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
Phosphorus uptake kinetics were measured on 30‐day‐old wheat using split‐root experiments. Supplying P to only part of the root system resulted in lower plant P concentration and higher Imax(maximum influx) by the roots. The Imax value of wheat roots was much lower than corn (Zea mays L.) and soybeans (Glycine max L.), but the values of Km (the solution P concentration where influx, In is 1/2 Imax) and Cmin (the solution P concentration where influx, In is 1/2 Imax) were greater than those of both corn and soybean crops grown in similar experiments. Phosphorus concentrations in wheat plant's shoots and roots were higher than those for corn and soybean with the same proportions of roots in P solution. Decreasing the proportion of the roots supplied with P had no statistically significant (p = 0.05) effect on shoot dry weight. This differs from the results for corn and soybeans where it decreased significantly as the proportion of the roots exposed to P decreased. These results indicate that the effect of P placement on P uptake and on plant root growth varied among species. 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
Phosphorus concentration in soil solution increased slowly with the first increment of P added to the soil. Subsequent P additions increased the P concentrations in solution exponentially. The maximum P absorption by the soil was 324 μg P/g soil and the constant related to P binding energy was 1.37. In addition, the soil buffering capacity decreased with an increase in the amount of P in the soil solution.
Plant shoot dry weight increased linearly with P increase in the concentration range 0.65 to 6.5 μM P in soil solution. However, beyond this level the response was low. The leaf area rate of increase in the 0.65 to 6.5 μM P solution concentration range was 75 times that in the 6.5 to 84 μM P. The root length: shoot dry weight ratio decreased with increasing P supply in the soil solution. P uptake by the plants increased with increased P concentration in soil solution. At soil solution concentrations above 6.5 μMP the rate of P uptake in the shoot was 20 times less than the rate for concentrations below 6.5 μM P. Of the P taken up by tomato seedlings about 65% was in the leaf, 13% in the stem, 13% in the petiole and 9% in the root. 相似文献
The lower root CEC of Pima S‐5 and Stoneville 825 in non‐toxic conditions could provide an initially greater Al tolerance when roots grow into marginally Al toxic soil. Under sustained, Al toxic conditions, root CEC becomes altered and is more of an indirect indicator of root growth as affected by as yet undetermined Al tolerance mechanism(s).
The steady‐state technique to determine root CEC virtually eliminated the inherent problems of CO. effects on pH and titrating to an end point in a specific period of time in a dynamic system. 相似文献
Sunflower plants were grown in nutrient solution with four levels of salinity (0, 1.5, 3.0 and 4.5 atm), induced by NaCl and four rates of Fe chelate (0, 0.5, 1.0 and 1.5, ppm Fe) as FeEDDHA. The experiment was a completely randomized design with treatment combinations arranged in a factorial manner with three replications.
Dry matter yield, shoot‐root ratio, leaf area, plant height and transpiration decreased as salinity increased, the effect of salinity being depressed by iron applications. Salinity reduced P, K, Ca and Mg uptake by roots as well as that of N, P, K, Ca, Mg by shoots, while Fe applications increased uptake of these elements in roots and shoots. Both salinity and iron applications increased Cl, Na and Fe uptake by roots and shoots, as expected. In most instances salinity reduced uptake of Fe, Mn and Zn by the plants while iron applications improved uptake of these elements.
The sunflower plant used in this experiment was found to be, at least partly, tolerant to salinity and decreased water availability as well as toxicity of ions. Nutritional disorders were the cause of decreased plant growth by increasing salinity of the nutrient solution. The decreased plant growth and mineral uptake, induced by salinity, were partially offset by increased iron levels in the nutrient solution. 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
Abbreviations: Ion exchange resin membrane (RM); nitrogen (N); phosphorus (P); potassium (K), sulfur (S), field capacity (FC) 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
Differences in P uptake rates were determined for six sorghum genotypes at 24, 38, and 52 days of age at three P levels. Larger differences were noted among genotypes in 24‐day‐old plants than for older plants. Uptake rates were 6‐ to 14‐times higher (dependent on genotype) in 24‐day‐old plants than in 52‐day‐old plants. NB9040 which had the highest dry matter yield at each age had the lowest rate of P uptake, and CK60‐Korgi which had the lowest dry matter yield at each age had the highest rate of P uptake.
Only small differences were noted among genotypes for distribution of P within plant parts for younger plants. Older plants showed differences in P distribution, and NB9040 translocated more P from lower to upper leaves, had higher efficiency ratios (dry matter produced/unit P), and had a larger root system than CK60‐Korgi.
The sorghum genotypes that produced more dry matter under low P conditions had lower uptake rates of P and had the ability to distribute P from older to younger developing tissues. When grown in soils, plants that have lower P uptake rates, greater ability to distribute P, and larger root systems may not deplete P from soil solutions as rapidly, could explore more soil, and possibly use P more efficiently than plants that do not possess these traits. 相似文献
The effects of mycorrhizal inoculation on plant nutrient concentrations were determined: mycorrhiza-inoculated plants exhibited a higher zinc (Zn), manganese (Mn), copper (Cu), iron (Fe) nutrients concentration than non-inoculated plants. After two years of field experiments, it is concluded that mycorrhizal inoculation can be used in large arable areas; however, it is also very important to manage the indigenous mycorrhiza of arable land. 相似文献
Cultivars showing the greatest sensitivity to Mn toxicity were ‘Wonder Crop 1’ and ‘Wonder Crop 2'; those showing the greatest tolerance were ‘Green Lord’, ‘Red Kidney’ and ‘Edogawa Black Seeded’.
Leaf Mn concentration of plants grown in sand culture was higher than that for plants grown in solution culture. The lowest leaf Mn concentration at which Mn toxicity symptoms developed, was higher in tolerant than in sensitive cultivars. The Fe/Mn ratio in the leaves at which Mn toxicity symptoms developed, was higher in the sensitive cultivars than in the tolerant ones.
We concluded that Mn tolerance in certain bush bean cultivars is due to a greater ability to tolerate a high level of Mn accumulation in the leaves. 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
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
High K plants were shorter and had a greater root:shoot mass ratio than low K plants. A trend for greater root dry matter production in soil layers below 12 cm under high K conditions was observed. There were no differences in root length between the treatments at any depth. Tissue K content was greater in the high K treatments and this Increase was equivalents offset by decreased tissue Mg concentrations. The taller low K plants had a greater leaf area and a lower specific leaf weight, resulting in part from decreased starch content. Daily evapotranspirational water losses per pot tended to be greater under the low K availability regime. This Information led to the speculation that under low K conditions, the soybean plant may increase K accumulation by promoting transpirational water use, aiding soil K acquisition by mass flow and diffusion. Tissue carbohydrate analyses suggest greater translocation of photosynthate out of the leaf in the low K plants for use in root absorption metabolism, rather than for production of increased root dry matter and/or increased root length. 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
Aluminum decreased the amount of N accumulated and the % of N in the aerial parts of the plants. In the roots the amount of N accumulated also decreased but the % of N increased, in both cultivars. Besides an effect on dry matter yield, Al probably reduces the uptake of N and its translocation to the aerial parts of the plant. Apparently, this impairment on N translocation resulted from Al effects on the root pressure.
Aluminum not only reduced the amount of N translocated but also changed the sap composition. The % of NO3 ‐N decreased while the % of amino acid‐N increased suggesting an Al effect on N uptake and also on protein degradation. Asparagine and glutamine contributed about 80% of the free amino acid fraction; however, their proportions changed in presence of Al. Therefore, Al also interfered with the synthesis and/or interconversion of these amino acids. 相似文献
The results show that the yield for eggplant fruits were strongly reduced by a low Mg level, while the yield of cucumbers seemed to be somewhat reduced by a low Ca supply. Sweet pepper yields were not affected among the cation ratios compared.
Relationships between cation contents in the root environment and cation contents in plant tissues were established. The correlation coefficients for these relationships were very high. The equations calculated for the various cations show remarkable differences. Regression coefficients and intercepts strongly depend on crop and plant part sampled. For Mg, it could be established that Ca strongly affected the uptake of Mg. 相似文献
Abbreviations: N: nitrogen; SOM: soil organic matter; POM: particulate organic matter; SOC: soil organic carbon; SON: soil organic nitrogen; POM-C: particulate organic carbon; POM-N: particulate organic nitrogen; Nan: anaerobic nitrogen; Nhyd: hydrolyzable N; NO3-N: cold nitrate; N205: N determined by spectrometer at 205 nm; N260: N determined by spectrometer at 260 nm; Pe: extractable P; Nup: wheat N uptake; NO3-N: inorganic N in the form of nitrate; FR: fallow rainfalls (March-Seeding rainfall); FLR: flowering rainfalls (October-December rainfall); GFR: grain filling rainfall (November rainfall); CCR: crop growing season rainfall (June-December rainfall); PCA: principal component analysis; PC: principal component; MR: multiple regression 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