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191.
A series of eight experiments was conducted using large pots to (1) find the most effective date, site, concentration of K-solution
and K-salt for foliar K-fertilization of maize plants (Zea mays, L.) grown with sufficient K-supply in soil, (2) explain why maize responded to the K-treatment, and (3) examine the influence
of various levels of N and P supplies on the effectiveness of K-fertilizer via the leaves.
A single spraying on sweet maize and field maize on any day between 50% tasselling date to 10 days after tasselling shortened
maturity date, increased grain yield, stover yield, grain-stover ratio, absorption of N, P, K, Ca and Mg, sweetness of young
grain (of sweet maize), and crude protein content of grain. However spraying on the third day after 50% tasselling was most
effective. The second application later than 7 days after the 50% tasselling date suppressed the effects of spraying on the
most effective date. In application of many repetitive sprayings covering the most effective date, a spraying program with
late spraying could reduce grain yield. KNO3, 2.5% KNO3-solution, and applications on all aerial parts were found to be the most effective. Increases in grain yield for spraying
on all aerial parts, spraying on ear leaf only, spraying on all leaves above ear leaf and applying K to soil were 74%, 51%,
41% and 23%, respectively. The foliar K-fertilization affected maize by stimulating chlorophyll synthesis and not by increasing
leaf area. A balance in N and K supplies was determined to be effective for the K-fertilization. 相似文献
192.
Developing cotyledons of the common bean, Phaseolus vulgaris L., transport within their secretory system (endoplasmic reticulum and Golgi apparatus) the abundant vacuolar proteins, phaseolin and phytohemagglutinin. To identify proteins that may play a role in vacuolar targeting, we treated cotyledon microsomal fractions with a bifunctional crosslinking reagent, dithiobis(succinimidyl propionate), isolated protein complexes with antibodies to phaseolin and phytohemagglutinin, and analysed the polypeptides by sodium dodecylsulfate polyacrylamide gel electrophoresis. This allowed us to identify a protein of Mr=9000 (P-9000) that was crosslinked to both phaseolin and phytohemagglutinin. P-900 is abundantly present in the endoplasmic reticulum. The aminoterminus of P-9000 shows extensive sequence identity with the amino-terminus of PA1 (Mr=11 000), a cysteine-rich albumin whose processing products accumulate in the vacuoles of pea (Pisum sativum L.) cotyledons. Like PA1, P-9000 is synthesized as a pre-proprotein that is posttranslationally processed into smaller polypeptides. The possible functions of P-9000 are discussed.Abbreviations DSP
dithiobis(succinimidyl propionate)
- EDTA
ethylenediaminetetraacetic acid
- ER
endoplasmic reticulum
- kDa
kilodalton
- Mr
relative molecular mass
- PHA
phytohemagglutinin
- SDS
sodium dodecylsulfate
- PAGE
polyacrylamide gel electrophoresis 相似文献
193.
Leaf-specific thionins of barley (Hordeum vulgare L.) have been identified as a novel class of cell-wall proteins toxic to plant-pathogenic fungi and possibly involved in the defence mechanism of plants. The distribution of these polypeptides has been studied in the host-pathogen system of barley and Erisyphe graminis DC.f.sp. hordei Marchal (powdery mildew). Immunogold-labelling of thionins in several barley cultivars indicates that resistance or susceptibility may be attributed to the presence or absence of thionins at the penetration site in walls and papillae of epidermal leaf cells.All of the leaf-specific thionin genes are confined to the distal end of the short arm of chromosome 6 of barley. None of the genes for cultivarspecific resistance to powdery mildew which have previously been mapped on barley chromosomes are found close to this locus. 相似文献
194.
195.
Total polyadenylated RNA from ripening or germinating Ricinus communis L. endosperm was translated in rabbit reticulocyte lysate in the absence or presence of canine pancreatic microsomes. The products were immunoprecipitated using antibodies raised againts Triton X-114-extracted integral membrane proteins of protein bodies or glyoxysomes. While the proteins of proteinbody membranes were found to insert co-translationally into added microsomes, this was not observed in the case of glyoxysomal proteins. This observation was confirmed using antibodies raised against a purified glyoxysome membrane protein, alkaline lipase. These results indicate that different routes exist for the insertion of membrane proteins into the two organelles. In both cases membrane-protein insertion does not appear to be accompanied by proteolytic processing.Abbreviations anti-PB
antiserum to integral protein-body membrane proteins
- anti-G
antiserum to integral glyoxysomal membrane proteins
- anti-L
antiserum to alkaline lipase
- ER
endoplasmic reticulum
- Mr
relative molecular mass
- mRNA
poly(A)-rich messenger RNA
- PAGE
polyacrylamide gel electrophoresis
- poly(A)
polyadenylic acid
- SDS
sodium dodecyl sulphate 相似文献
196.
When pea (Pisum sativum L.) embryos were cultured on low osmotica, with or without added abscisic acid (ABA), there was very little change in the
total mRNA translation products resolved by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE).
The only marked alteration was an increase in production of two low-molecular-weight proteins. The purification and partial
characterisation of these two ABA-responsive seed proteins (ABR17 and ABR18) is described. Both proteins were purified to
homoeneity, as judged by SDS-PAGE, from embryos cultured in the presence of ABA. Antisera were raised against both proteins.
Each serum cross-reacted with the other protein, indicating that the proteins are closely related. Their apparent molecular
masses (Mrs) were estimated to be 17200 (ABR17) and 18100 (ABR18) by SDS-PAGE, and 26000 by gel filtration. Both proteins were heterogeneous
on isoelectric focusing. Neither protein was detected (by immunoblotting or immunoprecipitation of cell-free translation products)
in embryos grown in vivo at early to mid-development stages but both were present in embryos late in development. These proteins
appear to be produced late in seed development but are capable of being induced early in development by culturing embryos
in vitro and are markedly enhanced by ABA. 相似文献
197.
Photoaffinity labeling and partial purification of the putative plant receptor for the fungal wilt-inducing toxin,fusicoccin 总被引:1,自引:0,他引:1
The high-affinity fusicoccin-binding protein (FCBP) was solubilized from plasma-membrane vesicles prepared from leaves of Vicia faba L. by aqueous two-phase partitioning. Conditions for the solubilization of intact FCBP-radioligand complexes were worked out. About 60–70% of the complexes can be solubilized with 50–60 mM nonanoyl-N-methylglucamide in the presence of 1 mg· ml-1 soybean phosphatidylcholine, type IV S, and 20% (v/v) glycerol at pH 5.5. The slow dissociation of the radioligand, 9-nor-fusicoccin-8-alcohol-[3H] from the FCBP at low temperatures permits the purification of FCBP-radioligand complexes at 4–10° C by fast protein liquid chromatography on anion-exchange and gel permeation columns. The FCBP, extracted from plasma membranes with cholate and chromatographed in the presence of this detergent, gave an apparent molecular mass (Mr) of 80±20 kDa on gel permeation columns under the conditions used. By comparison of the elution profiles of the fraction most enriched in FCBP-radioligand complexes with polypeptide patterns obtained on sodium dodecyl sulfate-polyacrylamide gels, a polypeptide with an Mr of approx. 34kDa co-separated with the radioactivity profile. A second, faint band of approx. 31 kDa was sometimes also observed co-electrophoresing. Photoaffinity labeling of plasma-membrane vesicles with the new compound 9-nor-8[(3,5-[3H]-4-azidobenzoy)ethylenediamine]-fusicoccin ([3H]ABE-FC) and subsequent separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis labeled a single band with an Mr of 35±1 kDa. Labeling in this band was strongly reduced when the membranes were incubated with [3H]ABE-FC in the presence of 0.1–1 M fusicoccin. From our data, we conclude (i) that the 34-35-kDa polypeptide represents the FCBP and (ii) that in detergent extracts of plasma membranes this polypeptide is probably present as a di- or trimeric structure.Abbreviations ABE-FC
[(4-azidobenzoyl)-ethylenediamine]-fusicoccin
- ABE-NHS
(4-azidobenzoyl)-N-hydroxysuccinimide ester
- FC
fusicoccin
- FCBP
fusicoccin-binding protein
- FCol
9-norfusicoccin-8-alcohol
- MAB
monoclonal antibody
- Mega-9(10)
nonanoyl(decanoyl)-N-methylglucamide
- Mr
apparent molecular mass
- PMSF
phenylmethyl-sulfonyl fluoride
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- TCA
trichloroacetic acid
- Tris
2-amino-2-(hydroxymethyl)-1,3-propanediol 相似文献
198.
When young wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.) plants were deprived of an external sulphate supply (-S plants), the capacity of their roots to absorb sulphate, but not phosphate or potassium, increased rapidly (derepression) so that after 3–5 d it was more than tenfold that of sulphate-sufficient plants (+S plants). This increased capacity was lost rapidly (repression) over a 24-h period when the sulphate supply was restored. There was little effect on the uptake of L-methionine during de-repression of the sulphate-transport system, but S input from methionine during a 24-h pretreatment repressed sulphate influx in both+S and-S plants.Sulphate influx of both+S and-S plants was inhibited by pretreating roots for 1 h with 4,4-diisothiocyanatostilbene-2,2-disulphonic acid (DIDS) at concentrations > 0.1 mol · m-3. This inhibition was substantially reversed by washing for 1 h in DIDS-free medium before measuring influx. Longer-term pretreatment of roots with 0.1 mol·m-3 DIDS delayed de-repression of the sulphatetransport system in-S plants but had no influence on+S plants in 3 d.The sulphydryl-binding reagent, n-ethylmaleimide, was a very potent inhibitor of sulphate influx in-S roots, but was much less inhibitory in +S roots. Its effects were essentially irreversible and were proportionately the same at all sulphate concentrations within the range of operation of the high-affinity sulphate-transport system. Inhibition of influx was 85–96% by 300 s pretreatment by 0.3 mol·m-3
n-ethylmaleimide. No protection of the transport system could be observed by including up to 50 mol·m-3 sulphate in the n-ethylmaleimide pre-treatment solution. A similar differential sensitivity of-S and+S plants was seen with p-chloromercuriphenyl sulphonic acid.The arginyl-binding reagent, phenylglyoxal, supplied to roots at 0.25 or 1 mol·m-3 strongly inhibited influx in-S wheat plants (by up to 95%) but reduced influx by only one-half in+S plants. The inhibition of sulphate influx in-S plants was much greater than that of phosphate influx and could not be prevented by relatively high (100 mol·m-3 sulphate concentrations accompanying phenylglyoxal treatment. Effects of phenylglyoxal pretreatment were unchanged for at least 30 min after its removal from the solution but thereafter the capacity for sulphate influx was restored. The amount of new carrier appearing in-S roots was far greater than in+S roots over a 24-h period.The results indicate that, in the de-repressed state, the sulphate transporter is more sensitive to reagents binding sulphydryl and arginyl residues. This suggests a number of strategies for identifying the proteins involved in sulphate transport.Abbreviations DIDS
4,4-diisothiocyanatostilbene-2,2-disulphonic acid
- NEM
n-ethylmaleimide
- PCMBS
p-chloromercuriphenyl sulphonic acid 相似文献
199.
Diurnal oscillations of steady-state mRNA levels encoding the chlorophyll a/b-binding proteins were monitored inLycopersicon esculentum, Glycine max, Phaseolus vulgaris, P. aureus, P. coccineus, Pisum sativum, Sinapis alba, Hordeum vulgare,
Triticum aestivum andZea mays. In these plant speciescab mRNA accumulation increases and decreases periodically indicating i) that the expression of the genes for chlorophyll a/b-binding
proteins (cab genes) is controlled by a circadian rhythm, and ii) that the rhythm is widely distributed among monocotyledonous and dicotyledonous
plant species. A detailed characterization of the pattern ofcab mRNA expression in tomato leaves shows that the amplitude of the oscillation is dependent on i) the developmental stage of
the leaves, ii) the circadian phase and duration of light and iii) the circadian phase and duration of darkness. In addition
to the chlorophyll a/b-binding proteins, genes coding for other cellular functions were examined for cyclic variations of
their mRNA levels. The analysis includes genes involved in i) carbon metabolism (e.g. phosphoenolpyruvate carboxylase, pyruvate
orthophosphate dikinase, alpha amylase, fructose-1,6-bisphosphate aldolase, triosephosphate isomerase), ii) photosynthesis
(large and small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase, QB-binding protein, reaction-center protein of photosystem I) and iii) other physiological or morphological reactions (e.g.
ubiquitin, actin). However, no periodic fluctuation pattern was detected for the mRNA levels of these genes in tomato and
maize leaves. 相似文献
200.
Two proteolytic enzymes, a cysteine proteinase and a carboxypeptidase, responsible for breakdown of the main storage protein, 13S globulin, were purified from buckwheat seedlings (Fagopyrum esculentum Moench) by (NH4)2SO4 fractionation, gel-filtration on Sephadex G-150, ionexchange chromatography on DEAE-Toyopearl 650 M and chromatofocusing. The cysteine proteinase was purified 74-fold. It has a pH optimum of 5.5, a pI of 4.5 and an apparent molecular mass (Mr) of 71000. The carboxypeptidase was purified 128-fold. It has a pH optimum of 5.3, a pI of 5.8 and a Mr of 78500. Cysteine proteinase hydrolyzed the modified 13S globulin only if the reaction products were eliminated from the incubation mixture by dialysis. Storage protein degradation by the proteinase increased in the presence of carboxypeptidase. We suggest that the two enzymes complete the digestion of 13S globulin after its preliminary hydrolysis by the earlier described enzyme, metalloproteinase, present in dry buckwheat seeds.Abbreviations BSA
bovine serum albumin
- DEAE
diethylaminoethyl
- Mr
apparent molecular mass
- PAGE
polyacrylamide gel electrophoresis
- SDS
sodium dodecyl sulfate 相似文献