the findings of this research justify the conclusion that Se has positive effects also on potato carbohydrate accumulation and possibly on yield formation.