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91.
Abscisic acid and water transport in sunflowers 总被引:5,自引:0,他引:5
The role of abscisic acid (ABA) in the transport of water and ions from the root to the shoot of sunflower plants (Helianthus annuus) was investigated by application of ABA either to the root medium or to the apical bud. The exudation at the hypocotyl stump of decapitated seedlings was measured with and without hydrostatic pressure (0–0.3 MPa) applied to the root. All ABA concentrations tested (10-10–10-4 mol·l-1) promoted exudation. Maximal amounts of exudate (200% of control) were obtained with ABA at 10-6·mol·l-1 and an externally applied pressure of 0.1 MPa. The effect was rapid and long-lasting, and involved promotion of ion release to the xylem (during the first hours) as well as an increase in hydraulic conductivity. Abscisic acid applied to the apical bud had effects similar to those of the rootapplied hormone. Increased rates of exudation were also obtained after osmotic stress was applied to the root; this treatment increased the endogenous level of ABA in the root as well as in the shoot. Water potentials of the hypocotyls of intact plants increased when the roots were treated with ABA at 5°C, whereas stomatal resistances were lowered. The results are consistent with the view that ABA controls the water status of the plant not only by regulating stomatal transpiration, but also by regulating the hydraulic conductivity of the root.Abbreviations and symbols ABA
abscisic acid
- Tv
volume flow
- Lp
hydraulic conductivity
- PEG
polyethyleneglycol
-
water potential
-
osmotic potential
-
osmotic value
- P
hydrostatic pressure 相似文献
92.
93.
94.
Alia Islam Obaid Ullah Beg Bengt Persson Zafar H. Zaidi Hans Jörnvall 《The protein journal》1988,7(5):561-569
The structure of the hernoglobin α-chain of Rose-ringed Parakeet was determined by sequence degradations of the intact subunit, the CNBr fragments, and peptides obtained by digestion with staphylococcal Glu-specific protease and trypsin. Using this analysis, the complete α-chain structure of 21 avian species is known, permitting comparisons of the protein structure and of avian relationships. The structure exhibits differences from previously established avian α-chains at a total of 61 positions, five of which have residues unique to those of the parakeet (Ser-12, Gly-65, Ser-67, Ala-121, and Leu-134). The analysis defines hemoglobin variation within an additional avian order (Psittaciformes), demonstrates distant patterns for evaluation of relationships within other avian orders, and lends support to taxonomic conclusions from molecular data. 相似文献
95.
96.
Koji Adachi Paul Belser Hans Bender Derui Li Ulrich Rodeck Etty N. Benveniste David Woo Wolff H. Schmiegel Dorothee Herlyn 《Cancer immunology, immunotherapy : CII》1992,34(6):370-376
Summary Recombinant tumor necrosis factor (rTNF; optimal dose 1000 U/ml) significantly increased the density of epidermal growth factor receptor (EGF-R) in three of four glioma cell lines in culture as determined by binding analysis of anti-EGF-R monoclonal antibody (mAb) 425. Since enhancement of EGF-R expression by rTNF- was inhibited when cells were treated with the protein synthesis inhibitor cycloheximide, the effects of rTNF may be protein-synthesis-dependent. The dose of rTNF that was optimal for up-regulation of EGF-R on glioma cells did not inhibit the growth of these cells.125I-labeled mAb 425 lysed glioma cells in culture following its internalization into the cells. After glioma cells had been treated with rTNF, the growth-inhibitory effects of the mAb were significantly enhanced, probably a reflection of the increase in EGF-R density on the tumor cell surfaces. The rTNF effects were specific to the EGF-R and did not affect unrelated glioma-associated antigens. In our previous clinical trials,125I-labeled mAb 425 showed immunotherapeutic effects in glioma patients. The present study provides the basis for considerations of combined immunotherapy of glioma patients with125I-labeled mAb 425 and rTNF. 相似文献
97.
Sauer Arne E.; Karg Gerhard; Koch Uwe T.; De Kramer Jacobus J.; Milli Roland 《Chemical senses》1992,17(5):543-553
A robust and portable apparatus for the measurement of pheromoneconcentrations under field conditions has been developed. Ituses the insect antenna (Lobesia botrana Hb.) itself as a sensitiveand specific pheromone detector. Shock-proof contact with theelectrodes is maintained by fixing the antenna in a specially-shapedplexiglass holder mounted within a glass tube. This allows measurementsto be made while moving the apparatus. Continuous airflow throughthe tube is generated by a suction pump and the incoming aircan be purified by passage through a charcoal filter. This allowsto readjust the offset and to calibrate the instrument by theapplication of pheromone pulses of known concentrations. Removalof the filter allows the direct access of ambient air over theantenna which responds by generating an electro-antennogram(EAG) as a measure of the pheromone concentration. Using the calibration curve, relative pheromone concentrationsin ambient air in a vineyard can be determined. Sample measurementsfrom areas treated with artificial pheromone for pest controlare presented. 相似文献
98.
Regeneration of transgenic plants of Prunus armeniaca containing the coat protein gene of Plum Pox Virus 总被引:1,自引:0,他引:1
Margit Laimer da Câmara Machado Artur da Câmara Machado Veronika Hanzer Hans Weiss Ferdinand Regner Herta Steinkellner Diethard Mattanovich Regina Plail Elisabeth Knapp Birgit Kalthoff Hermann Katinger 《Plant cell reports》1992,11(1):25-29
Summary A system was developed which allows the transfer of foreign genes into apricot cultivars. We report the transformation and regeneration of Prunus armeniaca plants with Agrobacterium tumefaciens strain LBA 4404 containing various binary plasmids, pBinGUSint, carrying the marker gene ß-glucuronidase (GUS) and pBinPPVm, carrying the coat protein gene of Plum Pox Virus (PPV). The marker gene GUS was used for optical evaluation of the efficiency of the transformation system. The coat protein gene of PPV was used to introduce coat protein mediated resistance against one of the most important pathogens of stone fruit trees in Europe and the whole Mediterranean area. This is the first report of the successful integration of a viral coat protein gene into a fruit tree species, opening a new perspective on the control of the disease.Abbreviations GUS
ß-glucuronidase
- PPV
Plum Pox Virus
- BA
6-benzylaminopurine
- NPTII
neomycin phosphotransferase II
- CP
coat protein
- CaMV
Cauliflower Mosaic Virus
- P35S 35S
promoter
- MS
Murashige and Skoog
- PCR
polymerase chain reaction
- P/C/I
phenol/chloroform/isoamylalcohol
- RNase
ribonuclease
- dNTP
deoxyribonucleosidetriphosphate
- DMSO
dimethyl sulfoxide 相似文献
99.
Ruth G. Troetschler Steven J. Kramer 《Archives of insect biochemistry and physiology》1992,20(1):35-47
The mode of action of a diuretic hormone from pharate adult Manduca Sexta heads, which triggers fluid loss in M. sexta larvae and Pieris rapae adults, was studied. In vivo, Mas-DH (M. sexta diuretic hormone) decreased fluid absorption from larval recta, and increased levels of the second messenger cAMP in recta and Malpighian tubules (Mt) from larvae, and in fat body of larvae and adult M. sexta. In vitro, Mas-DH triggered minor changes in fluid loss from adult Mt, but did not affect levels of cAMP in Mt from larvae, pharate adults, or adults, though it elevated cAMP levels in fat body of these stages. © 1992 Wiley-Liss, Inc. 相似文献
100.