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1.
Abstract

Boron (B) deficiency symptoms, dry matter production, and B critical values in sesame (Sesamun indicum L.) were investigated in a greenhouse experiment. Boron deficiency showed a yellowing of plant tops and of the youngest leaves. Upper leaves became dark green, coriaceous, with edges curved down. Boron‐deficiency symptoms was related to 21 μg B/g in the 30‐day‐old youngest fully expanded leaf. Dry matter production of leaves, stems, pods, and roots were severely decreased when B in the leaf tissue was below 21 μg/g; however seed dry weight and seed oil content were associated to less than 39 μg/g of B in the leaf tissue.  相似文献   

2.
Boron deficiency symptoms in snap beans (Phaseolus vulgaris L.) showed as general yellowing of tops with slow flowering and pod formation, while toxicity caused reduced growth and burned dark brown older leaves especially on the edges. In radish (Raphanus sativus L.)f B deficiency resulted in roots which were brown upon cutting and had thick periderm. Even at 4 ppm applied B, no visible B toxicity was noted in radish. The plant tissue B levels of less than 9 to 12 ppm were associated with B deficiency in radish and beans; and greater than 125 ppm with B toxicity in beans. In tomatoes (Lycopersicon esculentum, Mill) B deficiency resulted in reduced growth while B toxicity at 4 ppm applied B caused poor and slow germination. Boron deficiency and toxlcity in tomatoes were related to < 12 and > 172 ppm B, respectively, in tissue. No B deficiency was noted in corn (Zea mays L.) and timothy (Phleum pratense L.). The B toxicity in these two crops appeared as marginal burning and dark brown tips of older leaves and was related to greater than 98 and 176 ppm tissue B in corn and timothy, respectively.  相似文献   

3.
Abstract

The tolerance of rice (Oryza sativa L. C.V. Earlirose) to various trace metal excesses was tested to determine if high levels of the trace metals found in some field‐grown plants were at toxicity levels. In one experiment, levels of 2200 μg Zn/g dry weight, 44 μg Cu/g dry weight, 4400 μg Mn/g dry weight, and 32 μg Pb/g dry weight in shoots of young plants had no adverse effects on vegetative yields. A level of 3160μgZn/ g dry weight decreased yields about 40% (P = . 05). In another test 51 μg Cu/g dry weight or 94 μg Pb/g dry weight did not decrease vegetative yields. Boron supplied at 10‐3 MH3BO3 not only caused no toxicity but resulted in only 144 μg B/g dry weight in shoots. Root levels of Zn were about equal to those in shoots; Mn levels were lower in roots than in shoots (1/4 to 1/10); B levels were generally low in both shoots and roots with roots 1/10 that of shoots; Cu levels were higher in roots than in shoots. Rice was tolerant of a high level of Cr. The tolerance of rice to high levels of some trace metals in these experiments may be related to high P levels in plants.  相似文献   

4.
Root active uptake and remobilization of boron (B) have been accepted as mechanisms contributing to nutrient efficiency under low supply of boron. Here, we examined the existence of these mechanisms in eggplant (Solanum melongena L.) supplied either with luxury (100 μM, B+) or low (7.5 μM, B–) B in the growth medium via semihydroponic cultivation. Boron treatment was marginally not limiting growth thus avoiding side‐effects and impairment of acclimation mechanisms of plants. The induction of a B‐concentrating mechanism was evident in the roots as B concentration in the xylem sap was only decreased by 23% in B– compared to B+ plants, i.e., B– roots concentrated B by a factor of 2.7 relative to the external solution. Leaf B concentration in the B– treatment decreased by 33% and 40% in young fully expanded and mature leaves, respectively. Larger differences were observed in the soluble B fraction that decreased by 65% in mature leaves. However, both total and soluble B concentrations in developing leaves were almost equal for both treatments exhibiting a pattern commonly observed in B‐remobilizing plants. On the other hand, amounts of B export in the phloem sap were small compared to other species in which B is highly mobile. The B export rate from source leaves was slightly increased under low B supply while that of sucrose was not affected. We conclude that the root concentrating mechanism contributes to the alleviation of B deficiency in eggplant under low B supply while B remobilization may also contribute to a lower degree.  相似文献   

5.
Since the early 1990s canola (oilseed rape, Brassica napus L.) has become a major crop species grown on the predominantly sandy soils of southwestern Australia. Numerous studies have been undertaken to determine the fertilizer requirements of the crop in the region. This paper reports results of a field experiment conducted at three sites on typical acidified (pH [Ca] ～4.6) sandy gravel soils to identify if molybdenum (Mo), manganese (Mn) or boron (B) were deficient for canola grain production. Different levels of each element, separately or as mixtures, were applied as foliar sprays at mid-flowering. Maximum grain yield responses of ～11–20% to applied Mo, as sodium molybdate (39% Mo), were obtained when 40 g Mo/ha was applied. Maximum grain yield responses of ～13–28% to applied Mn were achieved by applying 1000 g ha?1 Mn, as manganese sulfate (24% Mn). A mixture of 40 g Mo ha?1 and 1000 g Mn ha?1 increased grain yields by ～15–38%. Boron, applied as borax (11% B), sprayed individually or in combination with Mo or/and Mn, had no effect on grain yields. None of the foliar spray treatments had any effect on oil concentration in canola grain. The sprays did not cause any visible damage to foliage. Soil acidification has been shown to induce Mo deficiency for cereal crops in the region and both soil acidification and induced Mo deficiency are alleviated by applying sufficient lime to raise pH of top 10 cm soil to 5.5 or greater, and this strategy should also apply to canola. Further research is required to determine the fertilizer Mn requirements for canola grain production in the region.  相似文献   

6.
Abstract

Boron (B) deficiency is common in some cotton (Gossypium hirsutum L.) growing regions of the world. A better understanding of changes in the growth and physiological characteristics of cotton plants during the development of B deficiency will help us to define field diagnosis techniques and improve B fertilizer management recommendation. An experiment was conducted in a controlled‐environment growth chamber to determine effects of B deficiency during early vegetative growth on leaf photosynthesis, plant dry matter accumulation, photosynthetic assimilate partitioning, and other physiological parameters. Boron deficiency considerably decreased leaf net photosynthetic rate, plant height, leaf area, fruiting sites, and dry matter accumulation during squaring and fruiting. Depressed photosynthesis and plant growth (especially fruits and roots) resulted in increased fruit abscission and changes in dry matter partitioning among plant tissues. The results help explain effects of B deficiency on suppression of cotton growth and yield and provide information for improving the diagnosis of B deficiency in cotton production.  相似文献   

7.
The effect of aluminium (Al) on the relative yield of plants grown from seeds of ryegrass (Lolium perenne L.) or white clover (Trifolium repens L.) and either tillers (ryegrass) or stolon tip cuttings (white clover) were investigated using a low ionic strength (2.7 x 10‐3 M) solution culture technique. In ryegrass, plants grown from tillers had higher relative yields than plants grown from seedlings in the tops when solution Al concentrations were greater than 16 μM and in the roots when solution Al concentrations were greater than 7 μM. In white clover, relative yields in the tops and roots plants were higher in plants grown from stolon tip cuttings than from seedlings when solution Al concentrations were greater than 10 μM. There were no significant cultivar effects. The results indicate that plants used in Al‐tolerance experiments can be grown from seed or vegetatively propagated, provided solution Al rates are adjusted to reflect differences in Al tolerance.  相似文献   

8.
Boron (B) foliar treatments (300 mg L?1 as Solubor DF) were applied at two different dates in 2006 and 2007, prior to flowering and just after fruit set, on olive (Olea europaea L.) trees with no visual symptoms of B deficiency. Leaf B level increased after the first application as compared to control (?B). After July treatment, leaf B levels in ?B and +B treated trees increased when compared to the first sampling date. Foliar B application did not significantly affect vegetative growth in either year. During the first year of study (considered as an “on year”), B application had no significant effect on several phenological characteristics including fruit set, yield oil contents and oil quality. In the second year (“off year”), B sprays improved blooming rate, which increased from 20% in ?B to 30% in + B treated trees, and olive yield, which increased by 27% in response to B.  相似文献   

9.
Boron (B) amelioration of aluminum (Al) toxicity was studied for growth of mungbean (Phaseolus aureus Roxb.) seedlings and cuttings (without roots) in a growth chamber. Mungbean seedlings and cuttings were grown in the solution with combinations of three concentrations of B (0,5, and 50 μM) and three concentrations of Al (0, 2, and 5 mM) in randomized complete block design experiments for 16 days. Results showed that B significantly promoted elongation of epicotyls and hypocotyls, and increased height of seedlings grown under Al stress. Boron also increased fresh weight of seedlings in high Al solution. Treatment of plants grown with high B and Al stress had no apparent effect on fresh and dry weights of seedling roots. Seedling dry weight increased significantly by adding high B to solutions with 2 mM or 5 mM Al. No significant differences were observed between the high B treatment and the control (normal B, 5 μM) in lengths of epicotyls and fresh and dry weights of mungbean cuttings grown under Al stress. High concentrations of B decreased soluble protein and increased chlorophyll in seedlings treated with 2 mM Al. Boron had no amelioration effect on cuttings grown with Al, although Al increased soluble protein. Our results suggested that B alleviation of Al toxicity was related to root function and Al toxicity may possibly be due, in part, to B deficiency.  相似文献   

10.
Boron (B) deficiency frequently occurs on soils that are low in organic carbon (C) (<1.0% organic C), pH (soil pHCa <5.0), and clay content (<5% clay). Acid sands with these soil properties are common in south-western Australia (SWA). Moreover, hot calcium chloride (CaCl2) extractable B levels are commonly marginal in the acid sands of SWA. This study examined the effects of soluble and slow release soil-applied B fertilizer and foliar B sprays on crops most likely to respond to B fertilizer on these soils, canola (oil-seed rape, Brassica napus L.) and lupin (Lupinus angustifolius L.).

At 25 sites over three years, canola was grown with (0.34 kg ha-1) or without B applied as borax [sodium tetraborate decahydrate (Na2B4O7·10H2O) 11% B], and this was followed by nine experiments with B rates [0, 0.55, 1.1 kg ha?1, applied as borax or calcium borate (ulexite, NaCaB5O6(OH)6·5(H2O), 13% B] and foliar sprays (0.1% solution of solubor, 23% B) in 2000–2001. A further five sites of B rates and sources experiments were carried out with lupin in 2000–2001. Finally, foliar B sprays (5% B w/v as a phenolic complex) at flowering were tested on seven sites in farmers’ canola crops for seed yield increases. No seed yield increases to soil-applied B were found while foliar B application at flowering increased canola seed yield in only one season across seven locations. By contrast, borax fertilizer drilled with the seed at sowing decreased canola seed yield in nine of 34-farm sites, and decreased lupin yield in two of five trials. Toxicity from drilled boron fertilizer decreased yield could be explained by decreases in plant density (by 22–40%) to values lower than required for optimum seed yield. Seedling emergence was decreased by borax applied at sowing but less so by calcium borate. Foliar B spray application never reduced seed yield due to toxicity effects.

Boron fertilizer drilled with the seed increased the B concentration in plant dry matter at early to mid-flowering. Boron application decreased the oil concentration of grain of canola at four sites. The oil yield of canola was significantly decreased at seven sites.

Notwithstanding the marginal B levels on acid sands of the SWA region, care needs to be taken on use of borax fertilizer as toxicity was induced in canola and lupin; with 0.34 to 1 kg B ha?1(3-10 kg borax ha?1) at sowing depressing seed yield, mostly by decreasing plant density. Rather than making general recommendation for B fertilizer application based on 0.01M CaCl2 soil extractable B, soil and plant analysis should be used to diagnose B deficiency and B fertilizer use limited to calcium borate or foliar borax rather than soil-applied borax on low B sands.  相似文献   

11.
The effect of varying solution calcium (Ca) and magnesium (Mg) concentrations in the absence or presence of 10 μM aluminum (Al) was investigated in several experiments using a low ionic strength (2.7 × 10‐3 M) solution culture technique. Aluminium‐tolerant and Al‐sensitive lines of wheat (Triticum aestivum L.) were grown. In the absence of Al, top yields decreased when solution Ca concentrations were <50 μM or plant Ca concentrations were <2.0 mg/g. Top and root yields decreased when solution Mg concentrations were <50 μM or plant Mg concentrations were <1.5 mg/g. There were no differences between the lines in solution or plant concentrations at which yield declined. Increasing solution Ca concentrations decreased plant Mg concentrations in the tops (competitive ion effect) but increased plant Mg concentrations in the roots of wheat. This suggests that Ca is competing with Mg when Mg is transported from the roots. Increasing solution Mg concentrations decreased plant Ca concentrations in the tops and the roots (competitive ion effect). In the roots, increasing solution Mg concentrations decreased plant Ca concentrations at a lower solution Ca concentration in the Al‐sensitive line than the Al‐tolerant line. In the presence of Al, increasing solution Ca and Mg concentrations increased yield (Ca and Mg ameliorating Al toxicity). Yield increased until the sum of the solution concentrations of the divalent cations (Ca+Mg) was 2,000 μM for the Al‐tolerant line or 4,000 μM for the Al‐sensitive line. The exception was that yield decreased when solution Mg concentrations were > 1,500 μM and the solution Ca concentration was 100 μM (Mg exacerbating Al toxicity). The ameliorative effects of solution Ca or Mg on Al tolerance were not related to plant Ca or Mg concentrations per se.  相似文献   

12.
Boron (B) deficiency is potentially an important nutrient constraint in calcareous soils. We determined B deficiency incidence and spatial distribution in rainfed wheat (Triticum aestivum L.) in 1.82 Mha Pothohar plateau in Pakistan, its relationship with soil types, crop responses to B, and internal B requirement and B fertilizer use efficiency of wheat. Plant and soil analyses indicated deficiency in 64% of the 61 sampled fields; geostatistics-aided contour maps delineated B deficient areas. In rainfed field experiments, B use increased wheat yields up to 11%. Fertilizer requirement was 1.2 kg B ha?1; critical B concentration (mg kg?1) ranges were: young whole shoots, 4–6; flag leaves, 5–7. Boron uptake by wheat was 0.14–0.58% of applied dosage, leaving substantial residual impact. Highly cost-effective B use or B-efficient genotype adoption can enhance wheat productivity and grower-income. Such effective nutrient assessment and management approaches can be beneficially adopted elsewhere as well.  相似文献   

13.
Iron‐efficient T3238FER tomatoes (Lycopersicon esculentum Mill.) did not respond to Fe‐deficiency stress by releasing hydrogen ions and reductants from their roots when the plants were grown in a K‐deficient nutrient solution with or without sodium. When increments of K were added to the nutrient solution, the plants responded proportionally to Fe‐deficiency stress, Fe was transported to plant tops and the chlorophyll concentration in plant tops increased. As the leaf Fe concentration was increasing, root K concentration was increasing and root Mn concentration was decreasing. The K and Mn in tops did not show the marked differences observed in roots.

In the presence of adequate K, renewing the solutions each time the pH was lowered to near 4 (days 7 and 11) caused an increased concentration of most elements in the plant, especially Mn in both tops and roots. These plants had the same Fe concentration as plants grown in unchanged solutions but they contained much less chlorophyll. Balance of nutrient elements to some degree seems required in order for iron to be made available to function properly in the plant.  相似文献   


14.
A sensitive measure of growth in the duckweed, Lernna minor, was used to demonstrate the tolerance of this higher plant to boron [B(OH)3] at levels of 10 to 20 μg/mL in the growth medium at pH 5.0. Growth inhibition by B in concentrations up to 100 μg/mL in the external medium was reversible after transfer to control medium. At pH 4.0 and in the presence of 20 μg/mL B for 7 days, the plants accumulated 93 μg B/g fresh weight (148% of the control) and this increased with pH up to pH 7.0 where the plants accumulated 257 μg B/g fresh weight (525% of the control). Only at pH 7.0 in the presence of B was growth inhibited. Thus, plants which had accumulated more than 100 μg B/g fresh weight still grew normally. This corresponds to about 800 μg B/g dry weight accumulated by this monocot without effect upon growth rate.  相似文献   

15.
When carrots (Daucus carota L.) are mechanically harvested, sufficient nitrogen (N) must be balanced between the roots and carrot tops; weak tops reduce yield. A 2-year study was conducted in Montcalm County, Michigan, where four replications of four N treatments (45, 90, 135, and 180 kg ha?1), were arranged in a randomized complete block design. Results showed the importance of determining pre-existing N sources, in as much as the deep taproot of carrot accessed unmeasured N in the subsoil and nitrate concentrations in irrigation water added N. The greatest yield occurred at 153–189 kg ha?1 available N while tops continued to take up N through 200–232 kg ha?1. When the last N application was made less than 35 days before harvest, the rate of N uptake exceeded dry-matter accumulation rate.  相似文献   

16.
Abstract

Boron applied in 2 soybean field experiments at rates up to 2.12 kg/ha was not detectable in Ap or B2 horizon soil extracts approximately 6 weeks after B addition, although leaf B contents reflected added B. There was a measurable difference between the 2 fields in extractable B. Where the Ap horizon averaged 0.05 ppm B, soybean leaf content ranged 14 to 40 ppm B and no yield response was obtained with 0.56 to 2.24 kg/ha of added B. Where the Ap horizon averaged 0.11 ppm B, and leaf content reached 63 ppm B, soybean yield was reduced approximately two‐thirds by 2.24 kg/ha of added B.

Data from these 2 field experiments and previous micronutrient field studies, where yield response to B fertilization was obtained when leaf B was 9 to 10 ppm in soybean leaves, suggest that plant tissue analyses for B can be used to evaluate B fertilization needs. Soil tests may not be useful for detecting B deficiency in coarse‐textured soils, but may aid in detection of areas where B levels are high.  相似文献   

17.
Although boron (B) deficiency in chestnuts (Castanea sativa Mill.) has been identified in Portugal and B fertilization was carried out in some orchards, the post-treatment evaluations have not been made to date. So the objective of this trial was to confirm the B deficiency and to quantify the effect of B applications to the soil on nut yield and quality. In October 2006, a fertilizer trial was established in a 15 year-old orchard in a very acid soil derived from siliceous schists. Soil liming and a basal fertilization were carried out in 16 trees and two levels of sodium tetraborate (Granubor, 14.6% B) were applied to eight trees: control (B0) and 100 g of Granubor per tree (B1). In the beginning of September chestnut leaves were collected from five trees and analyzed for macro- and micronutrients. Nut productivity was measured per tree and some nut quality parameters were evaluated, including the chemical composition of the kernel (soluble sugars, starch, total fiber, crude protein, and crude fat) in 2007, and dry matter, nut caliber, and fruit damage in 2007 and 2008. Boron fertilization of chestnuts significantly increased nut production: 75% in the first year (8 kg and 14 kg per tree, respectively, in the B0 and B1) and, in the second year, was over four times higher (4 kg and 17 kg per tree, respectively, in the B0 and B1). No significant differences were found in dry matter, nut caliber, nut damage and chemical composition of the kernel in the first year, but in the second year lower fruit damage by chestnut tortrix (P<0.0089) was observed. Foliar analyses exhibit relatively low B concentrations in the control trees (average value of 8 mg kg?1) in both years, while in the fertilized trees the foliar B concentration were in average 61 mg kg?1 in the first year, and 34 mg kg?1 in the second year. The large drop in the foliar B concentration in the second year suggests the need to monitoring the nutrient status of chestnut orchards or more frequent of B application than usual practice.  相似文献   

18.
Boron deficiency is a major production constraint of Mango cv Alphonso in western coast, Maharashtra, India. The soils are sandy-loam, light, acidic in reaction and receive high annual precipitation of above 2,500 mm. The leaf and soil B status was low with an average of 23 and 0.25 mg kg−1 respectively. About 60% of the orchards were found to be deficient in B. The B adsorption study using Langmuir adsorption isotherm revealed that the adsorption capacity of B by these soils was low with an average adsorption maxima (b) of 16.62 μg g−1 and bonding energy constant ( K ) of 0.09 mL μg−1 making soil B susceptible to leaching. The Mango leaf N status was in excess range, which aggravated B deficiency through growth dilution. A significant negative correlation was observed between leaf B and leaf N (statistically significant at 1% level (p=0.01)). The free Al status of the soils was found to be fairly high, and its detrimental effect on root growth was observed which led to inefficient absorption of limited soil B by roots. The climatic conditions of Konkan like high humidity, high temperature and long sunshine hours also favored widespread incidence of B deficiency, low yield and poor quality. The response of Mango cv Alphonso to the B application was found to be more in foliar than in soil application.  相似文献   

19.
Row crops such as potatoes (Solanum tuberosum L.) and carrots (Daucus carota L.) are of high economic value in the Nordic countries. Their production is becoming more and more specialized, including continuous arable cropping and heavier farm machinery, with increased risk of soil compaction. The result may be restricted root development and economic losses. Potatoes have widely branched adventitious roots, whereas carrots have taproots with fibrous roots extending from them. Under optimal soil conditions, total root length per surface area may reach more than 10 km m?2 for both species. Maximal root depth is about 140 cm for potato and more than 200 cm in carrots. Most of the root mass is usually distributed within the upper 100 cm, whereof more than 50% may be deeper than 30 cm. Soil compaction causes a dense soil with few large pores, poor drainage and reduced aeration, especially in wet soils with low organic matter content and high proportions of silt or clay. With compacted subsoil layers, roots will be concentrated more in the upper layers and thus explore a smaller soil volume. This will lead to reduced water and nutrient uptake, reduced yields and low nutrient utilization efficiency. In this review article, we describe the interactions between root development and soil conditions for potatoes and carrots, with special focus on sub-optimal conditions caused by soil compaction. We also discuss the effects of tilling strategies, organic material, irrigation and fertilization strategies and controlled traffic systems on root and yield development. To reduce subsoil compaction there is a need to implement practises such as controlled traffic farming, new techniques for ploughing, better timing of soil operations, crop rotations with more perennial crops and supplements of organic material. Moreover, there is a need for a stronger focus on the impacts of farm machinery dimensions.  相似文献   

20.
Abstract

Earlirose rice (Oryza sativa L. ) and Hawkeye soybeans (Glycine max L.) were grown in solution culture with A12(SO4)3 in concentrations of 0, 10‐6, 10‐5, 10‐4, 10‐3 M. Only at 10‐4 (slightly) and at 10‐3 M were there yield depressions due to Al. The threshold concentration of Al for toxicity was about 20 μg/g in rice shoots and about 30 μg/g in soybean leaves. The solution level necessary for these concentrations was 8 μg Al/ml. Plant concentrations which caused severe toxicity were 70 μg Al/g plant with 81 μg Al/ml solution. Most Al remained in roots, but leaves contained more than did stems of soybeans. The high Al decreased Fe, Cu, and Mn concentrations in shoots of rice and decreased Fe, Cu, and Zn in roots of rice. The high Al resulted in decreased Fe and Zn in leaves of soybeans. No Fe deficiency symptoms were present due to the high Al.  相似文献   

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