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1.
Phosphorus (P) is essential macronutrient for soybean [Glycine max (L.) Merr.] growth and function. The objective of this study was to determine effect of phosphorus nutrition (including phosphorus nutrition level and interruption of phosphorus supply) on nitrogen accumulation, nodule nitrogen fixation and yield of soybean plants by 15N labeling with sand culture. The results showed that they all presented a single peak curve with improvement of phosphorus nutrition level, when phosphorus concentration of nutrient solution was about 31 mg/L, they all reached the maximum and effect of phosphorus nutrition level on nodule nitrogen fixation was lower than that on yield formation level. Interruption of phosphorus supply during soybean growth period, nitrogen accumulation and nodule nitrogen fixation were seriously inhibited, and yield was decreased significantly when interruption of phosphorus supply during V3-R1 and R1-R5 period, while interruption of phosphorus supply during R5-R7 period had no significant effect on nitrogen accumulation, nodule nitrogen fixation and yield. So soybean nitrogen metabolism and yield were sensitive to phosphorus nutrition in the V3-R5 period, those were not sensitive to phosphorus nutrition after R5 period.  相似文献   

2.
玉米/大豆带状套作可以充分利用光环境,提高单位土地面积物质产出。为探明玉米/大豆带状复合种植模式下不同空间配置对大豆冠层光环境、形态、产量及系统效益的影响,进而为大豆高产优质栽培提供依据,本研究选用半紧凑型（‘川单418’）和紧凑型（‘荣玉1210’）玉米品种与大豆带状套作,固定带宽为200 cm,玉米采用宽窄行种植,玉米窄行距设置3个处理：20 cm、40 cm、60 cm;并以单作大豆（SS）作为对照。分析透光率、形态、光合色素、荧光参数、生物量和系统产量的变化规律。结果表明：套作大豆冠层透光率、红光/远红光（R/FR）比值随玉米窄行距的增大而逐渐降低;套作下大豆茎粗、节数、茎干重和全叶干重均随玉米窄行距增大呈降低趋势,最大值出现在玉米窄行距20 cm处理下;与单作大豆相比,两个玉米品种下大豆茎粗、节数、茎干重和全叶干重均显著降低,而第2节间长和主茎长显著升高。套作下大豆叶片光合色素含量随玉米窄行距的增大而逐渐降低,各行距处理及不同玉米品种下套作的叶片光合色素含量均低于单作大豆。大豆叶片荧光参数Fv/Fm、NPQ、Fq''Fm''和Fq''/Fv''随玉米窄行距的增大均呈先增大后减小的趋势,而Fo变化趋势与之相反。玉米收获后,大豆光环境得到改善并迅速恢复生长,套作大豆形态生理指标与单作差异减小,但由于前期玉米的遮荫,各套作处理间大豆产量差异仍显著。通过系统效益分析,在玉米窄行距40 cm处理下,套作系统综合产量最高,两玉米品种下玉米、大豆产量平均分别为8 559.52 kg·hm-2、1 717.60 kg·hm-2,土地当量比平均达1.57。本试验中大豆与两个株型玉米套作,大豆形态生理指标差异影响不显著。因此,选择紧凑或半紧凑玉米品种,适度缩小玉米窄行距可以显著改善带状套作大豆的生长环境,提高其生物量和产量。  相似文献   

3.
Annual plants may partition carbon (C) preferentially to reproductive structures slowing root elongation and subsequent nutrient uptake. Although foliar applications of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) supplement uptake by roots, soybean [Glycine max (L.) Merr.] yield increases have not been found in most studies. Experiments were designed to determine if foliar applications of boron (B), magnesium (Mg), or B+Mg would increase soybean yield and if soybean would respond to B applied to the soil several weeks prior to planting. Foliar B or Mg applied separately four times during reproductive growth did not affect soybean yield. However, four foliar applications of B+Mg increased soybean yield 12% at Mt. Vernon and 4% at Columbia over a three‐year period. Two foliar applications of B+Mg during the late reproductive stages increased soybean yield 8% over a two‐year period. The yield increase from foliar B+Mg treatment resulted from an increased number of pods on the main stem (18%) and branches (44%). A 2.8 kg/ha B application to soil eight weeks prior to planting increased soybean yield 11% during the first year and 13% the second year but had no effect on soybean yield by the third year after application. When results from the first two years were combined, 2.8 kg/ha B applied to soil increased the number of pods per branch by 17% and the number of branch pods per plant by 39%. Foliar applications of B+Mg increased soybean yield in four of six site‐years in the three‐year experiments at two locations.  相似文献   

4.
Analysis of uppermost fully expanded leaves is useful to detect a deficiency of mineral nutrients such as phosphorus (P) and potassium (K) in soybean. Although, the leaf P or K status aids in fertilizer management, information on nutrient seasonal relationships with growth and yield traits at maturity are limited. To investigate this, soybean was grown under varying P or K nutrition under ambient and elevated CO2 concentrations. Results show significant relationships of the relative total biomass and yield‐related traits with the foliar P and K concentrations measured several times in the season across CO2 levels. However, the relationships established earlier in the season showed that the growth period between 25 and 37 d after planting (DAP), representing the beginning of flowering and pod, respectively, is the best for leaf sampling to determine the foliar P or K status. The leaf P and K status as well as the critical leaf P (CLPC) and K (CLKC) concentrations for traits such as seed yield peaked around 30 DAP (R2 stage) and tended to decline thereafter with the plant age. The CLPC and CLKC of seed yield indicate that the leaf P and K concentration of at least 2.74 mg g?1 and 19.06 mg g?1, respectively, in the uppermost fully expanded leaves are needed between 25 and 37 DAP for near‐optimum soybean yield. Moreover, the greatest impact of P and K deficiency occurred for the traits that contribute the most to the soybean yield (e.g., relative total biomass, seed yield, pod and seed numbers), while traits such as seed number per pod, seed size, and shelling percentages were the least affected and showed smaller leaf critical concentration. The CLPC or CLKC for biomass and seed yield was greater under elevated CO2 24–25 DAP but varied thereafter. These results are useful to researchers and farmers to understand the dynamics of the relationship of pre‐harvest leaf P and K status with soybean productivity at maturity, and in the determination of suitable growth stage to collect leaf samples.  相似文献   

5.
Abstract

The main objective of this study was to increase the productivity of soybean [Glycine max (L.) Merr. cv. Enrei] seed by deep placement of controlled release nitrogen fertilizers and by the application of different methods of inoculation of bradyrhizobia. Ten days old seedlings in an inoculated paper pot (IPP), in a non-inoculated paper pot (NIPP), and those grown in a vermiculite bed without paper pot (DT) were transplanted to an upland field converted from a drained paddy field in Nagaoka. In addition to the basal application of 16 kg N ha?1 in the surface layer (Control), deep placement of 100 kg N ha?1 of urea (Urea), 100-day type coated urea (CU-100), and calcium cyanamide (CaCN2) treatments were applied at the depth of 20 cm. In the IPP method, a significantly higher seed yield was obtained with the deep placement of CaCN2 and CU-100 compared with the Urea and Control treatments. A similar tendency was observed for the DT and NIPP methods. Among the same N fertilizer treatments, the seed yield for IPP and DT tended to exceed that for NIPP, although the NIPP roots also showed nodulation probably due to infection with indigenous bradyrhizobia. The percentage of nitrogen derived from atmospheric N2 estimated by the simple relative ureide method was higher in the plants with CU-100 and CaCN2 compared with those with the Urea and Control treatments at the RI stage, suggesting that the basal deep placement of CaCN2 or CU-100 for soybean cultivation enabled the supply of N without concomitant depression of N2 fixation. Thus the deep placement of cheaper CaCN2 was found to be as effective as that of CU-100 for enhancing the soybean seed yield.  相似文献   

6.
为探寻玉米-大豆套作体系下作物间的资源竞争关系,揭示玉米-大豆套作系统的增产机理,本研究以玉米-大豆套作系统(简称玉豆套作)为对象,通过2 a大田定位试验,研究了玉豆套作带状连作(A1)、玉豆套作带状轮作(A2)、玉豆套作等行距种植(A3)、玉米单作(A4)、大豆单作(A5)5种种植方式对玉米、大豆的产量、养分吸收及种间竞争能力的影响。结果表明,与单作和等行距种植相比,带状种植的玉米产量降低、大豆产量显著增加,A2的大豆产量分别比A5和A3高25.5%和89.2%。与带状连作相比,带状轮作促进玉米增产和对N、P、K的吸收,玉米籽粒产量及植株N、P、K的吸收总量分别提高7.5%、18.5%、9.1%、14.1%。与大豆单作相比,带状套作显著增加了大豆的经济系数和养分收获指数,A2的经济系数和植株N、P、K收获指数分别增加40.9%、11.9%、20.6%、39.9%。带状种植方式下,玉米对N、P、K的竞争力弱于大豆(Ams0,CRms1),但带状轮作提高了玉米的种间竞争力和营养竞争比率。玉米-大豆套作体系下,相对带状连作和等行距种植,带状轮作种植有利于玉米与大豆间的和谐共生,促进了玉米、大豆对养分的吸收,提高了系统的产量和土地当量比率(LER)。  相似文献   

7.
Foliar application of fertilizers can guarantee the availability of nutrients to rice for obtaining higher yield. Rice responds favorably to macro- and micronutrients and the tolerance to salinity hazards improves by decreasing the N/S ratio. In this study, results showed that nutrient concentrations (g L?1) for rice are: nitrogen (N) 108.0, phosphorous (P2O5) 6, potassium (K2O) 81.0, calcium (CaO) 15.0, and magnesium (MgO) 6 g L?1; and for iron (Fe), manganese (Mn), zinc (Zn), cupper (Cu), boron (B), molybdenum (Mo) and silicon (Si) the recommended concentrations are 0.6, 0.45, 0.21, 0.06, 0.09, 0.0002 and 0.004 g L?1, respectively. A significant increase was recorded in number of panicles m?2, 1000 grain weight, biological yield and grain yield with foliar application of nutrients. Five foliar applications of nutrients resulted in maximum number of panicles m?2, grains panicle?1, 1000 grain weight and biological yield. It is concluded that five foliar applications of balanced amounts of fertilizers at the seedling stage (two sprays), tillering (single spray) and at panicle initiation and panicle differentiation (two sprays) helped in enhancing yield and yield components of rice. In this research, five foliar applications produced the smallest damaging effects of blast (Pyricularia oryzae) in rice.  相似文献   

8.
种植密度和氮磷钾肥对药用菊花的产量及光合效率的影响   总被引：2，自引：0，他引：2  
周可金  章力干  张俊霞  马成泽 《土壤》2010,42(4):579-583
采用4因素5水平通用旋转组合设计,研究了种植密度和N、P、K肥4种栽培因子对药用亳菊的产量、单株开花数以及群体光合速率的主效应和互作效应。结果表明:N、K、P肥和种植密度对产量、净光合速率的影响均达到显著和极显著水平;N肥对单株开花数和单朵花重量达极显著正效应,K肥也有一定效应,其他因素效应微弱。影响亳菊产量的最主要因素是N肥,其次是密度。4种栽培因子对产量的影响顺序为:N密度KP;对净光合速率的影响顺序为:NK密度P。获得亳菊高产的适宜密度为:5.5～6.0万株/hm2,施肥剂量范围为:N339.5～384.7kg/hm2,P2O5161.2～195.7kg/hm2,K2O291.5～344.0kg/hm2,三者的合理配比为:N∶P2O5∶K2O=1∶0.51∶0.89。  相似文献   

9.
Abstract

A greenhouse experiment was conducted on clay loam soil of pH 7.8 to evaluate the effect of P, N fertilization and foliar applied Mn on yield and nutrient concentration in leaves and seeds of soybean. A significant yield increase was obtained for each added increment of P fertilizer up to 30 kg P2O5/acre. At application rates of 0, 15, 30 & 45 kg P2O5/acre, the seed yield was subsequently 27.8, 65.8, 82.8 & 83.6% of the maximum yield obtained at the maximum calculated P level. The yield increase accounted 14.2 and 10.2% for N and Mn applications. In all treatments, in which P was combined with N, the seed yield was relatively higher than with P or N applied alone.

Phosphorus, N and Mn content in leaves and seeds were positively correlated with the applied nutrient fertilizers. At any given level of applied P and Mn, P content was significantly higher in +N than ‐N treatments. By Mn application, P content in leaves and seeds was decreased. Phosphorus and Mn applications did not influence N content in leaves and seeds.  相似文献   

10.
Soybean (Glycine max L.), being a leguminous oilseed crop, requires relatively higher amount of sulfur (S) and boron (B) for optimum yield and quality. A field experiment was conducted to evaluate the effect of S and B application on growth, yield, and quality of soybean, and to find out their optimum doses for the best crop performance in acidic soils of northeast India. The treatments comprised four levels of S (0, 20, 40, and 60 kg/ha) and four levels of B (0, 0.5, 1.0, and 1.5 kg/ha) in factorial combination. In general, application of S and B, either alone or in combination, significantly increased the growth, yield, and quality of soybean. When applied alone, S resulted in best yield (1767 kg/ha) at S40, which was 21.2% higher than the yield at control (1458 kg/ha), while B produced maximum yield (1578 kg/ha) at B1.5 (8.23% higher than control). Interestingly, 57.4% yield improvement over control was recorded with combined application of S40 and B1.5, which shows their synergistic effect on crop performance. Similarly, with concurrent application of S40 and B1.5, a 28% increase in protein and 33% increase in oil content of soybean were recorded relative to control. In general, S40 + B1.5 also resulted in the highest nutrient nitrogen, phosphorus, potassium sulfur, and boron (NPKSB) uptake by soybean. Based on these results, we recommend the conjunctive use of 40 kg S and 1.5 kg B/ha for the best yield and quality of soybean on acidic soils of northeast India and other regions with similar soils.  相似文献   

11.
不同磷肥水平对大豆磷营养状况和产量品质性状的影响   总被引：16，自引：1，他引：16  
本试验选用近年来黑龙江省推广面积较大并具有代表性的3个基因型大豆品种作为试验材料,采用盆栽试验,利用钼锑抗比色法测定了大豆生育期各器官磷素含量,并测定了单株产量及成熟子粒蛋白质和脂肪含量,结果表明:施磷量对不同大豆品种植株及各器官磷素含量有较大影响;不同品种不同处理全株及各器官磷素含量从分枝期逐渐增加,开花期达到高峰,随后下降至成熟期;同一品种不同处理间高蛋白品种和中间型品种是P150处理全株磷积累量最高,高油品种是P225处理全株磷素积累最高;生育期内只有适宜施磷才能促进磷素含量达到最高峰;同一处理不同品种间是高油品种磷素积累量大于中间型品种和高蛋白品种,说明高油品种需磷量多于中间型品种和高蛋白品种。高蛋白品种和中间型品种P150处理单株产量和子粒蛋白质含量最高,高油品种P75处理单株产量和子粒蛋白质含量最高。3个品种脂肪含量均以P225处理最高。  相似文献   

12.
Abstract

Greenhouse‐pot experiments were conducted to compare wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merrill] in terms of their potassium (K) and magnesium (Mg) uptake. Previously, a field study indicated that various rates of K and Mg fertilization did not produce a significant wheat‐yield response. However, a yield increase with residual K and Mg was measured for the subsequent soybean crop. The 0 to 15 cm layer of Norfolk loamy fine sand (fine loamy, siliceous, thermic Typic Kandiudult) from two different sites was used for the pot experiments. Soil from both sites had a pH of 5.1. Potassium as potassium sulfate (K2SO4) was mixed into the soil from the K‐deficient site and Mg as magnesium sulfate (MgSO4) was mixed into the soil from the Mg‐deficient site. ‘Florida 301’ wheat and ‘Cobb’ soybean were grown in winter and summer, respectively.

Soybean and wheat were similar in K uptake/g of roots on the first and second sampling dates. However, by the third sampling date, K uptake/g of wheat roots was about twice as high as for soybean. Potassium uptake/cm of soybean roots was two to five times that of wheat at each sampling date. Magnesium uptake/g of soybean roots was about four to five times as high as wheat on each sampling date. Similarly, Mg uptake/cm of soybean roots was 10 to 30 times higher than for wheat. Soybean showed higher total K and Mg content than wheat, suggesting that soybean has a higher demand for both K and Mg. The higher demand for K and Mg by soybeans than by wheat suggests that wheat could meet its demand for K and Mg at much lower soil levels than that for soybean. This would also explain a grain‐yield response to K and Mg by soybeans in the previously reported field study, despite a lack of yield response by wheat grown on the same site.  相似文献   

13.
A field and greenhouse experiments were conducted to determine the requirement of Fe nutrient supplied through foliar and soil application in soybean inoculated with different selected isolates of exotic and native Bradyrhizobium spp. in saline soils. Six soybean genotypes and three Bradyrhizobium spp. were used for the greenhouse experiments, whereas only two soybean genotypes, namely TGx-1336424 and GIZA, were selected for further study under field conditions. Two levels of FeSO4 (0 and 4 mg Fe kg?1 soil) directly supplied to the soil and three levels of Fe-ethylenediaminetetraacetic acid (0–2% of Fe) through foliar application were used for greenhouse and field experiments, respectively. The results of the greenhouse experiment indicated a non-significant effect of Fe application on nodulation and shoot biomass in soybean. Fe application did not improve the grain yield and total biomass yield in soybean inoculated with UK isolate and local isolate but showed remarkable improvement with TAL-379. High soil native N might be the cause for insignificant effect of Fe applied at 2% in highly effective inoculated plants. Therefore, it can be concluded that the symbiotic effectiveness of Bradyrhizobium sp. and the native soil N would affect the soybean Fe requirement supplied through foliar application.  相似文献   

14.
In order to reduce blossom‐end rot occurrence in greenhouse‐grown peppers, experiments were conducted to determine whether foliar applications of antitranspirants would decrease transpiration of pepper (Capsicum annuum L. cv. Hungarian Wax or Midal) leaves and subsequently redirect the flow of calcium (Ca) from plant foliage to developing fruit. Foliar calcium nitrate [Ca(NO3)2] applications were also carried out as a possible means to increase fruit Ca concentration and reduce blossom‐end rot. Initial studies indicated that two antitranspirant applications of 2.5% ‘Vapor Gard’ (di‐1‐p‐menthene) early in the fruiting phase of ‘Hungarian Wax’ peppers significantly increased early yield and tended to increase total Ca in the fruit. In subsequent experiments, weekly applications of either antitranspirant ‐ 1% ‘Vapor Gard’ or 1% ‘Folicote’ (a wax emulsion concentrate) ‐ throughout the fruiting phase significantly increased fruit Ca of ‘Midal’ peppers during at least part of the reproductive stage, and significantly reduced blossom‐end rot‐affected yield. Weekly Ca(NO3)2 applications significantly elevated leaf Ca as well as fruit Ca concentrations, and was the most effective treatment in alleviating blossom‐end rot. However, all weekly Ca(NO3)2 and antitranspirant treatments caused significant declines in marketable yield, so that these treatments, although effective in reducing blossom‐end rot, cannot be recommended for commercial use.  相似文献   

15.
Investigations into the effect of soybean cyst nematode (SCN, Heterodera glycines, Ichinoe) on the yield components of soybean [Glycine max (L.) Merr.] have shown that pod numbers are reduced with increasing SCN initial populations (Pi) present in the soil at planting. The main method by which SCN alters pod numbers is through reductions in the number of branches per plant. Foliar applications of boron (B) and B in combination with magnesium (Mg) (B+Mg) increase yield of soybean not infected with SCN by increasing pod number per plant, especially the number of pods on branches. The objective of this research was to determine if foliar applications of B and B+Mg ameliorates the effect of SCN by increasing yield on branches. Field experiments were conducted in 1993 and 1994 in 1 m2 microplots to compare foliar applied B and B+Mg to a control treatment. Foliar applications were made at four intervals spaced throughout soybean reproductive development of Pioneer brand 9391, an SCN susceptible cultivar. There were 12 levels of SCN Pi in 1993 and 11 levels in 1994. For each treatment, including control, grain yield was regressed on SCN Pi. Yield was reduced with increasing SCN Pi in both years, but the rate of decrease did not differ among treatments. In addition, ANOVA of yield components revealed no treatment effects on the number of branches per plant, the number of branch pods per plant, or the total number of pods per plant. Thus, foliar applications of B or B+Mg did not ameliorate the effects of SCN on soybean.  相似文献   

16.
The application of manure compost is an effective way to increase soybean [Glycine max (L.) Merr.] yield and nitrogen (N) fertility in drained paddy fields. We investigated changes in soil N mineralization during soybean cultivation using reaction kinetics analysis to determine the contribution of increased N mineralization after manure compost application (at a rate of 0 to 6?kg?m?2) on N accumulation and seed yield of soybean under drained paddy field conditions. The seed yield and N accumulation decreased markedly in the second and third year of the experiment, but soil N mineralization increased in both years. No decrease in soil N mineralization occurred even after two soybean crops. Soil N availability was not the main cause of decreased soybean yield in the second and third years. The differences in plant aboveground N content between plots with and without manure compost was similar to the increase in N mineralization caused by manure compost application in the second and third years. The application of 6?kg?m?2 of manure compost increased the amount of ureide-N and nitrate-N in soybean in the third year. Our results suggest that manure compost application increases soil N mineralization and soybean N2 fixation, resulting in increased N accumulation and seed yield. However, the soybean yield remained less than 300?g?m?2 in the second and third years (i.e., below the yield in the first year) at all levels of manure compost application due to the remarkable decrease of N accumulation in the second and the third crops.  相似文献   

17.
Maize(Zea mays L.), a staple crop in the North China Plain, contributing substantially to agricultural nitrous oxide(N_2O)emissions in this region. Many studies have focused on various agricultural management measures to reduce N_2O emissions. However, few have investigated soil N_2O emissions in intercropping systems. In the current study, we investigate whether maize-soybean intercropping treatments could reduce N_2O emission rates. Two differently configured maize-soybean intercropping treatments, 2:2 intercropping(two rows of maize and two rows of soybean, 2M2S) and 2:1 intercropping(two rows of maize and one row of soybean,2M1S), and monocultured maize(M) and soybean(S) treatments were performed using a static chamber method. The results showed no distinct yield advantage for the intercropping systems. The total N_2O production from the various treatments was 0.15 ± 0.04–113.85 ± 12.75 μg m~(-2) min~(-1). The cumulative N_2O emission from the M treatment was 16.9 ± 2.3 kg ha~(-1) over the entire growing season(three and a half months), which was significantly higher(P 0.05) than that of the 2M2S and 2M1S treatments by 36.6% and 32.2%, respectively. Two applications of nitrogen(N) fertilizer(as urea) at 240 kg N ha~(-1) each induced considerable soil N_2O fluxes. Short-term N_2O emissions(within one week after each of the two N applications) accounted for 74.4%–83.3% of the total emissions. Soil moisture, temperature, and inorganic N were significantly correlated with soil N_2O emissions(R~2= 0.246–0.365, n =192, P 0.001). Soil nitrate(NO_3~-) and moisture decreased in the intercropping treatments during the growing season. These results indicate that maize-soybean intercropping can reduce soil N_2O emissions relative to monocultured maize.  相似文献   

18.
Abstract

An experiment was conducted on some soils of Mesa de Guanipa, which are sandy, acid (pH 5.5), and have low levels of available P, K, Ca, and Mg. These soils are located at the Agropecuaria Guanipa farm in El Tigre, Anzoategui State, Venezuela. The main objective was to evaluate rates and sources of P, and rates of K on soybean yield (variety FP‐3), which is an activity of the project “Maximum soybean yields in Venezuela”;, financed by the Potash and Phosphate Institute of Canada. The rates and sources of P were 0, 75, and 150 kg P2O5/ha as triple superphosphate (TSP) and diammonium phosphate (DAP). Rates of potassium as K2O were 0, 60, and 120 kg/ha as potassium chloride (KCl). The experimental design was a randomized complete block with 3 replications and a final plant density equivalent to 400,000 plants/ha. A basic application of nitrogen and magnesium fertilizers was made to guarantee the supply of those nutrients. The soybean seeds were inoculated at planting with NITROBAC to ensure nodule formation. Yield results showed a good response to P application and low response to K. The combination of 150 kg P2O5/ha as TSP and 60 kg K2O/ha as KCl produced the maximum soybean grain yields of 2.857 kg/ha at 12% moisture as well as the highest net return of U.S.$393.9/ha. From the results obtained in this experiment as well as ones to be established during the next 3 years, it is expected that there will be an adjustment in the fertilization program followed by the soybean farmers of Mesa de Guanipa as they are now applying higher rates of K and lower rates of P than that applied in this experiment.  相似文献   

19.
Soybean (Glycine max (L.) Merrill) plants normally abort a high percentage of flowers and pods. This study was conducted to determine the effect of P nutrition on flower and pod abscission in soybean. Williams 82 soybeans were established in hydroponic culture in the greenhouse at four levels of P (0.45 mM, 0.20 mM, 0.10 mM or 0.05 mM), and main stem flowers and pods were counted every two days from flowering to maturity. The two highest P treatments had similar flower production, pod production, pod abortion, seed weight and seeds per pod, but the 0.20 mM P treatment had 20% lower dry matter production and 19% lower seed yield. At P supplies of 0.10 or 0.05 mM, flower production, pod production, flowers per node, pods per node, seed yield, seed number and weight per seed were less (P < 0.05) than at 0.20 mM. Flowers produced per main stem node and seeds per pod were largely unaffected by limited P. Plants supplied 0.10 or 0.05 mM P aborted more flowers and pods than did those supplied 0.45 or 0.20 mM P. At P supply of 0.05 mM, flower, pod and total abortion was 80%, 49% and 90%, respectively. Flower and pod production were 50% and 78% less, while plant dry weight, seed yield and weight per seed were 83%, 90% and 23% less, respectively for the 0.05 mM P treatment compared to control. The data indicate that the primary effect of limited P on reproductive growth of soybean is to increase flower and pod abortion.  相似文献   

20.
The present study aimed to investigate the effect of selenium on flowering indices, sex determination of flowers, and yield of cucumber plant under heavy metal stress conditions. Treatments consisted of selenium (0, 4, 6, 8 mgL?1) and heavy metals of cadmium (0, 20, 25 µM) and lead (0, 60, 100 µM), which were applied in three stages during the experiment period. The results of this study showed that the stress of heavy metals with a negative effect on flowering indices resulted in delayed flowering and changing flower’s sex toward male flowers. Furthermore, delayed fruiting and significant decreases in fruit growth indices and total yield was observed in plants treated with cadmium and lead. Adding selenium to the culture medium resulted in accelerated flowering (reducing the time and number of nodes needed until the first flower emerges), the emergence of more male flowers, increased the ratio of the number of female flowers to male flowers in plants under stress, and the highest effect of this element was observed at the concentration 6?mg/L. Based on this results, the application of 4and 6mg/L selenium in stress and non-stress conditions enhanced fruiting (a significant reduction in the time required from cultivation to fertilize the first flower and the formation of fruit in lower nodes) and significantly increased the number of fruits, fruit length and diameter, single fruit weight and total yield, and the greatest effect of this element was observed in 6?mg/L concentration. The results of this study showed that selenium has a positive effect on control of stress conditions and improvement of flowering indices and total yield in cucumber plant under the stress of heavy elements of lead and cadmium.  相似文献   

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