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 546 毫秒
1.
Dry matter production of two different spelt (Oberkulmer, Hercule) and wheat varieties (Arina, Iena) were investigated at two different seeding rates (S1 = 200 grains/m2; S2 = 400 grains/m2) and two nitrogen levels (N1 = 80 kg N/ha; N2 = 110 kg N/ha). The plot experiments were carried out at two contrasting locations (Muri: altitude 459 m asl); Oberwallestalden: altitude 1011 m asl) over three years (1988–1990). In addition nitrogen uptake and the photosynthetic rate of flag leaves was measured. Neither growth regulators nor fungicides were applied. The average grain yield of spelt was 25 % lower than that of wheat (32 % at Muri, 18 % at Oberwallestalden). At the reduced seeding rate (S1) grain weight and grain number per ear was increased by 33 % and 31 %, respectively as compared to the normal seeding rate (S2). The increase of the grain weight and the grain number per ear was larger for the two varieties of spelt (47 % and 42 %, respectively) than for the wheat varieties (23 % and 22 %, respectively). The photosynthetic rate of the flag leaf of spelt and wheat was not significantly different, at the two growth stages measured (anthesis, anthesis + 23 days). Nitrogen yield in the above ground biomass (g N/m2) was not significantly different between spelt and wheat, neither at the beginning of stem elongation, nor at anthesis. At anthesis the nitrogen yield at the reduced nitrogen level (N1) was 16 % and 13 % lower than at the higher level (N2) for spelt and wheat respectively. A higher nitrogen efficiency of spelt under low input conditions was not apparent. Therefore it was concluded that under low input conditions, spelt is not more efficient in dry matter production than wheat. By comparing the “husked” yield of spelt (grains + glumes; representing the trade form) with the grain yield of wheat, spelt is higher yielding than wheat but only at marginal areas of cereal production.  相似文献   

2.
以重穗型冬小麦品种兰考矮早八为材料,研究了正常播期(10月10至12日)和适度晚播(10月24至26日)条件下,高(300万株 hm-2)、中(225万株 hm-2)、低(150万株 hm-2)密度对其干物质和氮素积累转运及籽粒产量和品质的影响。结果表明,不同播期条件下,各密度处理开花期和成熟期单茎干物质和氮素积累量均随播种密度降低而增加,适当晚播和中、低密度有利于单茎干物质和氮素积累,尤其是穗部积累量的提高。正常播期和低密度以及晚播和中等密度处理开花前营养器官贮藏干物质向籽粒的转运量和花前贮藏物质对籽粒重的贡献率显著高于其他处理。正常播期和中、低密度处理以及晚播和中、高密度处理显著提高籽粒淀粉和蛋白质的含量与产量以及籽粒产量,使小麦籽粒产量和品质同步提高。在本试验条件下,兰考矮早八兼顾高产和优质的正常播期和晚播的适宜播种密度分别为150~225万株 hm-2和225~300万株 hm-2。  相似文献   

3.
Plant growth and development are influenced by future elevated atmospheric CO2 concentration and increased salinity stress. AM (arbuscular mycorrhiza) symbiosis has been shown to improve plant growth and resistance to environmental stresses. The aim of this study was to investigate the potential role of AM fungus in alleviating salinity stress in wheat (Triticum aestivum L.) plants grown under ambient and elevated CO2 concentrations. Wheat plants inoculated or not inoculated with AM fungus were grown in two glasshouses with different CO2 concentrations (400 and 700 μmol l?1) and salinity levels (0, 9.5 and 19.0 dS m?1). Results showed that salinity stress decreased and elevated CO2 increased AM colonization. AM inoculation increased plant dry weight under elevated CO2 and salinity stress. Stomatal conductance, density, size and aperture of AM plants were greater than non‐AM plants. AM fungi enhanced NUE by altering plant C assimilation and N uptake. AM plants had higher soluble sugar concentration and [K+]: [Na+] ratio compared with non‐AM plants. It is concluded that AM symbiosis improves wheat plant growth at vegetative stages through increasing stomatal conductance, enhancing NUE, accumulating soluble sugar, and improving ion homeostasis in wheat plants grown at elevated CO2 and salinity stress.  相似文献   

4.
The effects of seeding rate (30, 60 and 90 seeds m?2), seeding date (14 January, 28 January and 12 February), seed weight (0.18 and 0.25 g seed?1), seeding depth (3 and 6 cm), and phosphorus fertilization rate (17.5, 35.0 and 52.5 kg P ha?1) and placement method (banded or broadcasted) on field pea (Pisum sativum L.) development and seed yields were investigated in irrigated field experiments conducted in northern Jordan in 2000 and 2001. Results and treatment responses were consistent in both years. Seeding rate, seeding date, seed weight and rate and method of phosphorus fertilization had significant effects on most traits measured; planting depth however did not affect any of the traits. Generally a positive correlation was observed between each factor and seed yield and yield components, with the exception of a negative correlation between seeding rate and yield components, and seeding date and yield and yield components. Increase in seeding rate from 30 to 90 seeds m?2, and increase in P fertilization from 17.5 to 52.5 kg ha?1 alone increased seed yields by 50 and 41 %, respectively. Each delay of 2 weeks for seeding from mid‐January resulted in reductions of 12 % in seed yields. Overall, the results revealed that a combination of early seeding (14 January), of large seeds at an high seeding rate (90 seeds m?2), with P fertilizer banding (52.5 kg P ha?1) maximize field pea yields in irrigated fields in semi‐arid Mediterranean environments. With such management pea seed yields can be as high as 2800 kg ha?1.  相似文献   

5.
Two field experiments were carried out in northern Greece during the 1993–94 and 1994–95 growing seasons to investigate the effect of nitrogen (N) supply on interspecific competition between wild mustard (Sinapis arvensis L.) and wheat (Triticum aestivum L.), barley (Hordeum vulgare =distichum L.) and triticale (Triticosecale). The presence of 140 S. arvensis plants m−2 until early March (averaged over N levels) did not have any adverse effect on the dry weight of all crops. However, its further presence significantly reduced the dry weight of wheat and triticale, but not that of barley. N fertilization (150 kg N ha−1 regardless of application time) slightly increased the dry weight of wheat and triticale grown without weed competition compared with that of control (0 kg N). On the contrary, the presence of wild mustard, until harvest, reduced dry weight of wheat and triticale by 31 and 26 %, respectively, while the corresponding reduction for barley was only 1.5 %. Furthermore, N fertilization (150 kg N ha−1) increased dry weight of wild mustard grown with wheat and triticale by 10 and 16 %, respectively, compared with that of control (0 kg N). Grain yield of wheat and triticale was reduced to 26 and 27 % by the competition of wild mustard, respectively, while the corresponding reduction for barley was only 3.5 %. Moreover, the wild mustard presence reduced total N content of wheat and triticale by 20 and 19 %, respectively, but this was not the case for barley.  相似文献   

6.
Growth and yield of wheat are affected by environmental conditions and can be regulated by sowing time and seeding rate. In this study, three sowing times [winter sowing (first week of September), freezing sowing (last week of October) and spring sowing (last week of April)] at seven seeding rates (325, 375, 425, 475, 525, 575 and 625 seeds m?2) were investigated during the 2002–03 and 2003–04 seasons, in Erzurum (Turkey) dryland conditions, using Kirik facultative wheat. A split‐plot design was used, with sowing times as main plots and seeding rates randomized as subplots. There was a significant year × sowing time interaction for grain yield and kernels per spike. Winter‐sown wheat produced a significantly higher leaf area index, leaf area duration, spikes per square metre, kernel weight and grain yield than freezing‐ and spring‐sown wheat. The optimum time of sowing was winter for the facultative cv. Kirik. Grain yields at freezing and spring sowing were low, which was largely the result of hastened crop development and high temperatures during and after anthesis. Increasing seeding rate up to 525 seeds m?2 increased the spikes per square metre at harvest, resulting in increased grain yield. Seeding rate, however, was not as important as sowing time in maximizing grain yield. Changes in spikes per square metre were the major contributors to the grain‐yield differences observed among sowing times and seeding rates. Yield increases from higher seeding rates were greater at freezing and spring sowing. We recommended that a seeding rate of 525 seeds m?2 be chosen for winter sowing, and 575 seeds m?2 for freezing and spring sowing.  相似文献   

7.
Growing barley (Hordeum vulgare L.) in the year of forage establishment is a common agronomic practice in marginal growing regions, but is often not recommended to growers. We examined the effect of silage barley production over an establishing timothy (Phleum pratense L.)‐clover (Trifolium pratense L.; Trifolium hybridum L.) forage sward in a 4‐year study near St. John's, Newfoundland, Canada. The experiment compared two barley varieties differing in plant height (semidwarf Chapais and Leger), three barley seeding rates and the effect of a forage understorey on forage (barley) production in the establishment year and forage (timothy‐clover) production in the subsequent year. The taller Leger yielded similar forage biomass to Chapais in the year of forage establishment, which (when planted at 375 plants m?2) was roughly twice that of a pure‐stand timothy‐clover mix. Increasing the barley seeding rate from 125 to 375 plants m?2 resulted in a linear increase in forage yield in the year of planting. The production of barley forage in the establishment year resulted in reduced timothy‐clover forage yield in the year following barley planted at 125 and 375 seeds m?2, but not for barley planted at 250 seeds m?2. Companion planting also altered forage species composition in that higher barley seeding rates resulted in 12–18 % less timothy and 2–4 % lower fibre levels in the year following planting. Barley seeded at rates of 250–375 seeds m?2 and undersown with a timothy‐clover mixture (harvested at mid‐milk) resulted in greater forage yield of poorer quality than pure‐stand timothy‐clover in the planting year, and a barley seeding rate of 250 seeds m?2 did not impede forage production in the subsequent year.  相似文献   

8.
The effects of four row spacings (17.5, 35.0, 52.5 and 70.0 cm) and five seeding rates (50, 100, 200, 400 and 800 viable seeds m?2) on seed yield and some yield components of forage turnip (Brassica rapa L.) were evaluated under rainfed conditions in Bursa, Turkey in the 1998–1999 and 1999–2000 growing seasons. Plant height, stem diameter, pods/terminal raceme, total pods/plant, seeds/pod and primary branches/plant were measured individually. The number of plants per unit area was counted and the lodging rate of the plots was scored. The seed yield and 1000‐seed weight were also determined. Row spacing and seeding rate significantly affected most yield components measured. The number of plants per unit area increased with increasing seeding rate and decreasing row spacing. Plant height was not greatly influenced by row spacing and seeding rate, but higher seeding rates reduced the number of primary branches and the stem diameter. The number of pods/main stem was affected by row spacing and but not by the seeding rate. Also, the number of seeds per pod was not affected by either the row spacing or the seeding rate. In contrast, the number of pods per plant clearly increased with increasing row spacing, but decreased with increasing seeding rate. The plots seeded at narrow row spacings and at high seeding rates were more sensitive to lodging. Seeding rate had no significant effect on seed yield in both years. Seed yield was similar at all seeding rates, averaging 1151 kg ha?1. However, row spacing was associated with seed yield. The highest seed yield (1409 kg ha?1) was obtained for the 35.0‐cm row spacing and 200 seeds m?2 seeding rate combination without serious lodging problems.  相似文献   

9.
The study aimed to address the optimal plant population density in maize that maximizes phenotypic expression and differentiation, and lessens environmental effects on genotypic expression in terms of the response to selection. A set of seven short-season hybrids (Rom set) was tested under rainfed conditions (2006, 2007) in Romania, and a set of seven long-season hybrids (Gr set) was tested with irrigation (2007) in Greece. Experimentation was conducted under ultra-low (ULD), low (LD), middle (MD), and high (HD) densities (0.74, 2.51, 4.20, 8.40 plants/m2 for the Rom set, and 0.74, 3.13, 6.25, 8.33 plants/m2 for the Gr set). Phenotypic expression and differentiation for grain yield were highest at the ULD. Coefficient of variation (CV) for grain yield, ear length and kernel row number decreased as density decreased. Environmental conditions and hybrid plant-yield potential (i.e., maximum yield per plant) were crucial for the optimal density that achieved the lowest environmental variance. For the Rom set the lowest CV for grain yield was obtained at the LD in the unfavourable season and at the ULD in the favourable season. The less acquired variance was achieved at the ULD for the highest yielding hybrids and at the LD for the lowest yielding hybrids, revealing a negative association between plant-yield potential and optimal density. Concluding, a density proximal to the ULD approximates absence of competition in maize, and optimizes three determinant parameters for successful selection: selection intensity, heritability and phenotypic differentiation.  相似文献   

10.
Integrating soil amendment biochar to legume‐based intercropping systems may amplify the intercropping benefits and lead to more sustainable production due to its positive effects on the soil physicochemical and biological environment. Fenugreek (Trigonella foenum‐graecum) is a legume used in an intercropping system in several countries in Southern Europe, the Middle East, and Asia. A barley cultivar and an Iranian fenugreek ecotype were studied in two replacement series experiments to find the best combination of the two species as well as the effect of adding biochar to the soil. Fenugreek and barley were grown in 4‐L pots in five density combinations (20:0, 15:5, 10:10, 5:15, 0:20) with and without application of biochar in sandy loam soil. The biomass, nitrogen (N) and carbon (C) amount of the two crops were measured fifty days after sowing, and the Relative Yield Total (RYT) was estimated. Our results showed that biochar application resulted in a higher total biomass, N and C amount in all combinations of fenugreek and barley. Total biomass was increased by biochar 19.2% when fenugreek was grown alone and 8.1 and 12.9% in series with 25 and 50% barley when biochar was added, respectively. Biochar increased dry matter, N and C accumulation in both crop species in the mixtures. An exception was the C amount of barley which was not influenced by biochar in intercropping. RYT values were largest for biomass, C and N amount in mixtures with 15 fenugreek plants per pot and 5 barley plants per pot corresponding to approximately 400 fenugreek plants per m mixed with 130 barley plants per m2. Biochar application increased RYT of the total dry weight by 2.7 and 5.5% in mixtures of 25 and 50% barley plants, RYT of the total nitrogen by 0.8% in mixtures with 25% barley plants, and RYT of the total carbon by 2.7 and 6.6% in mixtures with 25 and 50% barley plants. The RYT values declined with increasing number of barley plants as a result of a less competitive ability of fenugreek when growing in high barley densities. The yield was highest with intercropping but monoculture of barley also resulted in high yields. The total highest yield was found when approximately 130 fenugreek plants per m2 were mixed with 400 barley plants per m2. Mixtures with 75% fenugreek and 25% barley obtained RYT values larger than 1 for biomass, carbon and nitrogen percentages.  相似文献   

11.
This study was carried out in order to determine the effect of seed size on the growth and yield of durum wheat. Four field experiments, composed of six durum wheat (Triticum turgidum L. var. durum) varieties and three seeding sizes were conducted in north‐east Spain in 2000 and 2001 in randomized complete block designs. The growth of seedlings was dramatically affected by seed size. Large seeds produced greater plot stands, but the plants had fewer tillers, leaves and spikes and less green area and dry weight than plots from small seeds. Grain yield was 16 % greater in plots from large seeds, which resulted in greater biomass, green area index, spikes per m2 and heavier kernels than in plots from small seeds. Kernel weight was the yield component most related to grain yield in the three seed sizes. The percentage of yield variation explained by kernel weight increased as the weight of kernels increased. This was a consequence of the use of larger seeds, the same effect being observed when the comparison was made between varieties with different kernel weights. Selection for heavy kernel varieties may help to improve the yield of durum wheat in Mediterranean environments similar to that prevailing in north‐east Spain.  相似文献   

12.
Summary Maximizing the efficiency of selection for yield and baking quality of winter rye (Secale cereale L.) requires reliable knowledge on the pertinent population parameters. This study reports estimates of variances, heritabilities and genetic correlations from a) large (5 m2) drilled (LD) plots, b) micro drilled (MD) plots, and c) one-row plots of 4 spaced plants (SP). Thirty eight single crosses of rye were grown at two locations for two years in LD, MD and SP plots replicated 2, 4, and 6 times, respectively. Genotypic differences were significant in all plot types for all agronomic and quality traits, although estimates of genetic variances were smaller in LD than MD or SP plots for grain yield, 32-spike weight, and kernels per spike. Heritabilities on an entry mean basis (0.62 to 0.95) were similar among plot types, but on a single plot basis estimates were lower for SP than for MD or LD plots. Genetic correlations were high between all three plot types, with correlations between LD and SP plots being approximately 1.0 for falling number, thousand-kernel weight, and bloom date, 0.90 for grain yield, kernels per spike, test weight and height, and 0.70 for tiller number. Based on the high heritabilities achieved in small plots and the close agreement between MD- or SP- with LD-plot performance we conclude that greater use should be made of small plot types when selecting for yield and quality in winter rye.  相似文献   

13.
Field experiments conducted in 2007/08 and 2008/09 at the Changwu Agricultural Research Station on the Loess Plateau of China comprised three seeding rates (SR1: 225 seeds m−2, SR2: 280 seeds m−2, and SR3: 340 seeds m−2) and two root pruning treatments (W: root pruning in the over-wintering period and S: root pruning at the spring-growth stage), with the un-pruned wheat plants as controls. In the severe drought toward the end of the growing season of 2008, grain yield decreased as the seeding rate increased, but under the more favorable conditions in 2009 the reverse was true. Averaged over the seeding rates, grain yield was significantly increased in both W and S in both years; grain yield and yield components were higher in W; and S recorded the highest water use efficiency. The interaction between seeding rate and root pruning was not statistically significant. Leaf area index (LAI) and tiller density were higher as seeding rates increased whereas in W and S, increased LAI and decreased tillers significantly, but had no effect on fertile tillers. The rate of leaf photosynthesis was lower and root respiration was significantly higher at higher seeding rates, whereas in root pruning treatments, significantly higher leaf photosynthetic rate and lower root respiration were observed. Soil water contents were lower as seeding rate increased. A significant decrease in water use before stem elongation was observed in W, while S consumed less soil water than W and the control over the whole growing season. Post-heading accumulation of dry matter and its remobilization from vegetative parts to the grain was significantly greater at higher seeding rates. Post-heading accumulations of dry matter and grain yield were also significantly greater in W and S than the un-pruned plants, although pruning reduced both dry matter remobilization and its contribution to grain yield. The possibility of reducing the proliferation of roots to increase yields at higher seeding rates and conserving the soil water at different growing stages in water-limited environments is discussed.  相似文献   

14.
Competition and Productivity in Mixture of Oats and Wheat   总被引：1，自引：0，他引：1  
The research assesses the productivity of mixture of oats (Avena sativa) and wheat (Triticum aestivum), and compares two different approaches used in plant competition studies: replacement (substitutive) designs and additive designs. The experiment was carried out on sandy loam soil at the Experimental Station of Agricultural University of Wrocław (Poland). Oats and wheat were grown for grain as sole crops and in 1 : 1 replacement mixtures at three rates of seeding: 150, 300 and 600 viable seeds m−2. These designs allowed mixtures seeded at a rate of 300 and 600 seeds m−2 to be analysed according to either a replacement or an additive approach. In 1999, pure stand wheat and oats–wheat mixture yielded significantly more grain than oats grown alone but in 2000 there was no difference in yield. Wheat outcompeted oats in mixture but the relative competitive ability of the two species changed little with increasing seeding density. Relative yield total (RYT) for grain was significantly >1.0 (RYT = 1.07) in 1999 for the lowest seeding density, showing partial complementarity in use of limiting resources by the species in mixture. Based on grain yields, the results obtained from substitutive and additive mixtures were similar with respect to the relative yields and relative competitive ability of the two species concerned.  相似文献   

15.
The effects of deep placement (supplied at 20 cm depth from soil surface below plants) of 100 kg N ha?1 of N fertilizers, urea, coated urea or calcium cyanamide (lime nitrogen) on the growth, nitrogen fixation activity, nitrogen absorption rate and seed yield of soybean (Glycine max L. Merr.) plants were examined by comparing them with control plots without deep placement of N fertilizer in sandy dune field. In addition, three different inoculation methods of bradyrhizobia were used for each N treatment: (1) transplantation of 10‐day‐old seedling in a paper pot with vermiculite inoculated with Bradyrhizobium japonicum USDA110, (2) direct transplantation of inoculated 10‐day‐old seedlings, and (3) transplantation of 10‐day‐old seedlings in a non‐inoculated paper pot. The deep placement of N fertilizers, especially calcium cyanamide and coated urea, markedly increased the growth and total N accumulation in shoot, roots and nodules, which resulted in an increase in seed yield. Daily N2 fixation activity and N absorption rate were estimated by relative abundance of ureide‐N analysed from the concentration of N constituents (ureide‐N, amide‐N and nitrate‐N) in root bleeding xylem sap and increase in total N accumulation in whole plants at R1, R3, R5 and R7 stages. The total amount of N2 fixation was about 50 % higher in the plants with calcium cyanamide and coated urea deep placements compared with control plants. Deep placement of slow release fertilizers kept nodule dry weight higher in the maturing stage of seed, possibly through abundant supply of photoassimilate to the nodules by supporting leaf area and activity until late reproductive stages. The results indicate that deep placement of calcium cyanamide or coated urea enhances N2 fixation activity, which ultimately increases the seed yield. The promotive effect was observed with the seedlings transplanted in paper pot with inoculum of bradyrhizobia within any treatments, although nodulation by indigenous rhizobia was observed in the plants transplanted with non‐inoculated paper pot.  相似文献   

16.
Lentil (Lenus culinaris Medik) is a major grain legume crop in many developing countries in West Asia, North Africa and many other areas of the world. The effects of sowing date (1 January, 15 January and 2 February), plant density (80, 100 and 120 plants m?2), phosphorus level (0, 17.5, 35.0 and 52.5 kg P ha?1) and ethephon application [(1500 p.p.m. ethephon (2‐chloroethel phosphonic acid) applied 30 days after sowing] were investigated in the semiarid region in the north of Jordan. High yields were obtained for early sowing (1 January), high plant density (120 plants m?2), and high phosphorus application rate (52.5 kg P ha?1). Yield and yield components were not affected by ethephon application 30 days after sowing.  相似文献   

17.
Summary Twenty-seven progenies of interspecific crosses, involving ten Dianthus spieces (D. caryophyllus, D. chinensis, D. superbus, D. barbatus, D. japonicus, D. brachyzonus, D. versicolor, D. trifasciculatus, D. serotinus and D. knappii) and some complex interspecific hybrids (Diantini genotypes and D. Allwoodii selections) were grown from seed under 8 hr days at two light intensities: 12 W/m2 and 22 W/m2. Observations on individual plants were made on vegetative development and date of flowering. After six months, 178 plants were selected from 23 seedling progenies and the resulting clones were compared under 22 W/m2 and two photoperiods: 8 hrs and 24 hrs per day for a period of nearly six months. In the seedling stage, large differences were observed between progenies, e.g. in percentage generative plants (0–100%), plant length (3–78 cm) and plant fresh weight (0.5–68 g). Effects of light intensity were most pronounced in plant fresh weight (0.2–18 g in 12 W/m2 and 0.5–68 g in 22 W/m2). Progenies of D. chinensis were the earliest to flower. Most progenies of crosses between D. superbus and D. barbatus segregated into flowering and non-flowering (rosetting) plants. In the clonal stage, most clones originating from non-flowering seedlings remained vegetative (rosetting), while all clones from flowering seedlings were either in flower or in bud within six months. Average dates of flowering of seedling progenies and of their clones were highly correlated, suggesting that selection on flowering date at the seedling stage is effective. High correlations were also found between the average flowering date of seedling progenies and the number and total weight of flowers harvested per plant in their clones within six months from planting. Overall effects of LD in the clonal stage were much less spectacular than the effects of light intensity in the seedling stage.  相似文献   

18.
Increases in atmospheric carbon dioxide (CO2) concentration have stimulated interest in the response of agricultural crops to elevated levels of CO2. Several studies have addressed the response of C3 cereals to CO2, but the interactive effect of nutrient supply and CO2 on apical development and spikelet set and survival has not been investigated thoroughly. Hence, an experiment was conducted in the greenhouse to evaluate the effect of high (700 μmol CO2mol?1 air) and low (400 μmol mol?1) levels of atmospheric CO2 on apical development, spikelet set and abortion, and pre- and post-anthesis growth in spring barley (Hordeum vulgare L.) grown under high N (0.3 g N pot?1 before sowing ?1–0.11 g N pot?1 week?1) and low N (0.3 g N pot?1) regimes. The plants were grown in 5 L pots. Development of spike was hastened due to CO2 enrichment, and the C+ plants pollinated few days earlier than the C— plants. Carbon dioxide enrichment had no effect on date of ripening. Development of spike slowed following application of extra N, and plants pollinated 10 days later and matured 2 weeks later when compared with plants under low N. Carbon dioxide enrichment did not affect the number of spikelets at anthesis. Excess N decreased spikelet abortion and the increased maximum number of spikelets under both [CO2]. Barley plants did not tiller when grown in low [CO2] and low N. Increased endogenous IAA concentration in those plants, recorded three days before tillers appeared in other treatments, may have contributed to this. Carbon dioxide enrichment increased the C concentration of plants, but decreased the N concentration under high N regime. Both the C and N concentration of plants were increased under high N regime. Carbon dioxide enrichment increased the total dry matter of mature plants by 9 % under high N regime and by 21 % under low N regime. Under high [CO2] increased kernel number on tiller spikes, and increased kernel weight both on main stem and on tiller spikes resulted in a 23 % increase in kernel yield under low N regime and 76 % increase in kernel yield under high N regime. The rate of N application influenced growth and yield components to a greater extent than CO2 enrichment. At maturity, plant dry matter, kernel weight, the number of kernels per spike, and the number of spikes per plant were higher under high N regime than under low N regime. Long days (16 h), low light intensity (280 μmol m?2s?1), and at constant temperature of 20 °C high [CO2] increased kernel weight and the number of kernels on tiller spikes under high and low N application rate, but did not increase the number of kernels on main stem spike, or the number of tillers or tiller spikes per plant.  相似文献   

19.
We have performed chemical proximate analysis and determined the carbohydrate profile of mature seeds of Lupinus albus, cv. Rio Maior and Lupinus mutabilis, cv. Potosi plants, either well watered (ww) or subjected to a water-stress period (imposed from the 15th to 35th day after anthesis). Protein content from lupin seeds was 450 and 320 g kg−1 of seed on dry weight basis, for ww plants, respectively, of L. albus and L. mutabilis. Water stress did not affect protein content. The oil content of ww plants was about 120 g kg−1 of seed dry weight for L. albus and 180 g kg−1 of seed dry weight for L. mutabilis. Water stress reduced those values of half. The sugar content was about 90 g kg−1 for L. albus and 50 g kg−1 of seed dry weight for L. mutabilis, in ww plants. Water stress led to an increase in sugar content to 200 and 130 g kg−1 of seed dry weight, respectively, for L. albus and L. mutabilis. The α-galactosides amounted to 70 % of the total sugars (raffinose being 30 % and stachyose, 40 %) and sucrose was about 20 % of the total sugars. Water stress increased total carbohydrates and increased the sucrose/α-galactoside ratio, although reducing raffinose content and increasing sucrose content.  相似文献   

20.
Facing a steadily increasing world energy demand, jatropha, among other energy crops, has been reported to potentially contribute to biofuel production. A basic characterisation of plant responses to abiotic environmental factors is important for assessing the model‐assisted potential of this plant in view of the many agro‐ecological zones in which jatropha is presently cultivated. Two pot experiments and two field studies were used to record gas exchange parameters in response to light, nitrogen supply, atmospheric vapour pressure deficit (VPD), leaf age and time of measurements. Variation of N supply from 0 to 16 mm resulted in lower rates of photosynthesis (A) and stomatal conductance (gs) of treatment 0 mm N compared with other N levels, whereas the light compensation point (IC), quantum yield (QY) and dark respiration rates (Rd) were similar in all treatments. In the field, diurnal effects were evident with higher light‐saturated photosynthetic rate (Amax) and QY and lower IC and Rd in the morning than in the afternoon. Considering leaf age effects, fully expanded leaves had a lower Amax compared with expanding leaves and this variation in leaf gas exchange was not related to changes in the chlorophyll index value (SPAD) which steadily increased with leaf age. QY of field and greenhouse plants varied from 0.023 to 0.037 and was substantially lower than in C3 plants. A was positively correlated with gs in a hyperbolic function. A varied from 0.64 to 21.13 μmol m?2 s?1 and gs varied from 12 to 469 mmol m?2 s?1. With increasing VPD, gs decreased, but this response differed between the field experiments and the two pot experiments which contrasted each other distinctively. Applying the inverse logistic function of Webb (Ecological Modeling, 56 (1991), 81), the maximal stomatal conductance of jatropha was in the range of 382 mmol m?2 s?1 and gs is predicted to be close to zero at 5 kPa. These data altogether indicate that light absorption characteristics of single leaves and carbohydrate status parameters should be investigated further to explain the low QY and the pronounced diurnal variation.  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