Materials and methods: Rootstocks B9 and M9 with a size suitable for grafting (6-10 mm stem diameter, termed rootstocks), and smaller sized rootstocks (<5 mm stem diameter, termed transplants) of B9, M9, M26, MM106 and Antonovka were inoculated with N. ditissima at different times, either with contaminated map pins or with spore suspensions. In addition, the rootstocks were either defeathered (side shoots removed), topped (top shoot headed) or both, to create wounds that would normally occur during propagation, while wounds on transplants were made by removing leaves.
Results and discussion: One month after inoculation, slightly sunken canker lesions had developed around the inoculation points of the map pins or wounds. No lesions developed on the non-inoculated controls. Map pin inoculation resulted in 30% to 89% infection and spore suspension sprayed on wounds from 5% to 45% infection. When the cankered areas were split open, brown lesions with necrotic tissue due to infection by N. ditissima appeared. The transplants of M9, M26 and MM106 inoculated with contaminated map pins in 2014 developed necrosis on 40% to 67% of the plants, but there were no differences in the incidence or severity among the different types. On the transplants of B9, Antonovka and M9 inoculated in 2015, there was more necrosis on B9 (42%) than on Antonovka (11%) and more sporulating lesions on B9 (29%) than on M9 (9%) or on Antonovka (4%).
Conclusion: It can be concluded that rootstocks used for apple trees may become infected by N. ditissima, and wounds should thus be protected during propagation. 相似文献
Materials and methods: The paper presented a comprehensive account of Striga screening and controlling techniques and highlighted the potential of integrating partial resistance with FOS to boost maize production and productivity in SSA.
Results: Striga infestation is a major constraint to maize production and productivity in Sub-Saharan Africa (SSA). A lack of Striga-resistant maize varieties and the limited adoption of other control methods hinder effective and integrated control of the parasitic weed in maize and related cereal crops globally. Genetic resistance of maize should be complemented with the use of Fusarium oxysporum f.sp. strigea (FOS), a biocontrol agent known to suppress Striga.
Conclusions: A combined use of genetic resistance and FOS has remained largely unutilized in controlling Striga in Africa. A combination of conventional and molecular Striga-resistance breeding tools as well as the use of FOS are promising methods to effectively control Striga in SSA. 相似文献
Materials and methods: The number of snails on citrus trees was monitored and counted 10 days after the application of the treatments, and at an interval of 6–8 days up to harvest time.
Results: In the first study, the mineral oil and repellent paint treatments reduced a number of snails best. In the second study, using metaldehyde and mineral oil barrier, again the mineral oil barrier reduced snails best. The cost of each treatment during one season per hectare was calculated at 55, 153, 124 and 120?$/ha for mineral oil, iron phosphate, snail-repellent paint and metaldehyde, respectively.
Conclusions: Mineral oil is an effective alternative for chemical compounds for reducing access by H. candeharica to citrus trees. 相似文献
Materials and methods: Endophytic bacteria were isolated from root, stem, and leaf of ginseng from different sites and genotype in China and Korea, screened based on their beneficial properties as PGPB. Nine bacterial isolates were selected according to their plant growth properties including soluble phosphate and potassium, ammonia, auxin and siderophore producing, ACC deaminase, and antagonistic pathogen as well. Changes in ginseng after PGPB inoculation were evaluated with respect to the non-inoculated control.
Results and Conclusions: The PGPB isolates were identified as genera Bacillus, Lysinibacillus, Rhizobium, Stenotrophomonas, Erwinia, Ochrobactrum, Enterobacter and Pantoea based on 16S rRNA sequences. Inoculation of G209 and G119 increased not only plant height, root length, fresh weight, and dry weight, but also root activity and the amount of ginsenosides significantly. In particular, using the Illumina Miseq platform, the native bacterial community of rhizospheric soil maintained high community diversity and increased abundance of specific bacteria. Therefore, they may be play a crucial role in sustainable ginseng cultivating in farmland. 相似文献
Materials and methods: Four treatments (root drench, root damaging and drench, root drench with matrine, and flower spray) were applied to inoculate alfalfa with two fluorescent-tagged rhizobia, Ensifer meliloti LZgn5f (gn5f) and Ensifer meliloti 12531f (12531f), at three different growth stages; bud, flower and pod stages. The migration and colonisation dynamics of the two fluorescent tagged rhizobia strains were monitored using UV lamp detection and a stereo fluorescence microscopy.
Results: The results showed that both rhizobia strains mainly colonised the roots and could migrate to aerial tissues. In aerial tissues, when alfalfa plants were inoculated during the bud stage, both rhizobia strains mainly colonised the leaves and stems; during the flower stage, a spray inoculation treatment resulted in more 12531f colonising reproductive tissues, while during the pod stage, more rhizobial strains gn5f colonised seeds using the root drench with matrine treatment.
Conclusions: These results indicate that endophytic rhizobia are natural inhabitants of internal regions of roots, stems, leaves and that the endophytes may arise from reproductive tissues, such as seeds. Understanding the population dynamics of endophytic rhizobia in alfalfa would considerably improve the survival of target rhizobia during seed transfer. Combining target endogenous rhizobial species with good alfalfa seed varieties may lead to the development of a novel breeding method. 相似文献
Materials and methods: Tomato plants were subjected to three organic nutrient solutions, which consisted of different mixtures of several OMRI (Organic Materials Review Institute) certified nitrogen fertilizers of industrially processed residues: Treatment I: solid and soluble liquid fertilizers of animal raw materials, natural potassium sulphate-non-synthetic, and calcium chloride; Treatment II: solid and soluble liquid fertilizers of animal raw materials, by-product of marine raw material (soluble liquid), natural potassium sulphate-non-synthetic, and calcium chloride; and Treatment III: solid fertilizers of animal raw materials, natural potassium sulphate-non-synthetic, and calcium chloride to 100% [0-30 days after transplanting (DAT)], 125% [31-80 DAT], and 150% [>81 DAT]. The Steiner solution (SS) was used as a control (Treatment IV).
Results: Yield did not differ between organic and conventional treatments, ranging from 3.04 to 3.35 kg m-2 while fresh weight in organic treatments was 3.14 compared to 3.2 kg m-2 in plants fed with the SS. No significant differences in plant height or fruit quality were found. The application of organic fertilizers positively affected the total hydrolysable and condensed polyphenols of tomato fruits compared to the control. Twelve phenolic compounds were identified, highlighting 3-Caffeoylquinic acid, salvianolic acid and 5,6-Dihydroxy-7,8,3’,4’-tetramethoxyflavone (Treatment I) and Medioresinol (Lignan) (Treatment II).
Conclusions: The results indicated that organic fertilization through animal-based fertilizer application is a feasible alternative for grape tomato production under greenhouse conditions. 相似文献
AMF colonization was evaluated by visual observation of AMF in fine roots of eight herbaceous plants. The level of mycorrhizal colonization varied between plants. Astragalus corrugatus and Hippocrepis areolata showed the highest mycorrhizal performance. The relative spore number was significantly different across rhizosphere soils. Statistical analysis showed a clearly positive correlation between the number of spores and plant-mycorrhizal intensity.
For microbiological parameters, our results showed that mycorrhizal plants improved significantly the various microbiological parameters. Rhizosphere soils of Astragalus corrugatus and Hippocrepis areolata presented the necessary microbial densities and microorganisms more stable compared to unplanted soil. This study allowed obtaining a new result that challenges us about the need for efficient management of natural resources in the objective of nature conservation. 相似文献
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Information on the size of nutrient flux values and their change with increasing plant age can be used to determine the nutrient levels needed in the soil to supply nutrients rapidly enough to the root surface to minimize deficiencies. The objective of this research was to determine the relation between plant age and P absorption properties and root growth characteristics of wheat (Triticum vulgare L.) cv. Era.
Wheat was grown for periods up to 42 days in solution culture in a controlled climate chamber. Sequential harvests were made and P uptake and root morphology were measured. Shoot growth was exponential with time to 32 days and linear thereafter. Root dry weights increased linearly with time at a slower rate than shoot dry weights. Root length increased logarithmically with time (r2 = 0.95; log y = 0.069x + 1.85).
With increasing plant age there was a reduction in average P uptake rate by wheat roots. 相似文献
Sulfur treatments consisted of four levels (0, 1, 2.5, and 25 mg S/L) of added S. The experimental design was a randomized complete block, with three replications. Seeds were inoculated with commercial inoculum, planted in plastic containers of acid‐washed sand, and irrigated with nutrient solution for one minute, at 2 h intervals.
Sulfur application increased the yield of all treatments. The results demonstrated that the addition of 2.5 mg S/L to the nutrient solution, besides providing the highest total dry matter yield (12 g/72 plants), showed the highest percent yield increase (19%), acetylene reduction rate (0.426 umole ethylene/mg nodule dry wt/h), total N content (306 mg/72 plants), percent recovery of S (3.8%), and percent increase in N due to dinitrogen fixation (32%).
N:S ratios obtained were different for shoots and roots, with S application decreasing the N:S ratios. The N:S ratios of 16:1 (shoots), and 9:1 (roots) obtained in the 2.5 mg S/L treatment were found to be adequate for normal growth and development.
These data indicated that the 2.5 mg S/L treatment (2.7 mg total S/L) was optimal for alfalfa seedling development. 相似文献
Poppies were highly sensitive to manganese toxicity in solution culture and reductions in shoot yield occurred at lower manganese levels in solution and at lower shoot manganese concentrations than that for the following sensitive species, ranked in order of increasing tolerance : brussels sprout, barley, green beans, lucerne and grean pea. In contrast lupins, oats and sugar beet were relatively tolerant producing about 80% or more of maximum shoot yield at the highest solution manganese level (800 μM Mn).
In this study the sensitivity of poppy, and brussels sprout, to manganese excess was attributed to their low shoot manganese “toxicity threshold values”; and their capacity to partition a high proportion of total plant manganese and dry matter to the shoot at solution manganese levels ≥ 100 μM.
The application of these results to field grown poppy is discussed in relation to interactions between manganese and other elements which modify plant tolerance to manganese excess. 相似文献
Materials and methods: The growth of roots and root hairs as well as uptake of macro- and micronutrients of six spring wheat varieties was compared in solution culture under P stress and P abundance and in a low fertility soil.
Results and conclusions: Root length and surface area under P stress were significantly positively correlated with that in the low fertility soil, while no such correlation was apparent for root hair length and density. In absolute terms, the root length, surface area, root hair length and density of spring wheat varieties were substantially higher in soil than in solution culture, while the concentration and uptake of macro- and micronutrients in soil differed from solution culture in a complex way. The early uptake of macro- and micronutrients was intimately associated with root length and surface area as well as root hair length and density in soil but not in solution culture. Therefore, root length rather than root hair traits in low-P solution may be used to screen early root growth vigor in soil and thereby high nutrient uptake of wheat in low fertility soil. 相似文献
P and Mn deficiencies do not alter the total flavonoid level. Nevertheless, these deficiencies lead to different contributions of each flavonoid group (flavonols, flavones and flavanones) to the whole content.
B deficiency produces a very significant increase in total flavonoid content. Compounds that contribute the most to this accumulation are flavones. 相似文献
Increased Kg concentrations were observed with increased solution Mg. Increased solution K was in all cases associated with lower concentrations of Mg. Under conditions of low solution K (0.125 mM) and adequate Mg (0.25 mM), Mg accumulation exceeded 1.0%. Increased solution N was associated with decreased Mg concentrations. Both the linear and quadratic components of Mg solution concentration contributed significantly to increased tissue Mg. Hawever, the linear component of K solution concentration was sufficient to account for decreased tissue Mg. The reduction of tissue Mg to solution K was greater at higher concentrations of K.
Potassium accumulation significantly increased with increased solution K. Increased solution Mg was associated with lower tissue K in which the greatest reduction in K accumulation occurred with the first Mg addition.
Calcium accumulation decreased with increased solution K. Higher solution Mg was associated with lower tissue Ca levels while higher levels of N were associated with increased tissue Ca. Sodium accumulation was significantly reduced by increased K concentrations but neither Mg nor N was effective in consistently altering tissue Na concentrations.
From these experiments it is evident that Kenhy tall fescue has the absorptive capability for high levels of Mg under conditions of low levels of solution K. However, even small increments of solution K were shown to be capable of substantially reducing the Mg content, Thus, the selection of forage grasses for Mg absorptive capability must be conducted under conditions of high solution K, if large improvements on present forage materials are to be obtained. In addition, the inverse relationship between Mg and K present in Kenhy seedlings confirms the need to consider K fertilization recommendations in attempting to increase forage Mg durirg the grass tetany period. 相似文献
Toxicity symptoms, induced by low levels of Mn (0.1 ppm and above), included: small brown necrotic spots and veinal necrosis on primary leaves; necrosis on primary leaf petioles; interveinal chlorosis, with or without brown necrotic spots, on trifoliate leaves; and brown necrotic spots on stipules. Manganese toxicity symptoms were alleviated or prevented by increasing Fe concentration in the nutrient solution.
Manganese concentration in the leaves increased with increasing Mn and decreased with increasing Fe concentration in the nutrient solution, Iron concentration in the roots increased with increasing Fe concentration in the nutrient solution; however, Fe concentration in the leaves was not significantly affected by increasing Mn concentration in the solution culture. Manganese toxicity symptoms developed when Mn concentration in the leaves reached about 120 ppm.
A decrease in the Fe/Mn ratio in the nutrient solution resulted in a proportionate decrease in that of the leaves. Manganese toxicity symptoms occurred when the Fe/Mn ratio in the solution was 10.0 and below, or when the ratio in the leaves was less than 1.5. The ratio of Fe/Mn in the solution required for optimum growth of ‘Wonder Crop No. 2’ bean, without Mn toxicity symptoms, was in the range of 20.0 to 25.0.
Results indicate that the chlorosis on bush bean leaves induced by excessive Mn in the nutrient solution was due to excessive accumulation of Mn and not to Fe deficiency. 相似文献
In the first experiment, sunflower was grown in nutrient solutions containing four levels of P(1.5, 2.5, 3.5 and 4.5 mM/l) and three levels of Fe(0.25, 0.75, and 1.5 ppm) as FeCl3 or FeEDDHA. In the second experiment (following the first experiment), the treatments were three P levels (0.75, 1.50 and 3.00 mM/l), three Fe levels (0.25, 0.75 and 1.5 ppm) as FeEDDHA and three Zn levels (0.1, 0.2 and 0.4 ppm).
The plants receiving Fe‐chelate, except for 0.25 ppm Fe, showed no symptoms of iron chlorosis. With inorganic Fe treatments, iron chlorosis appeared after 7–10 days depending on P level, but except for 0.25 ppm Fe which remained chlorotic, plants recovered completely within 3–4 days thereafter due to pH regulating mechanism of sunflower under iron stress condition. With both sources of Fe, chlorosis was associated with high P:Fe ratio.
Increased P and Fe levels in nutrient solution resulted in general increases in the dry weights of roots and shoots. The Fe concentration of shoots, except in few instances, was not affected by P levels, indicating that the sunflower cultivar used in this experiment could utilize inorganic Fe as well as Fe‐chelate under our experimental conditions.
Increasing P levels caused significant increases in Mn content of the shoots as 0.25 and 0.75 ppm inorganic Fe3+. Increased Fe levels increased shoot Mn content with inorganic Fe and decreased it with Fe‐chelate. The effects of P, Fe and Zn on sunflower indicated an antagonistic effect of Zn on 1.5 ppm Fe for all P levels. Increased Zn levels in nutrient solution generally increased Zn content of the shoots without having any marked effect on their Mn content. 相似文献
One decade after mechanical crushing of shrubs for grassland restoration, soil amino sugar nitrogen (N) values and patterns for resprouted honey mesquite and undisturbed shrubs did not differ from one another according to a repeated measures analysis of variance. However, the concentrations in samples of the surficial 30-cm of soil around undisturbed and resprouted shrubs combined differed statistically at 161 parts per million (ppm) at trunk, 100 ppm midway between trunk and dripline, 78 ppm at the dripline, and 46 ppm beyond the dripline.
The results indicate that soil N fertility remained stable, but with decreasing levels at regular, radial sample points extending from the trunk to beyond the dripline, around mesquite shrubs that resprouted 10 years after mechanical crushing of tops for grassland restoration. 相似文献
At pH 4 in the presence of plant roots, reduction of iron(III) to iron(II) occurred as indicated by Fe2+ BPDS formation. BPDS in a 3:1 ratio to iron(III) suppressed iron uptake by about 70%. The reduction was observed to be located in the endodermis of young roots and exodermis of older roots.
A capacity to oxidize iron(II) at the root surface was also observed under local anaerobic and relatively high pH conditions.
The significance of these two counteracting processes in affecting the oxidation state of iron at the root surface is discussed. 相似文献
Fifteen strains, representing five species, were grown in greenhouse pots of an acid, Al‐toxic Tatum soil limed to pH 4.8 and 5.8. Strains differed significantly in tolerance to the acid soil. Relative yields (pH 4.8/pH 5.8%) ranged from 50.1 to 6.3% for tops and from 54.5 to 5.7% for roots. Four strains of A. tricolor L. (vegetable type) were significantly more tolerant than six strains of A. cruentus L. (seed and vegetable type). Strains of A. hypochondriacus L. and A. caudatus L. studied were intermediate in tolerance.
Twelve strains, representing four species, were grown on an acid, Mn‐toxic Zanesville soil at pH 4.6 and 6.3. Strains also differed significantly in tolerance to this acid soil; however, overall growth was better and strain differences were smaller than on Al‐toxic Tatum soil at pH 4.8. On Zanesville soil the relative top yields (pH 4.6/pH 6.3%) ranged from 74.1 to 18.6%. The most tolerant group included three strains of A. tricolor and one strain of A. hypochondriacus, but four strains of A. cruentus were also fairly tolerant. The sensitive end of the scale included one strain of A. cruentus and two strains of A. hypochondriacus.
In general, strains that were most tolerant to the Al‐toxic Tatum soil were also among the most tolerant to the Mn‐toxic Zanesville soil. Likewise, those most sensitive to the high Al soil were most sensitive to the high Mn soil. But some strains that were sensitive to excess Al in Tatum soil were fairly tolerant to high Mn in Zanesville soil.
Results suggest that superior strains of Amaranthus can be selected or developed for use on acid soils. 相似文献
Inoculation of plants together with nitrogen or sulphur application produces an increase in the concentration of total nitrogen and a decrease in the accumulation of nitrate‐nitrogen and sulphate‐sulphur in shoot, fruit and root. Leaf area increased more with nitrogen than with sulphur application while the highest amounts of fruit dry matter were obtained with sulphur application.
N: S ratios obtained were different according to the part of the plant tested. Sulphur fertilization decreased the N: S ratios in shoot, fruit and root. The data obtained indicate that and adequate N: S ratio can insure maximum production of yield. 相似文献