首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 257 毫秒
1.
Abstract

Bell pepper (Capsicum annuum cv. Urfa Isoto) and cucumber (Cucumis sativus cv. Beith Alpha F1) were grown in pots containing field soil to investigate the effects of supplementary potassium phosphate applied to the root zone of salt‐stressed plants. Treatments were (1) control: soil alone (C); (2) salt treatment: C plus 3.5 g NaCl kg?1 soil (C + S); and (3) supplementary potassium phosphate: C + S plus supplementary 136 or 272 mg KH2PO4 kg?1 soil (C + S + KP). Plants grown in saline treatment produced less dry matter, fruit yield, and chlorophyll than those in the control. Supplementary 136 or 272 mg KH2PO4 kg?1 soil resulted in increases in dry matter, fruit yield, and chlorophyll concentrations compared to salt‐stressed (C + S) treatment. Membrane permeability in leaf cells (as assessed by electrolyte leakage from leaves) was impaired by NaCl application. Supplementary KH2PO4 reduced electrolyte leakage especially at the higher rate. Sodium (Na) concentration in plant tissues increased in leaves and roots in the NaCl treatment. Concentrations of potassium (K) and Phosphorus (P) in leaves were lowered in salt treatment and almost fully restored by supplementary KH2PO4 at 272 mg kg?1 soil. These results clearly show that supplementary KH2PO4 can partly mitigate the adverse effects of high salinity on both fruit yield and whole plant biomass in pepper and cucumber plants.  相似文献   

2.
ABSTRACT

Influences of nickel (Ni) concentrations in the nutrient solution on yield, quality, and nitrogen (N) metabolism of cucumber plants (Cucumis sativus cv ‘RS189’ and ‘Vikima’) were evaluated when plants were grown either with urea or nitrate as the sole N source. The cucumber plants were treated with two N sources, urea and nitrate as sodium nitrate (NaNO3) at 200 mg L?1, and three concentrations of Ni as nickel sulfate (NiSO4·6H2O; 0, 0.5, and 1 mg L?1). Treatments were arranged in a randomized block design with six replicates. The highest concentration of Ni in the leaves (1.2 mg kg?1 Dwt) was observed in the urea-fed plants at 1 mg L?1 Ni concentration. Additions of Ni up to 0.5 mg L?1 had no effect on the fruit Ni concentration in the both urea and nitrate-fed plants. Yield significantly (p < 0.05) increased with the Ni supplements from 0 to 0.5 mg L?1 (10 and 15% in ‘RS189’ and ‘Vikima’, respectively), but decreased when 1 mg L?1 Ni applied to the solutions in urea-fed plants. Nitrate-fed plants had a higher percentage of total soluble solids compare to those urea-fed plants. Nitrate concentrations of the fruits in urea-fed plants in both cultivars were reduced by approximately 50% compared to those nitrate-fed plants. The reduction of nitrate concentration in the fruits became more pronounced as the Ni concentration increased in the solution. The rate of photosynthesis (Pn) increased with the increase of the Ni concentration in the solution with urea-fed plants. Both N concentration and nitrate reductase (NR) activity of young leaves were higher in urea-fed plants at 0.5 mg l?1 Ni concentration. Ni supplements enhanced the growth and yield of urea-fed plants by increasing Pn, N concentration and NR activity. It can be concluded that Ni supplements (0.5 mg l?1) improve yield, quality, and NR activity in urea-fed cucumber plants.  相似文献   

3.
Boron (B) deficiency hampers cotton (Gossypium hirsutum L.) growth and productivity globally, especially in calcareous soils. The crop is known as a heavy feeder of B; however, its reported plant analysis diagnostic norms for B-deficiency diagnosis vary drastically. In a 2-year field experiment on a B-deficient [hydrochloric acid (HCl)–extractable 0.47 mg B kg?1], calcareous, Typic Haplocambid, we studied the impact of soil-applied B on cotton (cv. CIM-473) growth, productivity, plant tissue B concentration, and seed oil composition. Boron was applied at 0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 kg B ha?1, as borax (Na2B4O7·10H2O), in a randomized complete block design with four replications, along with recommended rates of nitrogen (N), phosphorus (P), potassium (K), and zinc (Zn). Boron use improved crop growth, decreased fruit shedding, and increased boll weight, leading to seed cotton yield increases up to 14.7% (P < 0.05). Improved B nutrition of plants also enhanced seed oil content (P < 0.05) and increased seed protein content (P < 0.05). Fiber quality was not affected. Fertilizer B use was highly cost-effective, with a value–cost ratio of 12.3:1 at 1 kg B ha?1. Fertilizer B requirement for near-maximum (95% of maximum) seed cotton yield was 1.1 kg B ha?1 and HCl-extractable soil B requirement for was 0.52 kg ha?1. Leaf tissue B requirement varied with leaf age as well as with plant age. In 30-day plants (i.e., at squaring), B-deficiency diagnosis critical level was 45.0 mg kg?1 in recently matured leaves and 38.0 mg kg?1 in youngest open leaves; at 60 days old (i.e., at flowering), critical concentration was 55.0 mg kg?1 in mature leaves and 43.0 mg kg?1 in youngest leaves. With advancement in plant age critical B concentration decreased in both leaf tissues; that is, in 90-day-old plants (i.e., at boll formation) it was 43.0 mg kg?1 in mature leaves and 35.0 mg kg?1 in the youngest leaves. As critical concentration range was narrower in youngest leaves (i.e., 35–43 mg kg?1) compared with mature leaves (i.e., 43–55 mg kg?1), B concentration in youngest leaves is considered a better indicator for deficiency diagnosis.  相似文献   

4.
An experiment was conducted to determine if salinity stress alters the response and tolerance of soybean to defoliation. Four soybean [Glycine max(L.) Merr.] cultivars (‘Tachiutaka,’ ‘Tousan 69,’ ‘Dare’ and ‘Enrei’) in a growth chamber were exposed to two salinity treatments (0 and 40 mM NaCl) and two defoliation treatments (with and without defoliation). The interactive effects of salinity stress and defoliation on growth rate, leaf expansion, photosynthetic gas exchange, and sodium (Na+) accumulation were determined. The decrease in growth rate resulting from defoliation was more pronounced in plants grown under salinity stress than in those grown without the stress. Without salinity stress, defoliated plants of all four cultivars had leaf-expansion similar rates to those of the undefoliated ones, but the photosynthetic rates of their remaining leaves were higher than those of undefoliated plants. However, with salinity stress, defoliated ‘Tachiutaka’ and ‘Tousa 69’ had lower leaf expansion and photosynthetic rates than undefoliated plants. For cultivars ‘Dare’ and ‘Enrei,’ the defoliated plants had leaf-expansion rates similar to undefoliated ones, but the photosynthetic rate of the remaining leaves did not increase. Except for cultivar ‘Dare,’ defoliated plants grown under salinity stress had higher Na+ accumulation in leaves than undefoliated ones, and this result may be related to slow leaf expansion and photosynthesis. Salinity stress negatively affects soybean response and tolerance of defoliation, and the effects varied according to the salt tolerance of the cultivar.  相似文献   

5.
Brassica alboglabra plants were first grown aeroponically with full nutrients under full sunlight with average midday photosynthetic photon flux density (PPFD) of 1200 μmol m?2 s?1. Thirty days after transplanting, plants were respectively, subjected to 10 days of average midday PPFD of 1200 (control, L1), 600 (L2) and 300 μmol m?2 s?1 (L3). Productivity, photosynthetic CO2 assimilation and stomatal conductance were significantly lower in low-light (L2 and L3) plants than in high-light (L1) plants. Low light plants had the highest nitrate (NO3?) accumulation in the petioles. Low light also had an inverse effect total reduced N content. After different light treatments, all plants were re-exposed to another 10 days of full sunlight. Low-light plants demonstrated their ability to recover their photosynthetic rate, enhance productivity and reduce the NO3? concentration. These results have led to the recommendation of not harvesting this popular vegetable during or immediately after cloudy weather conditions.  相似文献   

6.
Commercial cultivation of Bt cotton produced higher boll load which led to stiff inter-original competition for photosynthates, resulting in early cessation of growth (premature senescence) due to more availability of sink and less sources. To overcome this problem, field experiment was conducted during 2011 and 2012 using five treatments of plant growth manipulation viz. no fruiting branch removal (F1), removal of first fruiting branch (F2), removal of first and second fruiting branch (F3), removal of all squares from first fruiting branch (F4), removal of all squares from first and second fruiting branches (F5), and three potassium (K) application rates viz. 50 kg ha?1 (K1), 100 kg ha?1 (K2), and 150 kg ha?1 (K3). More nodes above white flower were recorded in F5, followed by F3, while minimum were recorded in F1. Among potassium levels, maximum nodes above white flower were recorded in K3 followed by K2 and K1 during both years of study. Plant height recorded at physiological cutout stage or at maturity stage showed that plants gained more height with removal of all squares from first tosecond fruiting branches with higher potassium dose. Leaf K increased with increasing applied potassium and also with square/branch removal. So early removal of squares/fruiting branches along with higher potassium dose helped in delaying canopy senescence in Bt cotton.  相似文献   

7.
The short-term effectiveness of three application rates of vivianite [(Fe3(PO4)2·8H2O)] in preventing lime-induced iron (Fe) chlorosis in Eureka lemon (Citrus lemon L.) cuttings grafted on sour orange (Citrus aurantium L.) was investigated and compared with the commonly applied iron ethylenediaminedi(o-hydroxyphenylacetic) acid (FeEDDHA). Treatments were suspension of vivianite injected into the soil at three rates (0.5, 1.0, and 2.0 g kg?1 soil), 417 mg FeEDDHA per plant, and untreated plants. Chlorophyll concentration index (CCI) of the youngest fully expanded leaves was estimated. Growth vigor and leaf Fe concentration were also measured. Vivianite, particularly at the greatest two rates, resulted in significantly greater growth vigor and leaf Fe concentration and exhibited greater CCI values compared to untreated plants similar to FeEDDHA. However, if excessive growth vigor is not favorable, the 0.5 g vivianite kg?1 soil is recommended for farmers. Vivianite is a potential environmentally safe alternative to the expensive FeEDDHA to prevent Fe chlorosis in lemon.  相似文献   

8.
《Journal of plant nutrition》2013,36(7):1367-1382
Abstract

The effect of supplementary potassium nitrate (KNO3) on growth and yield of bell pepper (Capsicum annum cv. 11B 14) plants grown in containers under high root‐zone salinity was investigated. Treatments were (1) control, soil only and (2) high salt treatment, as for control plus 3.5 g NaCl kg?1 soil. Above treatments were combined with or without either 0.5 or 1 g supplementary KNO3 kg?1 soil. Plants grown at high NaCl had significantly less dry matter, fruit yield, and chlorophyll than those in the control treatment. Supplementing the high salt soil with 0.5 and 1 g KNO3 kg?1 increased plant dry matter, fruit yield, and chlorophyll concentrations as compared to high salt treatment. Membrane permeability increased significantly with high NaCl application, but less so when supplementary KNO3 was applied. High NaCl resulted in plants with very leaky root systems as measured by high K efflux; rate of leakage was reduced by supplementary KNO3. These data suggest that NaCl status affect root membrane integrity. Sodium (Na) concentration in plant tissues increased in leaves and roots in the elevated NaCl treatment as compared to control treatment. Concentrations of K and N in leaves were significantly lower in the high salt treatment than in the control. For the high salt treatment, supplementing the soil with KNO3 at 1 g kg?1 resulted in K and N levels similar to those of the control. These results support the view that supplementary KNO3 can overcome the effects of high salinity on fruit yield and whole plant biomass in pepper plants.  相似文献   

9.
Sulfur (S) is an essential nutrient in crop plants and one of the components of amino acids (AAs) and proteins. Studies about sulfur efficiency on soybean cultivars [Glycine max (L) Merril] adapted to the tropical and subtropical conditions are still incipient. In Brazil, one experiment under greenhouse conditions evaluated the S-efficiency from eight soybean cultivars. The plants cultivated in a Typic Quartzipsamment received two S rates (0 and 80 mg kg?1). The grain yield (GY), shoot dry weight (SDW), and the relative yield (RY) had influence from the S rates. The cultivars BRS 295RR and BRS 360RR were the most efficient in using the S application. The number of pods per plant (NPP), photosynthetic rate (A), nitrate reductase (N-NO2?), and chlorophyll significantly increased with de 80 mg kg?1 of S. By contrast, the internal concentration of carbon dioxide (CO2) (Ci) was reduced. Similarly, there were increases in the concentration of nitrogen (N), phosphorus (P), magnesium (Mg), and N:S ratio in the leaves and grain, but the K increased only in the leaves. Comparing the cultivars, only the N concentration in the leaves and the Mg in the grain had non-significant differences.  相似文献   

10.
为了研究黄淮海平原不同秸秆还田方式和施氮类型对夏玉米农田生态系统土壤呼吸的影响,于2010年6—10月,采用LI-COR-6400-09土壤气室连接红外线气体分析仪(IRGA)对玉米农田行间掩埋秸秆区的土壤呼吸作用进行了连续测定。结果表明,常规施肥下,玉米生育期内秸秆行间掩埋处理(ISFR)的平均土壤呼吸速率显著高于秸秆移除(NSFR)和秸秆覆盖(SFR)处理(P<0.05)。秸秆行间掩埋配合施用化学氮肥处理中,配施50.4 kg(N).hm 2处理(ISF3)的平均土壤呼吸速率为(178.85±46.60)mg(C).m 2.h 1,显著高于配施33.6 kg(N).hm 2处理(ISF2)的(124.11±23.18)mg(C).m 2.h 1(P<0.05)。秸秆行间掩埋配合施用鸡粪处理中,鸡粪施用量为33.6kg(N).hm 2(ISOM2)处理的平均土壤呼吸速率为(208.08±31.54)mg(C).m 2.h 1,施用16.8 kg(N).hm 2(ISOM1)和50.4 kg(N).hm 2(ISOM3)处理的为(135.07±21.97)mg(C).m 2.h 1、(171.43±43.31)mg(C).m 2.h 1,相比ISOM2处理,ISOM1和ISOM3处理的平均土壤呼吸速率降低了35.09%和17.61%。ISOM2处理玉米季CO2排放累积量为499.39 g(C).m 2,显著高于ISF2处理的297.86 g(C).m 2。秸秆行间掩埋配合施用化学氮肥对土壤呼吸速率的影响小于配合施用鸡粪的影响,配合施用16%总氮的鸡粪,即33.6 kg(N).hm 2时C/N比最适宜土壤微生物的代谢活动。  相似文献   

11.
The effect of increasing chloride content in nutrient solution on nutrient composition in root environment, interaction of nutrients in leaves and yield of greenhouse tomato cv. ‘Grace F1’ grown in rockwool were searched. In Experiment I (2004–2005) the levels of 15, 30, 60, and 90 mg Cl·L?1 but in Experiment II (2006) 30, 60, 90 and 120 mg Cl·L?1 of nutrient solution were tested. The sources of chloride were water (9.6–10.7 mg Cl·L?1) and calcium chloride (CaCl2·2H2O) but the rest of nutrients and sodium in all treatments were on the same levels. It was found that increasing content of chloride from 15 to 60 mg Cl·L?1 enhanced the total and marketable fruit yield. Within the range of 60 to 90 mg Cl·L?1 the yield was on the optimum level but the content of 120 mg Cl·L?1 declined it. Increasing chloride content in the nutrient solutions was reflected in rising of chlorine content in leaves. The concentration of chloride above 60 mg C·L?1 reduced the content of nitrogen but above 90 mg C·L?1 declined the content of calcium, sulfur and zinc in leaves. The antagonism between Cl:N, Cl:Ca: Cl:S and Cl:Zn was appeared. More variable interaction were between Cl:K and Cl:B. At the low levels of chloride, from 15 to 60 mg Cl·L?1, potassium and boron content were decreased but at the higher ones, from 90 to 120 mg·L?1, these nutrients had increasing course. It was not found out the effect of chloride contents on macro and microelement contents in nutrient solution emitted from drippers however their content upraising in root medium (rockwool). The highest increase was found out for Na 95.1 and 64.9 % (Exp. I and II - respectively), next for Ca (76.0, 70.1 %), Cu (62.5 and 71.0 %), Cl (43.6, 24.4), B (33.3, 21.0 %), N-NO3 (30.4, 49.6 %), Zn (29.5, 32.8 %), S-SO4 (25.9, 25.5 %), K (24.5, 24.1 %), Fe (19.8, 19.2 %), Mn (17.5, 21.3 %) and Mg (14.9, 11.7). Advantageous effect of chloride on tomato yield justified the need to introduce for the practice adequate chlorine nutrition, and recommend to maintain 60 to 90 mg Cl·L?1 in nutrient solution. The best yield appeared when content of chlorine in leaves (8th or 9th leaf from the top) was in the range 0.48-0.60 % of Cl in d. m.  相似文献   

12.
The effects of NaCl and magnesium levels (Mg2+) on the physiological response of sunflower were investigated. Plants were grown for 54 days in hydroponic culture with NaCl (100 mM) or without NaCl and four concentrations of Mg2+: 0, 0.4, 1.0 and 5.0 mM. At the end of the vegetative growing cycle of sunflower, salt stress reduced leaf area development by 51% and dry matter accumulation by 37% as compared to non saline-treated plants; at this stage, considering the percent reduction of partitioned plant dry matter, roots (42%) and leaves (35%) showed to be more salt-sensitive than stem. Growth reduction was related to the drop in net CO2 assimilation rate and stomatal conductance, which started declining later during the vegetative growth period when leaf ion concentration started increasing. The investigated genotype was unable to exclude ions and significant amounts of Cl? (about 1700 μmol g?1 DW) and lesser Na+ (700 μmol g?1 DW) accumulated in the leaves. The decline in net CO2 assimilation was well correlated to the increase in leaf Cl? concentration (r2 = 0.71) and not to leaf Na+ concentration (r2 = 0.33). The results suggest that, though sunflower develops an endogenous protection system by which it redistributes this ions in the whole plant, with more ions accumulating in roots and older leaves, growth reduction may be attributed to specific toxic effects of Cl? on photosynthetic functionality. In both saline and non saline conditions, little or no significant differences in growth parameters of plants exposed to a range from 0.4 to 5 mM of Mg2+ were observed. Whereas, its deficiency caused a drastic reduction of dry matter accumulation up to 90%, due to progressive decline in CO2 assimilation rate and chlorophyll content, with imbalances in Ca2+, Mg2+ and K+.  相似文献   

13.
The ability of buckwheat (Fagopyrum esculentum) roots to acquire phosphorus (P) was characterized by investigating P uptake, morphological features, and chemical changes in the rhizosphere. Over a range of nutrient solution P concentrations (5–500 μmol · L?1), maximum shoot growth was achieved with a P supply between 5 and 100 μmol · L?1. Root weight and root length, as well as length and frequency of root hairs, were higher at low P levels. Root surface and the root surface/shoot dry weight ratio reached high values. Though P uptake rates were only moderate (0.15 pmol · cm?1 root · sec?1), shoot P concentrations were high (1.8% of dry weight with 100 μM P) predominantly being inorganic (80%). Phosphorus efficiency was characterized by a high specific absorption rate (810 mmol P · kg?1 root dry wt · d?1) rather than by an efficient utilization for dry weight production. Root exudates of low-P plants had lower pH values than exudates of high-P plants and increased the solubility of FePO4 and MnO2 to a greater extent. Amounts of exuded organic acids and phenolics were low and could not account for the observed solubilization of FePO4 and MnO2. Enhanced hydrolysis of glucose-6-phosphate by exudates from low-P plants was due to an increased “soluble” acid phosphatase activity, and root surface phosphatase activity was also slightly enhanced with P deficiency. In the rhizosphere soil of buckwheat, some depletion of organic P forms was observed, and in pot trials with quartz sand, buckwheat utilized glucose- 6-phosphate as a P source at the same rate as inorganic P.  相似文献   

14.
A drip fertigation system should use low-cost phosphorus fertilizer available in small markets to smallholders such as especially Brazilian tomato growers. A study was conducted in an unheated greenhouse to establish an optimum rate of single superphosphate (SS) to formulate an aqueous solution that can be applied to tomato plants through a low-pressure drip irrigation system. Five rates of SS [18% phosphorus pentoxide (P2O5)] 0, 25, 50, 100, and 200 g·plant?1, were evaluated in a randomized block design with four replications. Each rate was subdivided into 15 equal parts. Each part was dissolved in water (210 mL for each plant) and the mixture left to settle for 24 hours. The supernatant was applied by drip irrigation every week for 15 weeks. The tomato plants were grown in 9 dm3 plastic bags containing fertilized substrate in an unheated greenhouse. The leaf contents of nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), copper (Cu), and zinc (Zn) were not affected by the treatments. The highest phosphorus (P), manganese (Mn), and iron (Fe) leaf contents were obtained from plants fertilized with SS at 79; 0; 0 g·plant?1, respectively. The marketable tomato fruit yield, measured up to 123 days after transplanting, increased with the increasing SS up to 54 g·plant?1, resulting in a yield of 6.16 kg·plant?1, corresponding to 10.3 kg·m?2. A settled aqueous solution of SS (54 g·210 mL?1 of water) can be applied weekly to tomato plant through a low-pressure drip irrigation system during the plant cycle.  相似文献   

15.
水氮互作对温室黄瓜光合特征与产量的影响   总被引：1，自引：0，他引：1  
在日光温室内研究了水氮互作对黄瓜叶片不同生育期光合特征与产量的影响,分析了各生育期黄瓜光合速率与产量的关系。结果表明:光合速率、蒸腾速率在盛瓜期最高,而水分利用效率则在初瓜期达最高。习惯灌水条件下,施氮量的增加有助于光合速率和蒸腾速率的提高,其中以灌水7470m3·hm-2、施氮1200kg·hm-2时(W1N1200)最高,但与灌水5190m3·hm-2、施氮600kg·hm-2时(W2N600)无显著差异;叶片水分利用效率以减量灌水、减施氮50%处理(W2N600)为最高,是习惯水氮处理(W1N1200)的1.08倍,对照(W1N0)的1.24倍。水氮互作对黄瓜产量及产量构成因素具有显著影响,其中以减量灌水30%左右、减施氮50%的处理组合(W2N600)最优,黄瓜产量最高可达17.06×104kg·hm-2。黄瓜的光合速率与产量、瓜条数、单果重之间呈二次曲线关系,其中盛瓜期的拟合方程最好。  相似文献   

16.
《Journal of plant nutrition》2013,36(6):1023-1039
Abstract

A field experiment was conducted to assess the effectiveness of fruiting positions along sympodia under varying levels and sources of potassium (K) fertilizer on field-grown cotton in an arid environment. Treatments consisted of four rates of K (0, 62.5, 125.0, 250.0 kg K ha? 1) and two types of K (K2SO4 and KCl). Cotton cultivar S-12 (Gossypium hirsutum L.) was used as a test crop. Plant mapping data showed that the total number of fruiting positions, number of intact fruit on sympodia/monopodia, and percent of bolls per position on sympodia differed greatly under different doses of K fertilizer. The percentage of fruit retention was markedly improved under increasing doses of K fertilizer as compared with the K-unfertilized treatment. The percent survival of harvestable bolls for the first five positions along sympodia at the end of the season was 30%, 25%, 18%, 13%, and 8%, respectively. Potassium fertilization stimulated cotton crop in lengthening sympodial branches and retaining more fruit on the first three positions and also at the bottom of the plant during the early reproductive phase. The fruiting pattern was 2–3 and 6–7 d vertical and horizontal fruiting interval, respectively.  相似文献   

17.
To determine the effect of boron (B) deficiency on biomass, reproductive yield, metabolism, and alterations in seed reserves of chickpea (Cicer arietinum L.) cv. ‘13.G‐256,’ plants were grown in refined sand until maturity at deficient (0.033 mg L?1) and adequate (0.33 mg L?1) B, supplied as boric acid (H3BO3). Boron‐deficient plants exhibited visible deficiency symptoms in addition to reduced number of pods and seeds, resulting in lowered biomass and economic yield. Boron deficiency lowered the concentration of B in leaves and seeds, photosynthetic pigments (leaves), Hill reaction activity, starch (in leaves and seeds), and proteins and protein N (in seeds), whereas phenols, sugars (in leaves and seeds), and nonprotein N (in seeds) were elevated. Specific activity of peroxidase (POX) increased in leaves and pod wall and decreased in seeds, while activity of acid phosphate and ribonuclease were stimulated in leaves, seeds, and pod wall in B‐deficient chickpea.  相似文献   

18.
ABSTRACT

Zinc (Zn) deficiency is a global nutritional problem in crops grown in calcareous soils. However, plant analysis criteria, a good tool for interpreting crop Zn requirement, is scarcely reported in literature for onion (Allium cepa L.). In a greenhouse experiment, Zn requirement, critical concentrations in diagnostic parts and genotypic variation were assessed using four onion cultivars (‘Swat-1’, ‘Phulkara,’ ‘Sariab Red,’ and ‘Chilton-89’) grown in a Zn-deficient (AB-DTPA extractable, 0.44 Zn mg kg?1), calcareous soil of Gujranwala series (Typic Hapludalf). Five rates of Zn, ranging from 0 to 16 mg Zn kg?1 soil, were applied as zinc sulphate (ZnSO4·7H2O) along with adequate basal fertilization of nitrogen (N), phosphorus (P), potassium (K), and boron (B). Four onion seedlings were transplanted in each pot. Whole shoots of two plants and recently matured leaves of other two plants were sampled. Zinc application significantly increased dry bulb yield and maximum yield was produced with 8 mg Zn kg?1. Application of higher rates did not improve yield further. The cultivars differed significantly in Zn efficiency and cv. ‘Swat-1’ was most Zn-efficient. Fertilizer requirement for near-maximum dry bulb yield was 2.5 mg Zn kg?1. Plant tissue critical Zn concentrations were 30 mg kg?1 in young whole shoots, 25 mg kg?1 in matured leaves, 16 mg kg?1 in tops and 14 mg Zn kg?1 in bulb. Zinc content in mature bulb also appeared to be a good indicator of soil Zn availability status.  相似文献   

19.
In herbaceous plants grown in controlled environmental conditions nitrate (NO3?) uptake increases during the day and decreases in the night. The aim of this work was to measure NO3? uptake rates along the day-night cycle, in rose (Rosa hybrida L.) plants grown under controlled environmental conditions. Two independent experiments were conducted inside a growth chamber at 20 ºC and 25 ºC, using rose mini-plants cv. Texas, grown in a hydroponic nutrient film technique (NFT) set-up with at 3.0 mol m?3 NO3? concentration. Dry matter and nitrogen (N) accumulation were registered during growth and NO3? uptake rates were measured during a day-night cycle, using 15N as 15NO3?. In both experiments the hourly estimated N-NO3? accumulation rates are near to the measured uptake rates of 15NO3? and nitrate uptake decrease during the day and increase in the night, in contrast with the herbaceous plants. Results are discussed on the basis of N plant demand and carbohydrates availability.  相似文献   

20.
植物叶片特征与光合性能的关系   总被引：5，自引：1，他引：4  
以相同生境下生长的5种叶片特征(叶色和厚薄等)不同的植物[珊瑚树(Viburnum odoratissimum)、银杏(Ginkgo Biloba)、桑树(Morus alba)、紫叶酢浆草(Oxalis triangularis cv.Purpurea)和紫叶橡皮树(Ficus elasticacv.Decora Burgundyi)]为材料,于晴天选择其植株上东南朝向且生长一致并具代表性的当年生成长叶,采用Li-Cor 6400便携式光合测定系统、调制叶绿素荧光成像系统(IMAGING-PAM M-Series)及双通道PAM-100测量系统(Dual-PAM-100)和常规方法研究了其叶片特征、光合性能及相互间的关系。结果表明,不同植物的叶片特征和光合性能指标均存在显著或极显著差异。比叶干重[35~215 g(DW).m-2]间的差异大于比叶鲜重[0.28~1.04 kg(FW).m-2]。桑树和珊瑚树叶的叶绿体色素含量[叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素总量(Chl)和类胡萝卜素(Xc)]较高,银杏叶和紫叶橡皮树叶居中,紫叶酢浆草叶最低;紫叶酢浆草叶的花青素(Ant)含量最高[0.122 mg.g-1(FW)和0.488 mg.g-1(DW)],其他植物较低且差异较小;紫叶酢浆草叶的Chla/Chlb(6.27)、桑树的Chl/Xc(9.97)、桑树叶的Chl/Ant(43.81)和珊瑚树叶的Xc/Ant(7.17)最高,紫叶酢浆草叶的Chl/Ant(0.49)和Xc/Ant(2.46)最低。气孔导度、蒸腾速率、胞间CO2浓度和净光合速率(Pn)均为桑树>银杏>紫叶酢浆草>珊瑚树>紫叶橡皮树。桑树和珊瑚树叶的PSII实际光合效率[Y(II)]最高,但PS II处非调节性能量耗散的量子产量也最高;银杏Y(II)叶较低,但能抵御强光的照射。桑树、紫色酢浆草和紫色橡皮树叶的PSI光合效率[Y(I)]极高,但桑树和紫色橡皮树PSI的光保护较弱,紫色酢浆草则很强。相关分析显示,Ant和Xc对强光下Pn无显著影响,Pn受气孔特征和叶绿素含量的正调控,Y(II)依赖于叶绿体色素含量(尤其是Chla),Y(I)与Chl/Xc呈正向关系;气孔开放和叶绿素含量可负调控光合机构的光保护和正调控光损伤,Xc则相反。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号