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1.
The long-term effect of organic recycling on some aspects of quality in a lowland rice soil of an Indian plateau region was studied. The experiment was set up at the agricultural experimental farm of the Indian Statistical Institute, Giridih, Bihar, India. Two rice cultivars, and treatments with four organic supplements (cowdung manure, Leuceana leaves, decomposed farm residue and Sesbania ), chemical fertilizers (urea, superphosphate and muriate of potash) and no input were arranged in a factorial randomized block design. Organic supplements improved soil quality parameters such as water holding capacity, total organic C, microbial biomass C, urease and acid phosphatase activities of soils in comparison to chemical fertilizers and no input. Among the organic supplements, cowdung manure gave significantly higher organic C (1.39%), microbial biomass C (276.46 μg g−1 dry soil), urease activity (32.79 and 21.22 μg urea hydrolized g−1 dry soil h−1 at 37 °C by the buffer and non-buffer method, respectively) and acid phosphatase activity (1.99 μmol p-nitrophenol released g−1 dry soil h−1 at 37 °C) than the others. The conversion of organic C into biomass C (2.46%) was highest in Leuceana -treated soil.  相似文献   

2.
Two wheat lines (TL3 and TL5) derived from selection for Cu tolerance among wheat – Aegilops sharonensis hybrids were compared when grown as hydroponics at zero (control), 10−6 and 10−5  m CuSO4. The morphometric measurements showed that the line TL5 with a more inhibited root system under 10−6  m CuSO4 had a less inhibited shoot growth under 10−5  m CuSO4 as compared to TL3. The decreased maximum efficiency of photosystem II and the more pronounced trend towards increased catalase activity suggested that despite the better shoot growth, the leaves of TL5 were more functionally injured. The increased content of carotenoids at excess Cu and the higher peroxidase and catalase activities of TL3 in control plants might contribute to its better stress tolerance. While no significant changes in enzyme activities were found at 10−6  m Cu, at 10−5  m the activities tended to increase. Although the close values of free phenolics concentrations in control plants, at Cu excess their content was higher in TL5 compared to TL3. The free phenolics content in roots at 10−6  m Cu decreased, and although higher at 10−5  m Cu, it remained below the control in TL3, and above the control in TL5. From the obtained results TL3 emerged to be more tolerant to excess Cu than TL5.  相似文献   

3.
Five cultivars of sorghum viz: PU-7, Sarokartuho, Bagdar, Redjanpur and Potobar 4–8 were studied for their growth, N uptake and utilization efficiency at 5 mM N in solution culture. These cultivars differed significantly in their dry matter accumulation and relative growth rate of shoot. Differences in shoot/root of the cultivars were also notable. Markedly different mean N intake rate among the sorghum cultivars was 108 μmol g−1 root dry wt. hr−1 in Bagdar and 53 μmol g−1 root dry wt. hr−1 in PU-7 and Redjanpur. Both relative accumulation rate of N and efficiency of biomass accumulation per unit N absorbed also differed appreciably among the cultivars.  相似文献   

4.
A field experiment was conducted at the Indian Agricultural Research Institute, New Delhi to study the growth and yield of wheat as influenced by the concentrations of ammonium-N and nitrate-N in soil. A series of ammonium and nitrate nitrogen concentrations in soil on a time frame was developed by treating prilled urea with nitrification inhibitors DCD or neem cake as well as by changing the dose and time of N application. The study revealed that number of tillers m-1 as well as ears m-1 row length were significantly positively correlated with ammonium-N concentration at 15 and 30 DAS and nitrate-N concentration at 30 and 45 DAS. Number of grains ear-1 was significantly positively correlated with ammonium-N at 30, 45 and 60 DAS and nitrate-N at 45 and 60 DAS. Ultimately grain yield in wheat was significantly positively correlated with ammonium-N concentration at 15 and 30 DAS and nitrate-N concentration at 30, 45 and 60 DAS. The response between grain yield and concentrations of both ammonium and nitrate forms of N was quadratic. The optimum concentration of ammonium-N in soil for maximum grain yield gradually decreased with the age of the crop from 54.6 to 63.6 μg g-1 at 15 DAS to 22.7 to 26 μg g-1 at 30 DAS. In the case of nitrate-N its optimum concentration for maximum grain yield increased with age of the crop from 25.1 to 30 μg g-1 at 15 DAS to 31.6 to 34 at 45 DAS and it decreased thereafter.  相似文献   

5.
A Rapid Method for Measuring Freezing Resistance in Crop Plants   总被引：3，自引：0，他引：3  
The objective of this study was to develop a technique based on chlorophyll fluorescence to assess freezing injury and resistance of leaves. Optimization was done with faba bean leaves and applicability to other crops was examined at winter and spring with types of barley, oats, rape and faba beans. Selected leaves from young hardened beans were subjected to standardized freezing tests with different minimum temperatures ( T min) and fluorescence was monitored. After a dark period basic fluorescence ( F O was induced by 0.2 μmol m−2 s−1 pulsed red light and maximum fluorescence ( F m) was assayed at different light intensities. 1500 μmol m−2 s−1 rendered to give the maximum possible output of Fm and best differentiation of differently damaged leaves by F n= F m - F O. Leaf temperature during measurement and during a short storage (± 2 h) should be kept at about 0°C to avoid biases between differently damaged leaves. The measuring spot on the leaf must be standardized since fluorescence response differed at the tip and base of a leaflet, but not between the two leaflets of a faba bean leaf. The applicability of F rr (ratio of F r of stressed to unstressed leaves) as a measure of resistance was demonstrated by comparison of winter hardiness of cultivars with freezing resistance calculated from the relationship of F vr and the T min used in freezing tests.  相似文献   

6.
Seedling growth and ion content of Pakistani bread wheat cultivars was assessed in solution culture in the absence and presence of NaCl (100 and 200 mol m−3) to determine whether seedling traits could be used in breeding programs for salt-tolerance. Growth was recorded as seedling fresh weight, and the shoot and leaves analysed for major inorganic ions. Plants subjected to salt stress excluded Na+ and Cl− ions from the shoot to varying extents. Exclusion preferentially maintained lower Na+ and Cl− levels in the apical tissue, as the leaf to leaf gradient in Na+ and Cl− became steeper as the external salinity increased, although there were significant differences between cultivars. Correlation analysis on individual plants indicated that excluding Na+ at low salinity, and Na+ and Cl− at high salinity, were correlated significantly with growth performance, although it was clear that other factors were also involved. The relationship of tolerance to ion exclusion was stronger when the data were examined on an individual plant basis than when related to pooled cultivar data or to the cultivar rank order derived from field trials, probably due to large variations in Na+, and to a lesser extent, Cl− transport in supposedly homozygous cultivars.  相似文献   

7.
Two barley crops, one fertilized with 120 kg N ha−1 (B120) and the other without nitrogen fertilization (BO), were cultivated for the second year on the same plot. In 1981 the growth and nitrogen content of the whole plant, above- and below-ground parts were measured by sampling every second week. Production was calculated as the difference between annual maximum and minimum amounts of biomass found above- and below-ground. Nitrogen uptake was estimated as the sum of the peak amounts of nitrogen present in the roots and shoots. The amount and concentration of nitrogen in partly decomposed plant debris in the soil was estimated simultaneously with the biomass.
Total net production in B120 was 1004 g m−2 of which the roots constituted 16%. The unfertilized barley produced 558 g m−2 of which 23% were produced below-ground. The maximum amount of living roots found in B120 was 160 g ash-free dry mass m−2 and 128 g m−2 in BO.
In the fertilized treatment 15 g N m−2 (21% in roots) was taken up by the plant, compared to 5.8 g N m−2 (28% in roots) in the unfertilized crop.  相似文献   

8.
The effect of polyethylene glycol (PEG) osmopriming on plant emergence in laboratory at optimal (25 °C) and suboptimal (18 and 14 °C) temperatures was assessed in two cultivars of sweet sorghum differing in kernel colour: Brandes, light-coloured, and Roce, dark-coloured. Sterilized sand or non-sterilized soil were used as substrates. PEG osmopriming enhanced seedling emergence in sand. In soil, the light-seeded cultivar produced seedlings only at optimum temperature, whereas the unprimed dark-seeded cultivar performed well as in sand at all temperatures and reduced dramatically its germination capacity at suboptimal temperatures following priming treatment. These results might be related to the presence of tannins in the seed coat. Seed tannin contents of 80 and 590 mg 100 g−1 seed fresh weight (FW) were determined in Brandes and Roce respectively. These amounts consistently reduced after PEG osmopriming, especially in Roce (217.5 mg 100 g−1 seed FW). The decline in tannin content in Roce, because of osmopriming, might explain the poor emergence of this cultivar in soil. These results suggest the opportunity of using high-tannin cultivars of sweet sorghum in the field, which may better growth in this environment when early sowings are required.  相似文献   

9.
Determination of optimal N-fertilization rates, NOR , for crop production that minimize risk of environmental degradation require accurate application of a response model. Several models are available to describe crop yield response to N fertilization. The objective of this work was to compare the relative accuracy of a quadratic, f(N Q), a modified Mitscherlich, and tanh( N ) models on 48 data sets. Data were collected from a Tara silt loam (fine-silty, mixed, frigid Pachic Udic Haploboroll) over a 6-year period using two maize ( Zea mays L.) hybrids and four tillage treatments, mouldboard plough, chisel plough, ridge tillage and no-tillage. In about one-third of the cases, all models performed about equally well. Generally, the tanh( N ) and modified Mitscherlich models gave better fit between N rate and grain yield data. The NOR, ranged from about 140 to 170 kg ha−1 for the modified Mitscherlich model, 136 to 184 kg ha−1 for the tanh( N) function, and 124 to 173 kg ha−1 using the f(N Q) model. Estimated grain yields at these rates ranged between 6.58 ± 1.30 to 7.59 ± 1.69 Mg ha−1 for the 90-day Minnesota maturity rated (MR) hybrid and between 7.52 ± 2.40 to 8.72 ± 1.70 Mg ha−1 for the 95-day MR hybrid.  相似文献   

10.
The effects of planting date and plant density on potassium (K) and magnesium (Mg) uptake and harvest by Brussels sprouts ( Brassica oleracea var. gemmifera ) were studied in field experiments. Crop potassium concentration generally decreased towards harvest, but the pattern in potassium concentration during crop growth differed between planting dates. Plant density in the range of 2.7–4.4 plants m−2 had no effect on crop potassium concentration. The amount of potassium in the crop at harvest decreased with a delay in planting, but was not influenced by plant density. Mainly depending on the planting date, around 100–200 kg potassium ha−1, or approximately 40–50 % of the potassium in the crop at harvest, is removed from the field with the product. Averaged over treatments and years, potassium concentration in the (fresh) product was 5.2 kg ton−1. The amount of magnesium in the crop at harvest decreased with a delay in planting. Depending on the planting date, uptake at harvest was 10–17 kg magnesium ha−1. Plant density had no effect on this amount. On average per ton (fresh) product, 0.20 kg of magnesium was removed from the field.  相似文献   

11.
Spring cut Italian ryegrass was harvested at two different stages of maturity: lake vegetative (EARLY) and flowering (LATE). The wilted forage was round baled and then ensiled by wrapping in plastic film. EARLY harvest reduced dry matter (DM) yield significantly as compared to LATE (5.6 vs. 10.5 t ha−1; P < 0.01). However, forage quality both before and after ensiling was better for EARLY with higher crude protein (CP) and non-structural carbohydrates content and a lower amount of cell walls (NDF). Higher pH and the fermentation characteristics confirmed the poor quality of LATE silage, having higher content of butyrate, propionate and acid detergent insoluble nitrogen and a lower concentration of lactic acid.
Dry matter intake of EARLY silage by sheep (average 65.0 ± 7.3 kg LW) fed solely forage ad libitum was 37 % higher than LATE (1386 vs. 1011 g DM day−1; P < 0.05) due to its better palatability and digestibility. In vivo DM digestibility of EARLY silage was 76.1 % while it decreased to 58.2 % for LATE silage. Estimated metabolizable energy content of EARLY silage (11.5 MJ kg−1 DM) was 29 % higher than LATE (8.9 MJ kg−1 DM) resulting as similar to the reference value of a high quality perennial ryegrass silage. The forage conservation system of ensiled round bales is effective and recommended when spring cut Italian ryegrass is harvested at an early stage of maturity.  相似文献   

12.
X. L. An  X. H. Li  X. J. Xiong  Y. M. Yan    Y. Z. Zhang    L. Y. Gao    A. L.Wang    K. Wang    F. J. Zeller    S. L. K. Hsam 《Plant Breeding》2009,128(1):41-45
A new x-type HMW glutenin subunit, designated as 1Dx1.6t from Aegilops tauschii was identified and characterized by SDS-PAGE and MALDI-TOF-MS. This subunit is located between 1Dx2 and 1Dx1.5t and possesses a molecular mass ( M r) of 88565.8 Da. Its complete coding sequence was amplified via allele-specific PCR (AS-PCR), and the amplified product was cloned and sequenced. The authenticity of the cloned 1Dx1.6 t gene was confirmed by successful expression of its open reading frame in Escherichia coli. The molecular characterization of 1Dx1.6 t gene showed that its coding region consisted of 2541 bp encoding a polypeptide of 845 amino acid residues. Sequence comparison to previously characterized 1Dx1.5t subunit which is related to good dough quality of bread wheat indicated that the 1Dx1.6t subunit displayed high homology, but possesses 14 residue substitutions and a nonapeptide insertion. A total of 12 single-nucleotide polymorphisms (1 per 212 bp) was identified in the 1Dx1.6 t allele (11 in repetitive domain and 1 in the C-terminal domain), which could facilitate the design of AS-PCR markers.  相似文献   

13.
Influence of light quantity on growth and biological nitrogen fixation of white clover ( Trifolium repens L.)
The influence of photon irradiance (Ep; 100 to 500 μmol m−2 s−1) and of the photoperiod (16 or 11 h) on growth and nitrogenase activity of nodulated white clover plants was studied in growth chambers at two nitrate levels (1.0 and 7.5 mM NO3−).
Total dry mass production, the root proportion and nitrogenase activity increased with increasing Ep and photoperiod. Nitrogenase activity generally increased proportionally to root mass. Only at low Ep (100 μmol m−2 s−1) and under a short photoperiod (11 h) was the specific nitrogenase activity per unit root mass reduced. An abrupt change in Ep led to a rapid and parallel change in nitrogenase activity and relative growth rate.
A higher NO3− concentration in the nutrient solution (7.5 mM) led to a marked decrease in specific nitrogenase activity, but increased growth between 200 and 500 μmol m−2 s−1 during early development only. At 100 μmol m−2 s−1, there was no growth response to nitrate, although its effect on nitrogenase activity was more marked than at a higher Ep.
The results show that with changing light quantity, biological nitrogen fixation of white clover adapts to the existing demand for nitrogen and does not limit growth except during early development, even when light supply is low.  相似文献   

14.
Soil and climatic conditions in Newfoundland are on the margins of agricultural capability, and almost all feed grain is imported. The overall objective of this work was to develop guidelines for the production of barley in Newfoundland, with the goal of establishing modern cropping recommendations. We conducted a 4-year study near St. John's to examine the effect of seeding rate and topdress ammonium nitrate (N) fertilization rate on Chapais six-row barley ( Hordeum vulgare L.) yield components and grain yield. Increasing seeding rate from 200 to 380 seeds m–2 did not alter grain yield in any year. Increasing topdress fertilization from 0 to 60 kg N ha–1 increased spike density m–2 at harvest, resulting in linear increases in grain yield in all years. Highest N rates had greatest lodging in two years. Based on our results, agronomic recommendations for eastern Newfoundland now include barley seeding rates of 250 ± 50 seeds m–2, with topdress applications up to at least 30 kg N ha–1.  相似文献   

15.
Throughout the world, lodging in cereals causes great losses in yield each year. A two year field study was conducted to determine the relationship of morphological traits to lodging resistance in spring wheat ( Triticum aestivum L.) breeding lines and to find easily measurable traits related to lodging resistance. A set of 15 breeding lines, representing a wide range of combinations of plant height and lodging resistance, was evaluated.
During the first year, 29 morphological traits were measured at two growth stages and correlated with the lodging score. Higher correlations were found for traits measured at anthesis (DC 65) than for traits measured at maturity (DC 92); most of the fresh weight traits correlated better to lodging resistance than did the corresponding dry matter parameters. During the second year the six traits of plant height, stem length, stem diameter, ear weight, stem weight and stem weight per cm were measured at anthesis and correlated with the lodging score.
From the pooled data of four experiments, significant correlations between the lodging score and single morphological traits were found for stem diameter and stem weight per cm. Thicker stems and heavier stems (mg per cm) were indicative for better lodging resistance. Stem diameter and stem weight cm−1 explained 48.5 % and 49.7 %, respectively, of the phenotypic variation in lodging resistance. Multiple linear regression equations indicated that 77.2 % of the variation in lodging resistance was based on stem weight cm−1 and on the weight of the ear.  相似文献   

16.
Solar tracking has been described in several agronomic and wild species, yet variation within a given species has not been reported. To address that issue, photoperiod leaflet reorientation in response to vectorial light was measured in three alfalfa ( Medicago sativa L.) germplasm pools selected from the cultivar Ladak 65. Dark-leaf germplasm responded to all photosynthetic photon flux densities (PPFD) (100 to 700 μmol/m2/s) with no detectable lag period. Following a 24-h dark treatment only high PPFD (600 to 700μmol/m2/s) elicited reorientation. Pale-leaf germplasm responded to intermediate (300 to 400 μmol/m2/s) and high PPFD in a similar manner; however, the low (100-125μmol/m2/s) PPFD treatment had little effect on reorientation. The 24-h dark treatment decreased reorientation at all PPFD. Small-leaf germplasm responded equally to all PPFD and was not affected by the 24-h dark treatment. The results suggest that available energy levels may influence the reorientation response. Carbonyl cyanide m -chlorophenylhydrazone, an inhibitor of photophosphorylation, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea, an inhibitor of non-cyclic photosynthetic electron transport, reduced reorientation only in the pale-leaf type. These results suggest that stored energy reserves were adequate to maintain leaflet reorientation in the absence of photosynthesis in all but the pale-leaf germplasm. In that germplasm photosynthetically generated energy may be required to support reorientation.  相似文献   

17.
Seed meal amendments rich in glucosinolates are of interest for soil pest and disease control. The Ethiopian mustard ( Brassica carinata A. Braun) line N2-6215, with very high levels of seed glucosinolates (160 μmol/g), was developed from the line C-101 (116 μmol / g) following mutagenesis. The objective of this research was to study the inheritance of very high seed glucosinolate content. Plants of N2-6215 were reciprocally crossed with plants of the line C-101. The F1, F2, and BC1F1 plant generations were evaluated in two environments and seeds from individual plants were analysed for total glucosinolate content. The very high glucosinolate content in N2-6215 seeds was largely subject to maternal control. No cytoplasmic effects were detected. The trait was found to be oligogenic and determined by at least two or three genes. The estimates of broad-sense heritability were 0.45 and 0.58 in both environments, whereas the estimates of narrow-sense heritability were 0.35 and 0.50. The moderate heritability and oligogenic control of the trait suggest the feasibility of breeding for increased seed glucosinolate content in Ethiopian mustard.  相似文献   

18.
Four bread wheat cultivars were studied at two salinity levels. Tobari 66 had the lowest uptake of Na+ and Cl−, and the highest K+/Na+ ratio; Pato had the highest uptake of these ions and Lyallpur 73 was intermediate. Intervarietal differences were greater at higher salinity, suggesting that they were not caused by variation at the Kna1 locus. There were significant differences between inbred lines for Na+, particularly in Blue Silver, suggesting the possibility of selecting genotypes with enhanced tolerance from within existing cultivars. Pato, Tobari 66 and their reciprocal F1 hybrids were further evaluated at four salinity levels. The hybrids exhibited similar relative grain yield to Tobari, with better Na+ and Cl− exclusion and higher K+/Na+ ratios than Pato. Overall, Tobari had the highest absolute yield under salinity, and the hybrids were closer to Tobari than to Pato. Tiller and grain numbers, 100-grain weight and yield were more affected by salinity than were height, spike length and spikelet number. We conclude that intervarietal variation for salt tolerance in wheat is controlled by genes which could be transferred to sensitive genotypes to improve their tolerance, and that the K+/Na+ ratio of the youngest leaf could be used to screen for salt tolerance.  相似文献   

19.
Influence Of Tillage On Soil Aeration   总被引：2，自引：0，他引：2  
Air- porosity of soil can be altered by tillage. Therefore, it plays a significant role in protecting plants against deficient aeration during critical periods of their life cycle. The effect of five tillage treatments (mouldboard, cultivator, rotary tiller, wedge and zero tillage) and three mulch treatments (paddy straw, rice husk and bare) on the soil oxygen diffusion rate (ODR) during the various growth phases of peanut crop ( Arachis Hypogaea L.) were investigated on a lateritic sandy loam soil (utilsol). These experiments were conducted for two consecutive seasons. ODR values were higher in tilled plots. Among tillage treatments, the highest ODR was recorded under mouldboard (60.51 × 10-8 g cm-2 min-1), followed closely by cultivator (57.65 × 10-8g cm-2 min-1), and it was lowest under rotary tiller (46.29 × 10-8 g cm-2 min-1). During the later growth stages and also in lower soil depths, the differences between the values of ODR narrowed down. Among mulch treatments, plots with rice husk (53.98 × 10-8 g cm-2 min-1), had the higher ODR values. Bulk density was lower, whereas total and aeration porosity were higher, under mouldboard and cultivator. Soil temperatures were also higher under mouldboard and cultivator tilled plots.  相似文献   

20.
The pattern of free NH4+ accumulation and its metabolism was studied during the growth and development of field-grown wheat cv. HD 2204 at two applied N levels viz. 30 and 120 kg ha−1. The study was confined to the 3rd, 5th and flag leaf blades and the developing ears, borne on the main shoot, during their ontogeny. The NH4+ levels were considerably lower in young leaves and increased sharply as the leaves senesced when the activity of glutamine synthetase (GS) declined. In contrast to GS, glutamate dehydrogenase (GDH) remained active even during senescence. Concentrations of protein, free amino acid and total reduced N declined with age in the leaves. An assessment of free NH4+ pool, free amino acid content and the activity of GS and GDH in the floral parts revealed that glumes, awns and grains also were active sites of NH4+ turnover. Higher applied N level not only increased leaf and grain N concentration but also led to higher free NH4+ levels in leaves and in developing ears. Presence of NH4+ in the entrapped transpirate revealed that NH4+ is released from both leaves and ears during senescence.  相似文献   

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