Chemical Composition and Mineral Content of Common Vetch Seeds during Maturation

ABSTRACT

Common vetch (Vicia sativa L.) is an important legume cultivated for feed grain and forage in the Mediterranean and Central Asia regions. Little information is available about the changes in seed mass, chemical composition, and mineral concentration in the developing seeds of common vetch. Therefore, the objective of this experiment was to study the changes in seed mass, moisture content, fat, fiber, proteins, carbohydrates, reducing sugars, and macro- and microelements in common vetch seeds sampled at four pod developmental stages described based on pod color. Common vetch pods were harvested at four pod developmental stages: 1) full-size seed (FS), 2) greenish-yellow pods (GY), 3) yellow pods (Y), and 4) brown pods (B). Common vetch seeds attained maximum mass accumulation when pod color turned to yellow (the Y stage), which was a good indication of seed physiological maturity in common vetch. Results showed that ash, fat, fiber, protein, and carbohydrate content increased between the FS and GY stage. There was no significant change in the accumulation of these components at the Y stage as compared with the GY stage. During the desiccation phase (the Y to B stage), there was an increase in carbohydrate and reducing sugars and a decrease in proteins. Seed content (μg seed^?1) of macro- and microelements levels increased as the seed matured, reaching the maximum level by the GY stage [for phosphorus (P), sodium (Na), zinc (Zn), and manganese (Mn)], the Y stage [for copper (Cu)], and the B stage [for potassium (K) and iron (Fe)]. These results suggest that the majority of seed chemical composition was accumulated by the GY stage where farmers can harvest common vetch seed without reducing seed mass and nutrient loss. These data serve as a useful characterization of changes in chemical composition based on pod developmental stages for further studies.     

Grain legumes differ in nitrogen accumulation and remobilisation during seed filling

In grain legumes, the N requirements of growing seeds are generally greater than biological nitrogen fixation (BNF) and soil N uptake during seed filling, so that the N previously accumulated in the vegetative tissues needs to be redistributed in order to provide N to the seeds. Chickpea, field bean, pea, and white lupin were harvested at flowering and maturity to compare the relative contribution of BNF, soil N uptake, and N remobilisation to seed N. From flowering to maturity, shoot dry weight increased in all crops by approximately 50%, root did not appreciably change, and nodule decreased by 18%. The amount of plant N increased in all crops, however in field bean (17?g?m^?2) it was about twice that in chickpea, pea, and lupin. The increase was entirely due to seeds, whose N content at maturity was 26?g?m^?2 in field bean and 16?g?m^?2 in chickpea, pea, and lupin. The seed N content at maturity was higher than total N accumulation during grain filling in all crops, and endogenous N previously accumulated in vegetative parts was remobilised to fulfil the N demand of filling seeds. Nitrogen remobilisation ranged from 7?g?m^?2 in chickpea to 9?g?m^?2 in field bean, and was crucial in providing N to the seeds of chickpea, pea, and lupin (half of seed N content) but it was less important in field bean (one-third). All the vegetative organs of the plants underwent N remobilisation: shoots contributed to the N supply of seeds from 58% to 85%, roots from 11% to 37%, and nodules less than 8%. Improving grain legume yield requires either reduced N remobilisation or enhanced N supply, thus, a useful strategy is to select cultivars with high post-anthesis N₂ fixation or add mineral N at flowering.     

Effect of Harvest Timing on Yield and Mineral Nutritional Value of Kabuli Type Chickpea Seeds

Chickpea (Cicer arietinum L.) seeds are a good source of protein and mineral nutrients. However, there is no information regarding harvest timing on yield and mineral composition of chickpea seeds. The effect of harvest timing on seed yield, some yield components and mineral nutritional value of seeds of field grown chickpea plants in two different sites were studied. The mineral composition of chickpea straw depending on harvest timing was also evaluated in order to explain the variations of seed mineral concentrations in sink-source relationship manner. Yield and mineral nutritional value of chickpea were significantly affected by harvest timing. When compared to the seed yield at optimal harvest time, seed yield was 18% and 9% lower in the early harvest and 27% and 31% in the late harvest in Site 1 and Site 2, respectively. Late harvest of chickpea crops resulted in significant pod dropping and shattering. Generally, protein, phosphorus (P), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and manganese (Mn) concentrations of the seeds in optimal harvest were found to be greater than in early and late harvested plants. Harvest timing also results in significant variations in straw mineral nutrient concentrations of the plants. As the results of this study, it was concluded that the harvest timing is critical for yield losses and mineral nutritional value of chickpea seeds.     

Impact of Boron Deficiency on Changes in Biochemical Attributes,Yield, and Seed Reserves in Chickpea

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.     

播期与施氮量对花生干物质、产量及氮素吸收利用的影响

[目的]在大田条件下,研究播期与施氮量对不同类型花生产量、干物质积累、氮素吸收及利用的影响,为花生高产和养分资源高效利用提供技术支撑.[方法]选择普通型大花生品种'花育22号'和高油酸花生品种'冀花16号'为材料,设3个施氮水平:0、120、240?kg/hm2?(分别表示为N0、N120、N240);4个播期:4月3...     

Dry Weight and Nitrogen Content of Chickpea and Winter Wheat Grown in Pots for Three Rotations

ABSTRACT

Chickpea [Cicer arietinum (L.)] cultivars ‘ICCV-2’ and ‘Sarah’ were studied along with a control, multistrain, TAL 1148, and TAL 480 Bradyrhizobium strains to determine the effect(s) of cultivar and inoculum on dry weight (DW) and nitrogen (N) content of the legume, as well as soil mineral N, DW, and N content of wheat [Triticum aestivum (L.) emend. Thell.] in a continuous wheat-legume rotation. Chickpeas were planted during the summer and harvested in the fall of 1992, 1993, and 1994. Vegetative growth from chickpeas was incorporated into the soil prior to wheat planting, and soil cores were taken at 35 to 48 d after chickpea harvests. Additional summer fallow treatments for the winter wheat part of the experiment received 0, 45, and 90 kg N ha^?1 each year. Wheat plants were removed the following spring and stubble was incorporated into the soil before planting chickpeas in the summer. ‘Sarah’ chickpeas accumulated about the same or more shoot DW and shoot N compared to ‘ICCV-2’; whereas ‘ICCV-2’ generally produced more pod DW and pod N compared to ‘Sarah.’ Inoculum had no significant effect on chickpea DW or N content. Wheat DW and N following legumes increased marginally after growing ‘Sarah’ chickpeas, as evidenced by higher values of some treatments. Only the multistrain or absence of inoculum in ‘Sarah’ chickpeas resulted in significantly greater wheat DW or N content compared to the fallow wheat receiving no added N fertilizer. The contributions from ‘ICCV-2’ chickpeas to wheat DW and N content were not significant. Soil mineral N, as well as wheat DW and N content, fluctuated or increased during this three-year study, which demonstrated some benefit from incorporation of chickpeas into a wheat-legume cropping system.     

Flowering and podding characteristics on the main stem of soybean grown on varying levels of phosphate nutrition 1

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.     

Changes of isoflavones during the growth cycle of Lupinus albus

The objective of this study was to monitor the changes in isoflavone content in different plant organs (leaves, stems, roots) during the crop growth stage of three cultivars of Lupinus albus (white lupin) under field conditions, taking into account sowing time effects (autumn and early spring) and cultivar effects. Three sampling dates (from late vegetative to late grain growth stages) were evaluated. Seven isoflavones and four flavonoids were identified by LC-ESI-MS analysis. The isoflavone content was higher in leaves than in stems, and it was highest before flowering, whereas it decreased during maturity. Autumn-sown plants showed higher isoflavone content than early spring-sown plants, especially in late vegetative and early reproductive stages. Genistein 7- O-glucoside was the main isoflavone of leaves and stems in the late vegetative stages of early spring sowing, whereas genistein was the main isoflavone under autumn sowing. Variation among cultivars affected only marginally the total isoflavone content. No isoflavones were detected in seeds.     

Uptake and Distribution of Arsenic in Chickpea: Effects on Seed Yield and Seed Composition

Chickpea plants were grown in arsenic (As)–contaminated soils (5 mg kg^?1 of dry soil) and investigated for As uptake, distribution, and effects on growth, yield, and quality of seeds. The roots accumulated the greatest As (7 mg kg^?1 dry weight), followed by stem (4.8 mg), leaves (4.0 mg), and seeds (0.7 mg). Arsenic inhibited the growth of the roots and shoots (as dry weight) by 65% and 60%, respectively, over controls. The shoot/root ratio declined from 4.3 in the control to 3.5 in As-treated plants. The seed yield (g) and number of pods plant^?1 decreased by 66 and 53%, respectively, over controls. A marked increase in membrane damage coupled with reduction in chlorophyll and relative leaf water content occurred in As-treated plants. The contaminated plants showed 34% and 25% decrease over control in sucrose content in their leaves and seeds, respectively. The accumulation of seed reserves such as starch, proteins, sugars, and minerals was inhibited significantly due to As-treated plants. Storage proteins such as albumins, globulins, glutelins and prolamins decreased significantly with larger effect on glutelins. The contents of minerals such as calcium (Ca), phosphorus (P), and iron (Fe) declined greatly in the seeds of As-treated plants. The accumulation of amino acids such as lysine, methionine?+?cystine, phenylalanine?+?tyrosine, proline, threonine, tryptophan, and valine was inhibited significantly in the seeds of As-applied plants compared to the control. The findings indicated that As application markedly reduced the quality of the chickpea seeds, especially in terms of proteins and minerals.     

Patterns of diversity in pigeonpea (<Emphasis Type="Italic">Cajanus cajan</Emphasis> (L.) Millsp.) germplasm collected from different elevations in Kenya

Pigeonpea germplasm accessions collected from low (<500 m), medium (501–1000 m), high (1001–1500 m) and very high elevation zones (>1500 m) of Kenya were evaluated for 15 agronomic traits and seed protein content at ICRISAT, Patancheru, India. There were significant differences (P < 0.001) among elevation zones for the number of primary and secondary branches, days to 75% maturity, pod length, seeds per pod, 100-seed weight and seed yield. Mean values indicated that the accessions from low elevation zone were significantly different from those collected in higher elevation zones for early flowering and maturity, number of primary branches, pod length, number of pods per plant, seeds per pod, 100-seed weight, seed yield and harvest index. None of the accessions collected in Kenya belonged to extra early (<80 days to 50% flowering) and early (80–100 days to 50% flowering) maturity groups, as defined by time to flowering at Patancheru, India. Mean diversity index based on all characters indicated that accessions from the low elevation zone are more diverse than those from the higher elevation zones. Frequency distribution for trait extremes indicated that the accessions from the low elevation zone were early to flower and mature, short statured, produced more primary and secondary branches with high pod bearing length, long pods, more pods per plant, more seeds per pod, a high seed yield and harvest index. Accessions from the very high elevation zone were late flowering, with a large number of tertiary branches, large seeds and a high shelling percentage and could be a source for cold tolerance and the breeding of vegetable types. Results suggest that the elevation of collection sites is therefore a very important determinant of variation patterns of pigeonpea in Kenya.     

Mineral‐nutrient synergism and dilution responses to nitrogen fertilizer in field‐grown maize

Nitrogen (N)‐fertilizer applications to field‐grown maize may result in a dilution response whereby essential mineral‐element concentrations in shoots would decrease as shoot‐dry‐matter accumulation increased. To investigate this, the effect of N‐fertilizer treatments (no N or fertilizer rate based upon 5.3 or 8.5 t ha^–1 yield goal) on maize (Zea mays L.) shoot dry weight and shoot mineral concentrations (N, P, K, S, Mg, Ca, and Mn) at the sixth leaf (V6), twelfth leaf (V12), and tassel (VT) development stages were investigated in a 2‐year study conducted at Brookings, South Dakota (USA). With increasing N‐fertilizer application rates, shoot dry weight was greater and shoot P and K concentrations decreased. A possible explanation of this dilution response is that planting‐time P and K fertilizers, which were applied in a band near the seed furrow, may have enhanced the uptake of P and K in a manner that was independent of N‐fertilizer treatments. Increased shoot‐dry‐weight production due to the application of N fertilizers, if P and K uptake were similar across N‐fertilizer treatments, would lead to decreased shoot P and K concentrations in N‐sufficient compared with N‐deficient plants. Conversely, N‐fertilizer‐induced increases in shoot dry weight were accompanied by increased shoot concentrations of N, Ca, and Mn. This synergistic response between dry‐weight accumulation and shoot N concentration was present at all leaf developmental stages studied, while that for Ca was present only at VT. Thus, N fertilizer applications that increase shoot dry weight can affect the dilution and synergistic responses of specific mineral nutrients in maize shoots. Crop developmental stage as well as the location of these specific mineral nutrients in the soil profile might play important roles in mediating these responses.     

Comparative yield and chemical composition of soybean and fababean grown on chernozemic soils on the Canadian prairies

Abstract

Soybean (Glycine max (L.) Merrill) and fababean (Vicar faba (L.)) were grown under field conditions on six Orthic Black Chernozemic soils over three years at two levels of fertility. At flowering, full pod and maturity the yield and N, P, K and S composition of harvested plant materials were compared. Application of fertilizer (P, K and S) increased dry matter and seed yields of both crops. At all, growth stages fababeans produced more dry matter than soybean, and at maturity produced higher yields of seed, hull and stalk. However, the ratio of seed: hull: stalk for both crops was similar and constant at 3.8: 1: 4.7 on all soils and at both levels of soil fertility. At the high level of soil fertility, at the flowering and full pod stages, the concentration of N, P, and K in fababean was higher than that in soybean, but both crops had a similar concentration of S. At low fertility both crops had similar concentrations of P, K and S. At maturity, soybean seed had the higher concentrations of the four nutrients. The concentration of P in the hull and stalk of both crops was similar, but fababean hull had a higher concentration of K and soybean stalk a higher concentration of S. Soybean seed also had a higher protein content and yielded more protein per hectare than fababean seed.     

Einfluß der Stickstoffernährung auf qualitative und quantitative Sameneigenschaften von Raps (Brassica napus L.)

Influence of the nitrogen-nutrition on qualitative and quantitative characteristics of seeds of rape (Brassica napus L.) An experiment was carried out under greenhouse conditions to analyse the influence of nitrogen nutrition on qualitative and quantitative characteristics of seeds of rape, variety “Erglu”. Increasing the level of nitrogen fertilization raised the crude protein content during the whole period of seed growth but decreased the lipid content during the main seed growth stages. Nitrogen nutrition only changed the fatty acid composition significantly during the early stages of seed growth. Increasing nitrogen fertilization resulted at maturity in a trend towards higher contents of palmitic and linoleic acids but in a lower content of oleic acid. At maturity the lipid content was not influenced by the level of nitrogen nutrition. The differences in seed-yield per pod between the main branch and axillary branch 5 became smaller when nitrogen nutrition was increased.     

Long-Term Effect of Nitrate Application from Lower Part of Roots on Nodulation and N2 Fixation in Upper Part of Roots of Soybean (Glycine max (L.) Merr.) in Two-Layered Pot Experiment

The long-term effect of the concentration and duration of application of nitrate from the lower part of soybean roots on the nodulation and nitrogen fixation in the upper part of roots was investigated using a two-layered pot system separating the upper roots growing in a vermiculite medium and the lower roots growing in a nutrient solution. Continuous absence of nitrate (hereafter referred to as “0–0 treatment”), and continuous 1 mM (1–1 treatment) and 5 mM (5–5 treatment) nitrate treatments were imposed in the lower pot from transplanting to the beginning of the maturity stage. In addition, 5 mM nitrate was supplied partially from the beginning of the pod stage till the beginning of the maturity stage (0–5 treatment) or from transplanting till the beginning of the pod stage (5–0 treatment). The values of the total plant dry weight and seed dry weight were highest in the 5–5 treatment, intermediate in the 1–1, 5–0, 0–5 treatments, and lowest in the 0–0 treatment. The values of the nodule dry weight and nitrogen fixation activity (acetylene reduction activity) were lowest in the 5–5 treatment. The value of the nodule dry weight in the upper roots was highest in the plants subjected to the 1–1 treatment and exceeded that in the 0–0 treatment. Total nitrogen fixation activity of the upper nodules per plant at the beginning of the pod stage was also highest in the 1–1 treatment. These results indicated that long-term supply of a low level of nitrate from the lower roots could promote nodulation and nitrogen fixation in the upper part of roots. Withdrawal of 5 mM nitrate after the beginning of the pod stage (5–0 treatment) markedly enhanced nodule growth and ARA per plant in the upper roots at the beginning of the maturity stage when the values of both parameters decreased in the other treatments. The nitrate concentration in the nodules attached to the upper roots was low, including the 5–5 treatment regardless of the stages of growth. This indicated that the inhibitory effect of 5 mM nitrate or promotive effect of 1 mM nitrate supplied from the lower roots was not directly controlled by nitrate itself, but was mediated by some systemic regulation, possibly by the C or/and N requirement of the whole plant.     

Silicon effect on growth,nutrient uptake,and yield of peanut (Arachis hypogaea L.) under aluminum stress

Abstract

The objective of this study was to investigate the effect of silicon (Si) on growth, nutrient uptake, and yield of peanut under aluminum (Al) stress. Peanut (Arachis hypogaea L. cv. Zhonghua 4) raised with or without Si (1.5?mM) in the growth chamber under 0 and toxic Al (0.3?mM) levels. Aluminum stress significantly decreased the biomass and root dry weight by 12.9% and 10.7%, and the pod yield, number of mature pod per plant and seed number of per pod by 16.7%, 10.7%, and 13.9%. The content of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) was significantly decreased, but that of Al increased markedly in shoots and roots of peanut after Al exposure at seedling, flower-needle and pod-setting stage. Under Al stress condition, Si application protected peanut by improving nutrient uptake at different growth stages and favoring the partitioning of dry mass to pod and the allocation of tissue N, P, K, Ca, and Mg to shoots and pod and decreasing Al uptake and accumulation.     

Nitrogen efficiency of grain sorghum grown on flat and raised seedbeds on poorly drained soil

Grain sorghum (Sorghum bicolor L. Moench) production commonly occurs on poorly drained clayey soils of the Mississippi River delta region inArkansas. Raised, wide seedbeds may improve grain yield and fertilizer N efficiency for narrow‐row sorghum production on these soils. The influence of individual row positions on raised, wide seedbeds was compared to conventional flat seedbed for grain yield, yield components, dry weight, and N uptake. A 193‐cm wide and 15 cm high crowned seedbed (CB) was compared to the flat seedbed (FB) in 1987 and 1988 on a Sharkey silty clay (very fine, mont‐morillonitic, nonacid, thermic, Vertic Haplaquepts) at Keiser, AR. Three rows were planted on each seedbed treatment; one in the middle of the bed and one row 48 cm to each side of the row in the middle. Nitrogen rates of 0, 56, 112, and 168 kg/ha were applied at planting. In addition, two split applications at the 168 kg/ha N rate (56 kg N/ha at planting and 112 kg N/ha at either four‐leaf or eight‐leaf growth stage) were evaluated. Each row position was evaluated for grain yield, yield components, plant dry weight, and N uptake. Whole plant samples were collected at the anthesis and physiological maturity growth stages. The field average grain yield was higher on the CB each year regardless of N rate applied at planting. This yield increase on the CB was related to the row on the top of the CB yielding more than the equivalent row on the FB. The responses of plant dry weight at each growth stage, N uptake at each growth stage, and N content of the seed was similar to grain yield responses. The split N application at planting and the eight‐leaf growth stage was as effective or better than any other treatment for increasing grain yield, N uptake, and seed N content.     

播期对高蛋白大豆新品种(系)农艺性状、品质及产量的影响

为明确高蛋白大豆新品种(系)在黄淮海区的适宜播期,本研究以黄淮海地区高蛋白大豆新品种(系)圣豆18、圣豆24、菏豆37、菏豆38为试验材料,设置不同播期试验,研究不同播期对各大豆品种(系)生育期、农艺性状、干物质积累、籽粒品质及产量的影响.结果 表明,播期推迟,出苗至始花期缩短幅度较大,大豆全生育期缩短;大豆株高、底荚...     

Effect of location on dwarf French bean (Phaseolus vulgaris L.) seed production and seedling vigour

ABSTRACT

This study examined if dwarf French bean (Phaseolus vulgaris L.) grown at northern latitudes develop seeds with superior yielding potential compared with plants grown at more southern latitudes. Two lines (BND3085 and BND3106) were grown at four sites across latitudes ranging from 52°N to 3°S. BND3085 and BND3106 seeds from Saskatoon grown plants (52°N) had the least damaged seed coats but the highest degree of electrolyte leakage from the seed and the lowest maximum germination rates. The Saskatoon (BND3085 and BND3106) and Nunhem (BND3106) seed lots had the lowest maximum germination rates when germinated at 28°C, 12°C, or when exposed to saline (100?mM NaCl) conditions. Saskatoon BND3085 seed produced plants with the lowest aboveground vegetative and total seed dry matter as well as the lowest pod number per plant. In contrast, plants grown from Saskatoon BND3106 seed produced 1.5-fold more total pods, 1.3-fold more total pods and 1.4-fold higher seed dry matter per plant as compared to plants grown from the Nunhem (51°N) or Arusha seed sources. This resulted in a 2.4–4.5% higher harvest index. These results suggest cultivar-specific dwarf French bean seed propagation at more northern sites may increase the productivity of the resulting crop.     

New oilseed rape (Brassica napus L.) varieties – canopy development,yield components,and plant density

Full exploitation of the potential of new varieties requires research, whose aim is to adapt the technology to their needs. A two-factor experiment evaluated the effect of row spacing (33, 44, and 55 cm) of three oilseed rape (OSR) varieties (conventional, hybrid, and “semi-dwarf” hybrid variety) on canopy area index (CAI) and yield components. At higher row spacing, OSR plants were characterized by a strong increase in the CAI at successive growth stages; thereby, the incomplete use of production area was compensated at the pod development stage. The differences in the CAI between row spacings were significant until the end of flowering, whereas differences in the CAI between varieties were significant until the flower bud development stage. In the next development phases, CAI of OSR plants was at a similar level to all plots. However, the statistical analysis showed a declining trend in seed yield and yield biomass (pods and straw weight) with increasing row spacing. A positive aspect of increased row spacing was a decrease in glucosinolates content in seeds. The differences in fat content were statistically insignificant. The hybrid varieties of OSR produced the highest seed yield at a row spacing of 33 cm, while the conventional – at a row spacing of 44 cm. These relationships are confirmed by high positive correlations of seed weight and pod weight per unit area with CAI. The results have important practical aspect, because it shows that it is possible to reduce the number of OSR plants per unit area, thereby reducing demand for expensive certified seeds for sowing but to certain limits. Too small plant density binds to the risk of decreased seed yield. It may be justified, e.g., in extensive or organic farming where wide row creates the possibility of mechanical weed control.     

六个生长时期高粱对NaCl胁迫的响应

为了解高粱不同生长时期对NaCl胁迫的响应机制,以高粱杂交品种济粱1号为研究材料,采用自来水(CK)和0.6%NaCl溶液(T)对萌发期、苗期、拔节前期、拔节后期、孕穗期和开花期的济粱1号进行28 d处理。结果表明,与CK相比,萌发期开始NaCl胁迫,其株高、茎粗、地上部鲜重和根干重均差异显著,相对盐害率(RSR)最大,受NaCl胁迫危害最严重。拔节前期NaCl胁迫对穗鲜重影响最显著,其次是拔节后期和孕穗期。拔节前期、拔节后期和孕穗期开始NaCl胁迫对抽穗期影响均不显著。与CK相比,萌发期、拔节后期、孕穗期和开花期开始NaCl胁迫其叶片SPAD值显著降低;与CK相比,6个生长时期进行NaCl胁迫均显著提高了叶片和根中Na⁺含量;除萌发期外,NaCl胁迫后,其他5个生长时期叶中K⁺含量显著高于CK。在6个生长时期,NaCl胁迫根中K⁺含量以及叶片和根中K⁺/Na⁺显著低于CK。因此,萌发期开始NaCl胁迫对高粱幼苗形态建成影响最大,拔节前期NaCl胁迫对穗鲜重的积累影响最显著,在...