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1.
Growth, nutrient uptake and nutrient uptake efficiency differences in orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb), and timothy (Phleum pratense L.) were evaluated at 0, 100, 200, and 300 μM Al. In each of the species, cultivar differences were also compared. In the absence of Al stress, cultivars of orchardgrass outperformed other grasses. The presence of Al reduced shoot and root growth; however, the magnitude of the growth reduction depended upon the species and cultivars. The growth of shoots and roots showed a significant difference with respect to species, cultivars, treatment Al and their Interactions. Aluminum reduced the uptake of many essential nutrients. At 100 μM Al Potomac orchardgrass had the highest and climax timothy had the lowest mineral content. The efficiency ratio (ER) assisted in classifying grass entries into efficient and inefficient utilizers of the absorbed nutrients. The ER is defined as milligrams of dry shoot weight produced per milligram of element in the shoot. The ER for P, K, Cu and Zn gave a positive correlation with shoot weight; however, in general, negative relationships were observed for shoot growth and ER for Mg, Fe, and Mn. In all the species increasing Al concentration from 0 to 100 μM increased ER for Mg and decreased ER for K and Zn. With the exception of tall fescue cultivars, the ER for P was reduced by 100 μM Al. The species and cultivars used in this study showed inter‐ and intraspecific differences in growth, uptake, and ER for nutrients in the presence or absence of Al stress. Significant reduction in growth, even at 100 μM Al by all the three species of grass indicates that these grass species are far more sensitive to Al than the field crops. Therefore, experiments with levels of Al lesser than 100 μM would have given a better outlook on the performances of these grass species.  相似文献   

2.
Toxic levels of aluminum can cause severe yield reduction in red clover (Trifolium pratense L.), especially in the presence of drought stress. Aluminum tolerances of 17 red clover cultivars and germplasms representing a broad genetic base were evaluated in a Monmouth soil [26.2% Al saturation (pH 4.8) vs. 2.8% Al saturation (pH 5.7)] and in nutrient solutions (0 vs 111 μM Al; pH 4.5). The soil and nutrient culture studies were harvested 29 and 27 d after seeding, respectively.

Aluminum stress reduced shoot and root growth significantly in soil but not in nutrient culture. Entries differed significantly in shoot vigor in both media and in root vigor in nutrient culture; responses to the two media were positively correlated. Relative weights (dry weight stressed/dry weight unstressed) in soil and nutrient culture were not correlated.

In soil, Al stress significantly reduced shoot growth of all entries except ‘Tristan’, whereas root growth was not affected significantly in ‘Atlas’, ‘Lakeland’, ‘Persist’, ‘Reddy’, ‘Redman’, or Tristan. Reddy, ‘Redland II’, Redman, and Tristan had the highest relative shoot and root weights whereas ‘Kenstar’ had the lowest. In nutrient culture, only the shoot growth of Atlas, Lakeland, Redman and ‘YKYC’ and the root growth of Redman were significantly reduced under Al stress. Atlas, ‘Kenland’, and Redman had among the lowest relative shoot and root weights and Kenstar among the highest. Some entries exhibited a positive growth response to Al.  相似文献   

3.
Phosphorus deficiency is one of the Important growth limiting factors in crop production in many regions of the world. The objective of this study was to evaluate responses of alfalfa (Medicago sativa L.), red clover (Trifoilum pratense L.), common bean (Phaseolus vulgaris L.), wheat (Triticum aestivum L.) and rice (Oryza sativa L.) to concentrations of P in nutrient solution. The P treatments applied were 5, 50, 100, 200 and 400 μM P. All crop species significantly responded to an increase in external P concentrations. The optimum P concentration for maximum growth varied with crop species, but it was higher for legumes than for cereals. Rice needs minimum as red clover maximum P concentration for maximum growth in nutrient solution as compared to other crops species. Concentrations of K, Zn and Mn were significantly affected in all crop species with P addition. Suggesting positive effects of P in ameliorating Mn toxicity if this element is present in growth medium. Increasing concentrations of P in growth medium produce negative effect on K and Zn nutrition. Growth parameters and plant nutrients concentration and uptake correlation studies showed that legumes are more responsive to P fertilization as compared to cereals.  相似文献   

4.
Abstract

Lime‐stabilized sludge (LSS) from dairy processing waste‐water treatment plants is a desirable product for land application. The material contains lime, which neutralizes soil acidity, and P, which is useful as a plant nutrient. The fineness of the lime and the solubility of P make LSS especially desirable in establishing forage legumes. This greenhouse study had two objectives: to determine a reasonable quantity of LSS for establishing forage legumes such as alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) and to prevent adverse effects on seedlings. Sludge was applied at 0, 2.5, 5.0, 7.5 g kg‐1 to an acid, low P soil in pots, and alfalfa and red clover seeds were sown. All treatments received 123 μg g‐1 potassium as KCl. A completely randomized design with four replications was used. Each species was handled as a separate study. Dry matter production was measured at one‐tenth bloom stage. Plant samples were analyzed for P, K, Ca, and Mg content. Soil samples taken at the end of the study were analyzed for pH, organic matter, Bray P, K, Ca, Mg, exchangeable Al, EC, and CEC. The higher quantities of LSS (7.5 g kg‐1 for alfalfa and 5.0 g kg‐1 for red clover) had negative effects on seedling germination and establishment. Lime‐stabilized sludge resulted in an increase in total nutrient uptake of Ca, Mg, K, and P up to 5.0 and 2.5 g kg‐1 in alfalfa and red clover, respectively. In both species significant dry matter yield increases were obtained with LSS up to 5.0 g kg‐1; however, 7.5 g kg‐1 caused a reduction in dry matter yield. Based on these results, applications of LSS at 5.0 for alfalfa and 2.5 g kg‐1 for red clover had positive effects in seedling establishment, nutrient uptake, and dry matter production. Lime‐stabilized sludge application resulted in significant increases in soil pH, available P, Ca, Mg, EC, and CEC; decreases were seen in neutralizable acidity and exchangeable Al levels in soil. This study indicates that LSS is appropriate for the acidic, low P soils of Southern Missouri for alfalfa and red clover establishment and production, if applied in appropriate quantities.  相似文献   

5.
In acid soils, Al toxicity and nutrient deficiencies are main constraints for low yield of cacao (Theobroma cacao L.). A controlled growth chamber experiment was conducted to evaluate the effect of three Al saturations (0.2, 19, and 26%) adjusted by addition of dolomitic lime on growth and nutrient uptake parameters of cacao. Overall, increasing soil Al saturation decreased shoot and root dry weight, stem height, root length, relative growth rate, and net assimilation rate. However, increasing soil Al saturation increased leaf area, specific leaf area (total leaf area/total leaf dry wt), and leaf area ratio (total leaf area/shoot+root wt). Increasing soil Al saturation decreased uptake of elements. Nutrient influx (IN) and transport (TR) decreased significantly for K, Ca and Mg, and showed an increasing trend for S and P as soil Al saturation increased. However, increasing soil Al saturation significantly increased nutrient use efficiency ratio (ER, mg of shoot weight produced per mg of element in shoot) of Ca, Mg and K and decreased ER for other elements. Reduction of soil acidity constraints with addition of lime and fertilizers appear to be key factors in improving cacao yields in infertile, acidic, tropical soils.  相似文献   

6.
Soil Aluminum Effects on Growth and Nutrition of Cacao   总被引：1，自引：0，他引：1  
In acid soils, Al toxicity and nutrient deficiencies are main constraints for low yield of cacao ( Theobroma cacao L.). A controlled growth chamber experiment was conducted to evaluate the effect of three Al saturations (0.2, 19, and 26%) adjusted by addition of dolomitic lime on growth and nutrient uptake parameters of cacao. Overall, increasing soil Al saturation decreased shoot and root dry weight, stem height, root length, relative growth rate, and net assimilation rate. However, increasing soil Al saturation increased leaf area, specific leaf area (total leaf area/total leaf dry wt), and leaf area ratio (total leaf area/shoot+root wt). Increasing soil Al saturation decreased uptake of elements. Nutrient influx (IN) and transport (TR) decreased significantly for K, Ca and Mg, and showed an increasing trend for S and P as soil Al saturation increased. However, increasing soil Al saturation significantly increased nutrient use efficiency ratio (ER, mg of shoot weight produced per mg of element in shoot) of Ca, Mg and K and decreased ER for other elements. Reduction of soil acidity constraints with addition of lime and fertilizers appear to be key factors in improving cacao yields in infertile, acidic, tropical soils.  相似文献   

7.
Seven legume extracts containing phytoestrogens were analyzed for estrogenic activity. Methanol extracts were prepared from soybean (Glycine max L.), green bean (Phaseolus vulgaris L.), alfalfa sprout (Medicago sativa L.), mung bean sprout (Vigna radiata L.), kudzu root (Pueraria lobata L.), and red clover blossom and red clover sprout (Trifolium pratense L.). Extracts of kudzu root and red clover blossom showed significant competitive binding to estrogen receptor beta (ERbeta). Estrogenic activity was determined using an estrogen-dependent MCF-7 breast cancer cell proliferation assay. Kudzu root, red clover blossom and sprout, mung bean sprout, and alfalfa sprout extracts displayed increased cell proliferation above levels observed with estradiol. The pure estrogen antagonist, ICI 182,780, suppressed cell proliferation induced by the extracts, suggesting an ER-related signaling pathway was involved. The ER subtype-selective activities of legume extracts were examined using transiently transfected human embryonic kidney (HEK 293) cells. All seven of the extracts exhibited preferential agonist activity toward ERbeta. Using HPLC to collect fractions and MCF-7 cell proliferation, the active components in kudzu root extract were determined to be the isoflavones puerarin, daidzin, genistin, daidzein, and genistein. These results show that several legumes are a source of phytoestrogens with high levels of estrogenic activity.  相似文献   

8.
Leguminous pre-crops are an important source of green manure in organic crop rotations for improving soil fertility and achieving high yields of cereals. We aimed to study the potential of various leguminous species, other than the traditionally cultivated red clover (Trifolium pratense L.), as green manure pre-crops for subsequent cereals. The use of different legume species enables to exploit advantages of specific legumes in organic cereal production. In order to test the legumes as pre-crops for cereals, we carried out trials located in the temperate climate zone of northeast Europe (58°44′59.41″ N, 26°24′54.02″ E). We sowed the following perennial legumes as pre-crops: red clover, alsike clover (Trifolium hybridum L.) and Washington lupine (Lupinus polyphyllus Lindl.), biennial white sweet clover (Melilotus albus Medik.) and annual Alexandria clover (Trifolium alexandrinum L.), and crimson clover (Trifolium incarnatum L.). Timothy (Phleum pratense L.) was used as a control. The leguminous pre-crops were followed by three spring cereals (barley, oat and spring wheat) and two winter cereals (rye and winter wheat). We tested the first-year after-effect (all cereals) and second-year after-effect (only barley and oat) of pre-crops on the grain yield of cereals. Perennial and biennial legume species produced the highest dry matter yield and contained the highest amount of nutrients, especially nitrogen, compared to annual species. All subsequent cereals produced significant extra yields after each leguminous pre-crop in the following two years, although the effect was smaller in the second year. The most suitable pre-crops for spring cereals were red and alsike clover followed by lupine, whereas the best pre-crops for winter cereals were sweet clover and annual clovers. Our results show the potential of various leguminous pre-crop species as valuable sources of green manure in organic crop rotation.  相似文献   

9.
Abstract

Toxic levels of aluminum can cause severe yield reduction in alfalfa (Medicago sativa L.), especially in the presence of drought stress. Reactions to Al stress of alfalfa cultivars and germplasms, representing a broad genetic base and the entire range of dormancy types, were evaluated in a Monmouth soil study [26.2% Al saturation (pH 4.8) vs 2.8% Al saturation (pH 5.7)] and in two nutrient solution experiments (0 vs 111 μmol Al; pH 4.5). The soil study, Experiment 1, and Experiment 2 were harvested 28, 40, and 25 d after seeding, respectively.

In all studies, entries differed significantly in vigor and yields were reduced significantly by Al stress. In the soil study, only ‘Lahontan’ was not affected significantly by Al stress, although Lahontan, ‘Atlantic’, ‘B13‐A14’ (tolerant check), ‘Ladak 65’, and ‘Mesa‐Slrsa’ had comparable relative weights (dry weight stressed/dry weight unstressed). There were no statistically significant differential responses to Al stress in Experiment 1, however the relative weight of B13‐A13 (tolerant check) was considerably larger that those of the other entries. Many entries were not affected significantly by Al stress in Experiment 2; B13‐A14, ‘Moapa 69’, ‘Saranac’, and ‘Teton’ had the largest relative weights. Relative weights for Experiment 1 and Experiment 2 were significantly correlated (r=0.46?) as was mean dry matter production in the soil study and Experiment 2 (r=0.73??).  相似文献   

10.
Ten‐day‐old seedlings of 22 rice (Oryza sativa L.) cultivars were subjected to aluminum (Al) stress in nutrient solutions with an initial pH of 4.0±0.1. The rice cultivars exhibited a wide range of response by changing the rhizosphere pH, and the uptake and efficiency ratio (ER) of utilization of nutrients both in the presence (222 μM Al) and absence of Al. In the presence of Al, the cultivars Co 37 and Basmati 370 recorded maximum uptake and highest ER's for calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P), and iron (Fe). The cultivars Damodar and ADT 36 performed very poorly in terms of nutrient uptake. The tolerant cultivars (Al‐insensitive) efficiently took up and utilized Ca and P in the presence of Al. The susceptible (Al‐sensitive) and intermediate cultivars exhibited less Ca and P uptake and utilization. There was no apparent relationship between foliar Al content and the efficiency ratios. However, the Al‐tolerant cultivars, Co 37 and Basmati 370, accumulated less Al in their foliage which was the reverse in case for the Al‐susceptible cultivars. Among the 22 rice cultivars tested, Co 37 and Basmati 370 emerged as the most Al‐tolerant. Hence, they would be recommended for cultivation in acidic, infertile soils of the tropics. The results of this study are discussed in terms of identifying the mechanism of Al tolerance or sensitivity among the studied rice cultivars as related to their nutrient metabolism.  相似文献   

11.
A study was conducted to evaluate the effects of aluminum (Al) in nutrient solutions on the dry weight (DW) yield, Al and phosphorus (P) contents, and organic acid exudation in alfalfa (Medicago sativa L.). Four alfalfa cultivars (‘Robust’, ‘Sceptre’, ‘Aquarius’, and ‘California-55’) were grown in nutrient solution at pH 4.5 and 6.0, with (50 and 100 μM) and without Al. The results revealed that Al caused a significant reduction in DW, especially in pH 4.5 treatment. Organic acid exudation was affected by pH and Al treatments. Citrate and succinate exudation increased with the high Al treatment at pH 4.5. However, no relationship between pH and carboxylate exudation was observed at pH 6.0. Accumulation of P and Al in roots suggests the existence of an exclusion mechanism for Al in alfalfa. Selection of cultivars with enhanced organic exudation capacity in response to Al might be useful for alfalfa production in moderately acidic soils.  相似文献   

12.
A major constraint to the renovation of forage legume‐based pastures on acidic soils of the Appalachian hill‐lands is thought to be the absence of effective rhizobia. A growth chamber experiment was done with aluminum (Al) toxic, low pH (≥ 4.2) soils from four series (Berks, Lily, Tate, and Westmoreland) that were planted with alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), white clover (Trifolium repens L.), or birdsfoot trefoil (Lotus corniculatus L.). These soils, without lime addition, were previously shown not to contain effective, naturalized populations of rhizobia for these plant species. However, a non‐toxic, pH 6.8, Watauga soil was shown to have such rhizobia but only for alfalfa. In the present study, these five soils were reexamined after liming to pH ≥ 5.5 for effective, naturalized populations of rhizobia and the efficacy of soil inoculation with commercially available rhizobia. In addition to effective, naturalized R. meliloti for alfalfa in the Watauga soil, similar populations of R. trifolii for red clover, and R. lotus for birdsfoot trefoil, were now found. Such rhizobia were also found for alfalfa in the Lily soil and for red clover in the Lily and Tate soil. Thus, liming allowed the expression of effectiveness of natural rhizobia that otherwise would not have been detected in soil pot experiments without lime. Inoculation of the toxic soils after lime addition with commercial rhizobia was effective in about half of the soil‐plant combinations that did not contain populations of effective, naturalized rhizobia. Asymbiotic shoot growth of all the plant species was significantly (P ≤ 0.05) correlated with soil pH over a range of 5.5–6.6. These results indicate that, in the absence of effective, naturalized populations of rhizobia, improvement of rhizobial inocula could increase forage production by ～34% for some species on some of the toxic soils, even after the pH of the soils is increased to ≥ 5.5.  相似文献   

13.
A new approach for determining optimum nutrient element ratios in plant tissue is presented. Essential steps in the procedure involve: a) measuring patterns of response to pairs of nutrient elements in factorial fertilizer trials, b) modeling the yield response surface using a bivariate, Mitscherlich‐related response function, c) defining balanced nutrition in terms of the parameters of the response surface, d) identifying combinations of P and S fertilizer resulting in balanced nutrition, and e) determining from plant chemical analysis the ratio of nutrients in plant tissue in nutritionally balanced combinations. The approach is illustrated by data from a phosphorus (P) by sulfur (S) factorial field fertilizer trial on a mown mixed white clover (Trifolium repens cv Grasslands Huia) and ryegrass (Lolium perenne L cv Grasslands Nui) sward. Different parameters of yield [total dry matter production, clover dry matter production, clover nitrogen (N) uptake] required different ratios of S:P in fertilizer and consequently in plant tissue for nutritional balance. Also, plant tissue S:P ratios for balanced nutrition declined as the level of nutrition increased. Economic optimum S:P fertilizer ratios were higher than those ratios required for nutrient element balance due to the lower cost and higher effectiveness per kilogram of fertilizer S compared with fertilizer P. Ratios of S and P to N in clover tissue were useful indicators of the adequacy of S and P for clover which was dependent on N2 fixation for its N supply. It is suggested that a nutrient element index system showing both relative and absolute nutrient element status might be built around N as an internal standard for legumes dependent on N2 fixation and possibly also for non‐legumes.  相似文献   

14.
Bermudagrass (Cynodon dactylon L.) is a warm season perennial that is well adapted in the southern Great Plains. It is one of the region's most important forage crops used for livestock production, and is commonly grown without legume interseeding. Recent research has investigated ways of improving the quality and quantity of this forage. The objectives of this study were to determine the effect of interseeded legumes and phosphorus (P) fertilizer on bermudagrass pasture forage yield and crude protein content. One experiment was initiated in 1993 in eastern Oklahoma in an established bermudagrass pasture. Red clover (Trifolium pratense L.), ladino clover (Trifolium repens L.), and two varieties of alfalfa (Medicago sativah), ’alfagraze’ and'common’, were interseeded by hand into an established stand of bermudagrass. The effect of P on forage yield and crude protein was evaluated using a 30‐kg P ha‐1 rate applied at establishment versus no applied P. Forage yield was collected three times throughout the growing season each year from 1994 through 1997. When both alfalfa varieties were interseeded into a bermudagrass pasture without applying additional P fertilizer, forage yields for the legume‐grass mixtures decreased below those obtained from the monoculture bermudagrass in the first year of the stand. The alfalfa variety ‘alfagraze’ interseeded into established bermudagrass decreased total forage yield over the entire 4‐yr study. Interseeded red clover and ladino clover increased crude protein of the forage compared with monoculture bermudagrass the first two years of the study, with red clover continuing to increase crude protein in the fourth year. However, when 30 kg P ha‐1 was applied to the bermudagrass prior to establishment of the legumes, no change in yield or protein was observed for both alfalfa varieties’ interseeding treatments versus the unfertilized mixtures. Although forage yield may not be increased, interseeding legumes into established bermudagrass could provide an efficient way to improve pasture crude protein without the use of inorganic fertilizers. However, if alfalfa ('common’ or ‘alfagraze') is interseeded, additional P may need to be applied at legume establishment to prevent possible yield decreases.  相似文献   

15.
Low supply of nutrients is a major limitation of forage adaptation and production in acid soils of the tropics. A glasshouse study was conducted to find differences in plant growth, nutrient acquisition and use, among species of tropical forage grasses (with C4 pathway of photosynthesis) and legumes (with C3), when grown in two acid soils of contrasting texture and fertility. Twelve tropical forage legumes and seven tropical forage grasses were grown in sandy loam and clay loam Oxisols at low and high levels of soil fertility. After 83 days of growth, dry matter distribution among plant leaves, stems, and roots, leaf area production, shoot and root nutrient composition, shoot nutrient uptake, and nutrient use efficiency were measured. Soil type and fertility affected biomass production and dry matter partitioning between roots and shoots. The allocation of dry matter to root production was greater with low soil fertility, particularly in sandy loam. The grasses responded more than the legumes to increased soil fertility in both shoot and root biomass production. Leaf area production and the use of leaf biomass for leaf expansion (specific leaf area) were greater in legumes than in grasses, irrespective of soil type and fertility. But soil type affected shoot biomass production and nutrient uptake of the grasses more than those of the legumes. There were significant interspecific differences in terms of shoot nutrient uptake. The grasses were more efficient than legumes in nutrient use (grams of shoot biomass produced per gram of total nutrient uptake) particularly for nitrogen (N) and calcium (Ca).  相似文献   

16.
《Journal of plant nutrition》2013,36(6):1335-1343
Abstract

Many alternative management systems have been evaluated for corn (Zea mays L.), soybeans (Glycine max L.), and wheat (Triticum aestivum L.) production, however, most have involved rotations from one year to the next. Legume interseeding systems which employ canopy reduction in corn have not been thoroughly evaluated. One such study was initiated in 1994 at the Panhandle Research Station near Goodwell, OK, on a Richfield clay loam soil, to evaluate five legume species interseeded into established corn: yellow sweet clover (Melilotus officinalis L.), subterranean clover (Trifolium subterraneum L.), alfalfa (Medicago sativa L.), arrowleaf clover (Trifolium vesiculosum L.), and crimson clover (Trifolium incarnatum L.). In addition, the effect of removing the corn canopy above the ear (canopy reduction) at physiological maturity was evaluated. Canopy reduction increased light interception beneath the corn thus enhancing legume growth in late summer, early fall, and early spring the following year prior to planting. Forage growth from legumes incorporated prior to planting were expected to lower the amount of inorganic nitrogen (N) fertilizer needed for corn production. Crimson clover appeared to be more shade tolerant than the other species, and interseeding this species resulted in the highest corn grain yields when no N was applied. In the last two years, interseeding crimson clover at physiological maturity, followed by canopy reduction resulted in a 1.32 Mg ha?1 increase in yield compared to conventionally grown corn with no N applied. In 1999, interseeded legumes (except subterranean clover) in conjunction with the application of 56 kg N ha?1 and crimson clover interseeded without the addition of fertilizer N (with and without canopy reduction) resulted in grain N uptake levels equal to the 112 kg N ha?1 treatment.  相似文献   

17.
Crimson clover (Trifolium incarnatum L.) plus hairy vetch ( Vicia villosa Roth), red clover (Trifolium pratense L.), white clover (Trifolium repens L.), red clover plus white clover, and bermudagrass (Cynodon dactylon [L.] Pers.) were evaluated as cover crops for pecans. Crimson clover plus hairy vetch supplied the equivalent of 101 to 159 kg nitrogen (N)/ha. Red clover plus white clover supplied up to 132 kg N/ha. Either white clover or red clover alone were less effective in supplying N than when grown together. Soil Kjeldahl‐N was usually not affected or increased using the legumes compared to fertilized bermudagrass sod. Soil nitrate (NO3) concentrations during October were occasionally higher in unfertilized legume plots than in bermudagrass plots with March‐applied N.  相似文献   

18.
Toxic levels of aluminum can cause severe yield reductions in many crop species, but sericea lespedeza [Lespedeza cuneata (Dum.‐Cours.) G. Don] has demonstrated considerable tolerance. Aluminum tolerances of six sericea lespedeza cultivars (Am 312, Appalow, AU Lotan, Interstate, Interstate 76, Serala) representing a broad genetic base were evaluated in a Monmouth soil [26.2% Al saturation (pH 4.8) vs. 2.8% Al saturation (pH 5.7)] and in nutrient solutions (0 vs 111 μM Al; pH 4.5). The soil and nutrient culture studies were harvested 30 and 27 d after seeding, respectively.

Aluminum stress did not reduce root and shoot growth significantly, nor were the pooled Al stress x cultivar interactions significant. Cultivars differed significantly in mean shoot and root vigor in nutrient solutions but not in soil. R‐esponses in soil were only weakly correlated with responses in nutrient solutions. Am 312 and Appalow had the lowest relative weight values (dry weight stressed/dry weight unstressed) in both media and Interstate and Interstate 76 the highest. Interstate 76 exhibited a significant positive response (5% level) to Al when evaluated in nutrient solutions.  相似文献   

19.
Na_2SO_4和NaHCO_3对生菜生长的影响   总被引：1，自引：0，他引：1  
研究了营养液中不同浓度Na2 SO4 和NaHCO3处理对生菜生长的影响。结果表明 ,随着两种盐浓度增加 ,生菜叶面积和地上部干重逐渐减小 ;NaHCO3处理对地上部生长的抑制更显著。Na2 SO4 处理植株吸水量降低 ,表明存在渗透逆境 ;NaHCO3处理植株吸水量不受影响 ,但营养液pH值增加迅速。生菜品种L 2比P对盐胁处理更敏感。  相似文献   

20.
This study was conducted in Prince Edward Island (P.E.I.), Canada to characterize the levels of B, Mo, and Se in the various plant parts of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), broccoli (Brassica oleracea var. italica Plenck.), Brussels sprouts (Brassica oleracea var. gemmifera Zenker), cauliflower (Brassica oleracea var. botrytis L.), and rutabaga (Brassica napobrassica Mill). The three micronutrient anions were consistently highest in the leaves and lowest in the stems. The lower halves of the vegetable crops usually contained close to the highest amounts of B and Mo. In forage legumes, the B concentration was higher in the bottom than in the upper leaves, but B was lower in the bottom than upper stems. Since leaves consistently contained the highest amounts of B and Mo, it is recommended that most recently matured leaves in the Brassica species, and young leaves in forage legumes be sampled to characterize the B and Mo status of these crops. Selenium is of significance to livestock, but not in plant nutrition; therefore, only the parts fed to animals, e.g. the whole vegetative tops of forage legumes, should be used to determine the crop Se status.  相似文献   

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