Calciumgehalte in Früchten von Paprika,Bohne, Quitte und Hagebutte im Verlauf des Fruchtwachstums

Calcium content in fruits of paprika, bean, quince and hip during fruit growth The Ca content and the Ca translocation into the fruits during their growth was determined in paprika and bean under controlled conditions (nutrient solution, growth room) and in quince and hip (Rosa rugosa Thumb.) under field conditions. Compared to leaves the Ca content in the fruits is very low in all 4 species and declines further during their growth. The K content, however, is similar in the leaves and in the fruits of all 4 species and remains nearly constant during fruit growth. The low Ca content of the fruits cannot directly be related to the cation exchange capacity (CEC) as there are no differences in the CEC between leaves and fruits. The generally low Ca content of the fruits and its decline during fruit growth is causally related in all 4 plant species to the low rate of Ca translocation compared to the rate of dry matter translocation into the fruits. There are, however, distinct differences between the 4 plant species in the course of the ratio Ca/dry matter translocation into the fruits: In paprika the Ca translocation into the fruits strongly declines during fruit growth and in bean the Ca translocation practically ceases with the onset of seed growth. In quince under field conditions the Ca translocation into the fruits rapidly declines at later stages and finally a translocation of Ca out of the fruit takes place (decrease in the amount of Ca/fruit). Only in hip the Ca translocation into the fruits remains constant during fruit growth. There is, however, a distinctly different distribution of Ca to the various parts within the hip fruits. The decline in Ca translocation during fruit growth can be explained in paprika and bean with a shift in water influx from the xylem (rich in Ca) to the phloem at the stage of high rates of dry matter influx into the fruit. In quince and hip, however, additional mechanisms (alternating water flux in the xylem, CEC) seem to be involved in the regulation of the Ca content of these fruits.     

长期干旱环境对柑橘生长及养分吸收和相关生理的影响

为了揭示长期干旱环境下柑橘生长及养分吸收和相关生理响应的特点,探索长期干旱对柑橘的不良影响,以红橘(Citrus tangerina Hort.cv."Chuanju")为材料,以有灌溉条件为对照,在贵州北盘江喀斯特河谷长期自然干旱环境下连续4年观察和取样分析测定红橘的物候期,新梢和果实生长发育状况,叶片寿命,果实及叶片N、P、K、Ca、Mg、Fe、Cu、Zn、B等元素的含量,分析果实生理病害与干旱及元素含量的关系;测定与抗旱相关的形态、组织解剖及生理特征,研究红橘对长期干旱的生理响应与适应长期干旱的关系。结果表明:长期干旱环境下红橘新梢生长、开花及生理落果物候期明显推迟,果实成熟期提早,叶寿命缩短;新梢短而细且数量及叶片数减少,枯死严重;叶片革质化程度加重,叶片变小变厚,新梢叶缺N、Zn、Fe、B等症状明显;果实的鲜重、干物质质量、水分含量、种子数、果汁含量减少,春梢叶中N、P、K、Ca、Mg、Fe、Cu、Zn、B及果实的N、P、Ca、Fe、B素的含量明显降低,果皮流胶和汁胞粒化程度加重,品质下降;叶片的栅栏组织增厚,海绵组织变薄,组织紧密度和气孔密度增大,气孔变小,组织疏松度降低;在周年中叶片的脯氨酸及可溶性糖含量增加,临界水分饱和亏增大,失水速率及相对含水量和叶水势变小,Pn及Tr明显降低,夏季的WUE明显提高。红橘适应长期抗旱的能力强。在长期干旱的环境中红橘的生长节律、植株及叶片形态和寿命、叶片厚度及组织结构、气孔密度与大小、叶片的临界水分饱和亏、失水速率、相对含水量、叶水势及脯氨酸和可溶性糖含量、光合速率与蒸腾速率都发生了有利于抵御长期干旱的特异性变化。长期干旱是导致红橘树冠枝梢大量枯死、果实发育缓慢变小、种子败育、果皮流胶及汁胞粒化和果实及叶片中营养元素含量减少的主要原因。     

Der Einfluß von Dicyandiamid und N-Serve in Verbindung mit Ammoniumsulfat als N-Dünger auf die Nitrat- und Oxalsäuregehalte von Spinat (Spinacia oleracea)

Occurence of boron deficiency in Citrus aurantium L. (Bitter orange) at the Caspian Sea (Iran) In a Bitter orange plantation near the Caspian sea over a period of two years different amounts of boron were applied either as borax to the soil or as Solubor to the leaves. Without boron supply the fruits were misshapen, had a rough and thick peel and often brown spots in the pulp. Supply of 5 – 20 g B per tree prevented the occurence of these symptoms and increased both the fruit size and the proportion of the pulp. Without boron supply on fresh weight basis the proportion of pulp/peel was 1 : 1, 6 – 2, 0 as compared to 1 : 0, 6 – 0, 7 with boron supply. The effect of the different boron supply was well reflected in the boron content of the leaves and especially of the fruits. Borax increased the boron content of the plants more than Solubor. Conzidering both the low content of available boron in most of the soils of the Citrus area near the Caspian sea and the special ecological conditions (high pH values and low water content of the soils during fruit development) boron deficiency can be expected. The results of the experiment with Bitter oranges confirm that boron fertilizing is an important factor for plant production in this area.     

Significance of fruit transpiration on calcium nutrition in developing apricot fruit

The first objective of this study was to search for a possible correlation between accumulation of calcium (Ca), potassium (K), and magnesium (Mg) and fruit transpiration in developing apricot (Prunus armeniaca L.) fruit. Secondly, the work aimed to determine the significance of transpirational flux on Ca nutrition. We hypothesized that if the fruit transpiration is the determining factor of Ca accumulation (phloem‐immobile element) then the import of Ca would be suppressed by restriction of fruit water loss, while the import of phloem‐mobile nutrients (i.e., K and Mg) would not be. To test this hypothesis, the seasonal changes of transpiration and of Ca, K, and Mg concentration/accumulation were assessed in fruits left to naturally transpire or under restricted transpiration (bagged fruits). Fruit transpiration was measured on detached fruits using a portable gas‐exchange equipment (ADC‐LCA4, ADC BioScientific Ltd, Hoddesdon, England). Results demonstrated that 83% of total fruit Ca content was gained within the first 4 weeks after fruit‐set, and that Ca import ceased concomitantly to a reduction of transpiration. In spite of the limitation of fruit transpiration, Ca entered the nontranspiring fruits, and its concentration was about 45% of that in control fruits suggesting that other factor(s) operated for Ca accumulation. This study provides the evidence that fruit transpiration accounted for 55% of total Ca that entered a fruit. We conclude that optimal soil Ca availability and apportioning to the fruit during the early 4 weeks of growth are essential to sustain the fruit demand of this nutrient and that some cultural practices (e.g., summer pruning, irrigation) should be tested as possible tools to improve fruit Ca nutrition via increasing fruit transpiration.     

Cycling of nitrogen and potassium between shoot and roots in maize as affected by shoot and root growth

In nitrate-fed plants cycling of nitrogen (N) and potassium (K) may serve several functions including supply of the roots with nutrients needed for growth, signalling of the growth-related shoot demand for nutrients to the roots, and removal of excess K from the shoot. In the present study, cycling and recycling of N and K were estimated in plants showing different rates of shoot and root growth. To induce these variations in growth, the plants were cultured with the same optimal nutrient supply but with the root zone temperature (RZT) at 12°C or 24°C. Additionally at both RZT, the plants were grown with their shoot base including apical shoot meristem at high or low temperature (SBT). Decreasing the RZT to 12°C drastically diminished root growth and accumulation of N and K in the roots. Cycling of N and K were less reduced by low RZT. At both RZT, N and K cycling were markedly reduced at low in comparison to high SBT although root growth was not affected by the SBT. Obviously, N and K cycling from shoot to roots were more affected by shoot growth than by the growth related demand of the roots for nutrients. At both RZT, N and K cycling exceeded accumulation in the roots. It was estimated that at least 20—33% of the N, and 24—51% of the K translocated from the roots to the shoot in the xylem is not directly derived from root uptake but from cycling. Plant culture at low shoot base temperature (SBT) drastically diminished shoot growth, and the accumulation of N and K in the shoot to less than 50% of the values measured in plants grown at high SBT. The low SBT-induced decrease of N accumulation in the shoot, at both RZT was associated with a reduction of K circulation and recirculation rates to less than 50% of those found in plants grown at high SBT. These findings are in accordance with the suggested role of K⁺ for charge balance facilitating the transport of NO₃^— in the xylem and disposal of the negatively charged products of NO₃^— assimilation from shoot to roots in the phloem. In plants cultured at low SBT, net uptake and translocation rates of N and K were diminished to less than 50% of those measured in plants grown at high SBT. This repression was associated with reduced rates of N and K cycling from the shoot to the roots. Obviously, low rates of N and K cycling from the shoot to the roots are not necessarily signals to increase uptake in the roots. It is suggested that for plants adequately supplied with N, high rates of N cycling and recycling might be the consequence of an apparent lack in control of phloem loading of amino acids in the leaves.     

Boron‐and‐salt interactions in wheat are affected by boron supply

Plants in arid or semiarid areas often experience simultaneous salt and boron (B) stress. Interactive effects on stress responses have been clearly established, but results are inconsistent and variably indicate antagonistic or synergistic interactions even within the same plant species. In this study, five differently B‐ and salt‐resistant wheat genotypes were grown hydroponically at low and high B supply. The effect of increasing NaCl salinity on plant growth, boron uptake rates, shoot B concentrations, and transpiration was determined under both B regimes. The interactive effect of salt and B was different under low and high B supply. Boron‐uptake rates were reduced with increasing salt concentration only under high B supply, and reductions correlated significantly with decreases in leaf area and shoot B concentrations. Under low B supply, however, salt‐induced effects on B‐uptake rates were variable and not significantly correlated with leaf‐area reductions. These results suggest that under high B supply, when B uptake is predominantly passive by diffusion or channel‐mediated via aquaporins, transpiration‐driven water flow is the dominant factor for B accumulation in arial plant parts. Under low B supply, when a significant portion of B can be taken up via active pathways, transpiration is not the decisive factor for B accumulation. Under these conditions, the salt sensitivity of a genotype is a modifying factor of salt–B interactions, because salt‐induced growth inhibition can result in a concentration effect, offset the reduction of B‐uptake rates, and result in increased shoot B concentrations. Contradictory reports on the nature of salt–B interactions might in part be related to low levels of B supply chosen as control treatments and concomittant differences in predominant B‐uptake pathways.     

猪血蛋白水解物对盆栽樱桃番茄生长和品质的影响

  【目的】  研究外源喷施不同浓度猪血蛋白水解物 (PP)对樱桃番茄植株生长和品质的影响,以期为高产优质樱桃番茄生产提供理论参考。  【方法】  以樱桃番茄品种“盆栽红”为试验材料,采用基质栽培,设置3个PP浓度:0 g/L (CK)、1 g/L (PP1)、2 g/L (PP2),在开花期进行叶面喷施,整个生育期共喷施6次。樱桃番茄在第三穗果实完全成熟后收获,分析外源PP对樱桃番茄植株生长、光合作用、养分吸收以及果实品质的影响。  【结果】  PP1和PP2处理不同程度地增加了番茄地上部、根部以及果实中氮、磷、钾含量,显著提高了叶片叶绿素含量、净光合速率 (Pn)、蒸腾速率 (Tr)和气孔导度 (Gs),植株地上部鲜重比CK处理分别增加了18.2%和40.6%,干重分别增加了42.3%和57.4%,且PP2处理的效果好于PP1处理。与CK处理相比,PP2处理番茄的产量、单果重、横径、纵径和硬度分别增加了37.4%、26.6%、16.3%、10.3%和30.8%,并有效改善了果实色泽,提高了樱桃番茄的外观品质。PP2处理有利于樱桃番茄果实中可溶性糖、可溶性蛋白、抗坏血酸和谷胱甘肽的积累,较CK分别增加了24.2%、25.5%、96.6%和30.9%;番茄果实中的总酚、类黄酮和花色素苷含量分别增加18.7%、33.3%和56.2%,DPPH自由基清除能力和铁还原抗氧化能力分别增加了27.7%和29.4%,显著提高了番茄果实的抗氧化活性。  【结论】  外源喷施2 g/L的猪血蛋白水解物能有效改善番茄植株的养分吸收和光合作用,促进植株生长和番茄品质的提升,是一种提高樱桃番茄产量、改善营养和功能性品质的高效有机措施。     

Einfluß des Calcium-Angebotes auf Wachstumsrate und Calcium-Gehalt von Kartoffelknollen

Effect of calcium supply on growth rate and calcium content of potato tubers. . Using potato plants in water culture with a constant calcium supply to the roots, a study was made of the influence of additional supply of calcium to the tuber surface on growth rate and calcium content of the tubers. Under conditions of high relative humidity around the tubers the calcium nutrition of the tubers was exclusively dependent on the calcium supplied to the tuber surface (?exogenous calcium”?). With a high level of exogenous Ca the growth rate of the tubers was high and the rate of uptake of Ca was proportional to the tuber growth. With a low level of exogenous Ca the growth rate declined to a lower but constant value. In absence of exogenous supply of Ca the growth rate of the tubers declined gradually until growth ceased. Cessation of tuber growth occurred when the Ca content decreased below 0,36 mg Ca per g dry matter for smaller tubers and below 0,14 mg Ca per g dry matter for larger tubers. Severe Ca deficiency in potato tubers causes necrosis at the tuber apex.     

硅对向日葵水分利用效率的影响

以向日葵(Helianthus.annuus.L.cv.G101)为试验材料,研究了硅对营养液培养的向日葵生长和水分利用效率的影响。结果表明,施硅显著增加向日葵的水分利用效率,对向日葵生物量、叶面积的影响不大,却使最大展开叶的SPAD值显著增加;施硅显著降低了向日葵叶片背面的蒸腾速率以及叶片导度,而对叶片正面的蒸腾速率和叶片导度影响不大。同时,施硅向日葵木质部汁液的流速显著降低,体内硅含量增加。表明叶片蒸腾速率、叶片导度、木质部汁液流速的降低是硅提高向日葵水分利用效率的主要原因。     

四季柚生育期叶片和果实中矿质元素含量变化的研究

本研究以四季柚为试材,定期测定果实发育周期内叶片与果实的矿质元素含量,研究四季柚叶片和果实矿质养分需求特征与相关性,为树体营养科学调控,优质高效施肥提供理论依据。结果显示,叶片生长过程中N、 P元素含量呈逐渐下降趋势,K、 Ca、 Mg、 B、 Zn含量呈先增后降趋势,S含量总体保持上升趋势,Fe含量呈现先降后稳再上升趋势,Cu含量总体较稳定,Mn含量呈现出先上升后下降再上升趋势; 果实生长过程中,N、 P、 K、 Ca、 S含量呈下降趋势,Mg含量呈现先升后降的趋势,微量元素中Fe、 Mn元素含量变化幅度较小,B、 Zn、 Cu元素含量变化趋势略有不同。叶片与果实之间矿质元素协同吸收作用较弱,而果实与果皮之间作用较强。研究表明,萌芽前应适当增施氮、 磷肥,6月中旬增施钙肥,7月中旬增施钾肥和镁肥,以及重视微量元素肥料的应用。     

滴灌施肥对大棚西瓜生长、产量及品质的影响

该文从优质高产、高效和节水节肥的三重目标出发,通过大田试验,研究在西北旱区对大棚膜下滴灌施肥条件下不同生育时期水肥组合对西瓜生长、产量、灌溉水分利用效率和果实品质的影响,从而确定西瓜适宜滴灌施肥的水肥用量。试验设置3个灌溉量水平:450 m3/hm2(W1)、900 m3/hm2(W2)、1350 m3/hm2(W3),3个施肥水平:N 81.53 kg/hm2+P2O5 33.43 kg/hm2+K2O 101.09 kg/hm2(F1),N 163.05 kg/hm2+P2O5 66.85 kg/hm2+K2O202.18 kg/hm2(F2),N 244.58 kg/hm2+P2O5 100.28 kg/hm2+K2O 303.27 kg/hm2(F3),共9个处理。结果表明:在相同肥料处理条件下,提高灌水量有利于西瓜株高生长,但茎粗减小,发生徒长。F2W2处理能使西瓜叶片叶绿素含量在各个生育期保持较高水平。在西瓜苗期,增加水肥用量的F3W3处理提高了西瓜叶片净光合速率和蒸腾速率,但与F2W2处理差异不显著。坐果期后,F2W2处理的西瓜光合能力较强,获得了较高的产量和水分利用效率,较提高灌水量和施肥量的F3W3处理增产3.6%,灌溉水分利用效率(irrigation water use efficency,iWUE)提高35.73%。在果实品质方面,F2W2处理的西瓜中、边可溶性固形物、可溶性蛋白质和番茄红素等质量分数表现最好,F2W1处理的西瓜可溶性总糖质量分数最高,F3W2处理的西瓜总维生素C质量分数最高,但与F2W2处理差异不显著,且F2W2处理西瓜产生最佳的糖酸比,口感极佳。综合分析表明,F2W2处理的西瓜生长健壮,光合作用强,优质高产,且水分利用效率较高,是利于西北旱作膜下滴灌条件下西瓜生产中适宜的水肥组合。     

辣椒果实钙吸收累积的基因型差异及其生理特征

采用砂培试验研究了 16个辣椒品种对Ca吸收累积的基因型差异和产生差异的生理特征。结果表明 ,在不同供Ca水平下 ,辣椒果实Ca含量的品种间差异明显 ,按供Ca水平与果实Ca累积关系 ,将其分为 :不敏感型 (低Ca时果实Ca降幅 10 % ,高Ca时降幅 >10 % )和增Ca潜力型 (果实Ca随供Ca水平提高而提高 ,增幅 >10 % )三个基因型。比较讨论了三类基因型品种在根系形态特征、叶片蒸腾速率和CAT活性的差异 ,说明辣椒吸收养分及适应能力、蒸腾速率、生物膜的自我保护或修复能力与Ca营养基因型密切相关     

Die Ausnutzung von Wasser sowie Ca und K aus nicht durchwurzelten Dichtezonen zwischen vertikalen Grobporen in Abhängigkeit von der Bodenart

The utilization of water and Ca and K from compacted non-rooted areas between macropores for two soils with different texture In pot experiments with wheat-seedlings and aggregates from a silty Luvisol and a clayic stagni-gleyic Cambisol it was investigated how water, Ca and K are utilized from the dense non-rooted soil between vertical rooted macropores (6, 3, 2 per volume). Root and shoot growth as well as water extraction was increased and the transpiration coefficient decreased for the plants grown in the pot with 3 macropores. During the early stage of growth most Ca was extracted from the pot with short flow distances. The utilization of K in this stage of growth was improved by long flow distances. For the stagni-gleyic Cambisol most dry matter of shoots and roots was produced and most water was extracted from the pot with short flow distances. The transpiration coefficient was smallest in this pot as well.     

Influence of ammonium uptake on bean nutrition

A glasshouse experiment was carried out in order to study the effect of ammonium supply [0 and 1.5 mmol L^‐1 in the nutrient solution, whereas total nitrogen (N) concentration was 9.5 mmol L^‐1] on nutrient uptake, leaves, and xylem sap composition and growth of bean plants in sand culture. Ammonium supply caused higher nitrogen, phosphorus (P), potassium (K), and calcium (Ca) uptake. However, K, Ca, and magnesium (Mg) concentrations in the plants (in xylem sap and leaves) were lower when ammonium was supplied. Plants vegetative growth was higher with ammonium supply than without it, specially after four weeks of cultivation.     

Silicon Improves Water Use Efficiency in Maize Plants

Abstract

The influence of silicon (Si) on water use efficiency (WUE) in maize plants (Zea mays L. cv. Nongda108) was investigated and the results showed that plants treated with 2 mmol L^?1 silicic acid (Si) had 20% higher WUE than that of plants without Si application. The WUE was increased up to 35% when the plants were exposed to water stress and this was accounted for by reductions in leaf transpiration and water flow rate in xylem vessels. To examine the effect of silicon on transpiration, changes in stomata opening were compared between Si-treated and nontreated leaves by measuring transpiration rate and leaf resistance. The results showed that the reduction in transpiration following the application of silicon was largely due to a reduction in transpiration rate through stomata, indicating that silicon influences stomata movement. In xylem sap of plants treated with 2 mmol L^?1 silicic acid, the Si concentration was 200-fold higher, while the Ca concentration which is mainly determined by the transpiration rate, was 2.5-fold lower than that of plants grown without Si. Furthermore, the water flow rate in xylem vessels of plants with and without Si was compared. Flow rate in plants with 2 mmol L^?1 Si was 20% lower than that without Si, which was accounted for by the increased affinity for water in xylem vessels induced by silica deposits. These results demonstrated the role of Si in improving WUE in maize plants.     

Seasonal changes in the major nutrient content of vicia faba plants

Abstract

The changes with time in the growth and total content of N, P, K, Ca, Mg and S in the whole above‐ground part of Vioia faba plants have been studied throughout their development. These bean plants were indeterminate and fruit growth commenced before shoot extension growth ceased. The total dry weight of mature fruit (pods plus beans) exceeded that of the combined leaves and stems at any time. The distribution patterns of the elements fell into two groups; with N, P, K and S the fruit content was large and dominant, while only a modest proportion of the Ca and Mg was in the fruit. There was evidence that some N, P, K and S was re‐distributed from other tissues, but by far the greatest part moved directly into the bean during their expansion stage. These results are discussed in relation to previous reports of the origin of the nutrients of other grain legumes, with particular emphasis on the differences between indeterminate and determinate species.     

磷对不同玉米品种生长、体内磷循环和分配的影响

以杂交玉米蠡玉16和冀单28为供试作物,采用供高磷（250 mol/L）和低磷（5 mol/L）营养液的石英砂培养方法,研究2个玉米品种的各器官干重和磷积累与分配、体内磷在木质部和韧皮部中的循环、流动及磷的吸收和利用效率。结果表明,与供高磷处理相比,低磷处理的2个玉米品种各营养器官的干重、磷含量和木质部中运输的磷量显著降低; 而磷在体内韧皮部的再循环显著增加,并且玉米各部位叶片活化出的磷主要是通过韧皮部循环至根中后,再经过木质部向上部新生叶运输的; 体内光合产物与磷向上部叶的运输是不同步的过程。低磷时,与冀单28相比,蠡玉16的根冠比高010,整株干重和磷含量增加269%和120%,磷吸收和利用效率提高121%和133%,木质部总磷向上部叶运输的比例高306%。说明低磷条件下,磷高效玉米品种生物量大是由于具有较大的根冠比,木质部中更大比例的磷被分配到上部新生叶以及其具有较高的磷吸收和利用效率。     

基质栽培番茄营养液中氮、钾最佳浓度研究

【目的】合理的氮、钾养分供给是提高番茄生长及果实品质的重要措施,本文研究了滴灌营养液中不同的氮、钾养分供给水平对基质栽培番茄生长及果实品质的影响,为优化基质栽培番茄的营养液配方,确定最佳的氮、钾养分浓度,实现养分供给的精量化管理提供科学依据。【方法】以沙∶珍珠岩比例为1∶2配置栽培基质,用于温室中番茄栽培,以番茄‘A20’为试材,进行了水培试验。采用2因素 (氮、钾) 5水平响应面中心复合设计,滴灌营养液中氮浓度的基础值为244 mg/L,试验设计步长为120 mg/L;钾浓度的基础值为313 mg/L,试验设计步长为150 mg/L。调查了番茄叶片叶绿素含量、净光合速率、单株产量、果实可溶性糖含量、可滴定酸含量、糖酸比、维生素C含量和番茄红素含量。【结果】随着滴管液中氮浓度从74 mg/L增加到414 mg/L,番茄产量、叶片叶绿素含量、叶片净光合速率、果实可溶性糖含量、糖酸比、番茄红素含量和果实维生素C含量均呈先增后减的趋势。随着营养液中钾浓度从101 mg/L增加到525 mg/L,果实可溶性糖含量、糖酸比和维生素C含量持续增加,番茄产量、叶绿素含量、净光合速率、番茄红素含量均先增后减。此外,通过建立各指标与氮钾二因子的二次回归方程发现,氮素是叶绿素含量、净光合速率和单株产量的主要影响因子,钾素是果实可溶性糖、可滴定酸、糖酸比、维生素C和番茄红素含量的主要影响因子。氮、钾互作显著影响番茄产量和叶片叶绿素含量;充足的钾营养供给可以促进植株对氮素的吸收与同化,提高叶片叶绿素含量,利于产量提高;适量的氮素供应有利于钾素的吸收与利用,促进产量的进一步提高。采用主成分分析方法对8种配施方案下番茄产量和品质的综合性能进行评价,结果显示营养液中氮、钾浓度分别为N 378 mg/L、K 391 mg/L时为最优配方方案,且番茄叶片净光合速率达到最大值。【结论】在沙子和珍珠岩1∶2 (v∶v) 为基质的番茄无土栽培条件下,滴灌营养液中氮、钾浓度分别为N 378 mg/L和K 391 mg/L时,番茄产量和品质的综合性能达到最优,该方案可在生产实践中为基质栽培番茄营养液精确管理提供一定的借鉴意义。     

交替灌溉对小麦/蚕豆间作系统作物生理生态特性的影响

为探明交替灌溉对小麦/蚕豆间作系统作物生理状况和生长发育的影响,揭示交替灌溉的节水机理,以小麦、蚕豆为材料,采用根箱试验,设置交替灌溉(A)、传统灌溉(T)2种灌溉方式和单作小麦(SW)、单作蚕豆(SF)、小麦间作蚕豆(IWF)3种种植模式,于2008年3—11月在甘肃农业大学网室系统研究了交替灌溉对小麦/蚕豆间作作物叶片水分生理和生物量分配的影响。结果表明:1)与传统灌溉相比,交替灌溉条件下间作小麦、间作蚕豆叶片的叶绿素含量增加,叶片相对含水量、叶水势等水分生理指标减小;不同灌溉方式间小麦间作蚕豆生理特性差异不显著。不同种植模式之间,间作显著增加了小麦和蚕豆叶片的叶绿素含量、叶片相对含水量和叶水势。2)交替灌溉小麦间作蚕豆在保持光合速率基本不变的情况下,蒸腾速率、气孔导度降低,与传统灌溉相比,交替灌溉间作小麦蒸腾速率、气孔导度分别降低了10.99%、20.99%,间作蚕豆分别降低6.66%、11.63%。3)与传统灌溉相比,交替灌溉降低了作物的地上部干物质量,增加了根冠比,其中交替灌溉间作小麦和间作蚕豆的根冠比分别较传统灌溉提高14.47%和18.18%。4)间作有利于作物产量的提高,交替灌溉和常规灌溉间作小麦的收获指数分别较相应单作增加8.68%和2.72%,间作蚕豆分别较相应单作处理增加4.78%和5.23%。可见,对小麦间作蚕豆实行交替灌溉,可以调节光合产物在根冠间的分配,优化根冠比,是一种切实可行的灌溉方式。