8 resultados para Leaf fertilization

em Brock University, Canada


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Soybean (Glycine ~ (L.) Merr. cv. Harosoy 63) plants inoculated with Rhizobium japonicum were grown in vermiculite in the presence or absence of nitrate fertilization for up to 6 weeks after planting. Overall growth of nodulated plants was enhanced in the presence of nitrate fertilization, while the extent of nodule development was reduced. Although the number of nodules was not affected by nitrate fertilization when plants were grown at a light intensity limiting for photosynthesis, at light intensities approaching or exceeding the light saturation point for photosynthesis, nitrate fertilization resulted in at least a 30% reduction in nodule numbers. The mature, first trifoliate leaf of 21 day old plants was allowed to photoassimi1ate 14C02. One hour after·· the initial exposure to 14C02, the , plants were harvested and the 14C radioactivity was determined in the 80% ethanol-soluble fraction: in. o:rider to assess· "the extent of photoassimilate export and the pattern of distribution of exported 14C. The magnitude of 14C export was not affected by the presence of nitrate fertilization. However, there was a significant effect on the distribution pattern, particularly with regard to the partitioning of 14C-photosynthate between the nodules and the root tissue. In the presence of nitrate fertilization, less than 6% of the exported 14C photosynthate was recovered from the nodules, with much larger amounts (approximately 37%) being recovered from the root tissue. In the absence of nitrate fertilization, recovery of exported 14C-photosynthate from the nodules (19 to 27%) was approximately equal to that from the root tissue (24 to 33%). By initiating- or terminating the applications of nitrate at 14 days of age, it was determined that the period from day 14 to day 21 after planting was particularly significant for the development of nodules initiated earlier. Addition of nitrate fertilization at this time inhibited further nodule development while stimulating plant growth, whereas removal of nitrate fertilization stimulated nodule development. The results obtained are consistent with the hypothesis that nodule development is inhibited by nitrate fertilization through a reduction in the availability of photosynthate to the nodules.

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The hypothesis that rapid y-aminobutyric acid (GABA) accumulation is a plant defense against phytophagous insects was investigated. Simulation of mechanical damage resulting from phytophagous insect activity increased soybean (Glycine max L.) leaf GABA 10- to 25-fold within 1 to 4 min. Pulverizing leaf tissue resulted in a value of 2. 15 (±O. 11 SE) ~mol GABA per gram fresh weight. Increasing the GABA levels in a synthetic diet from 1.6 to 2.6 Jlffiol GABA per gram fresh weight reduced the growth rates, developmental rates, total biomass (50% reduction), and survival rates (30% reduction) of cultured Oblique banded leaf-roller (OBLR) (Choristonellra rosacealla Harris) larvae. In field experiments OBLR larvae were found predominantly on young terminal leaves which have a reduced capacity to produce GABA in response to mechanical damage. Glutamate decarboxylase (GAD) is a cytosolic enzyme which catalyses the decarboxylation of L-Glu to GABA. GAD is a calmodulin binding enzyme whose activity is stimulated dramatically by increased cytosolic H+ or Ca2 + ion concentrations. Phytophagous insect activity will disrupt the cellular compartmentation of H+ and Ca2 +, activate GAD and subsequent GABA accumulation. In animals GABA is a major inhibitory neurotransmitter. The possible mechanisms resulting in GABA inhibited growth and development of insects are discussed.

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Ontario Editorial Bureau (O.E.B.)

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The text reads as follows: nomen Domini invocabo. V. Date magnitudinem Deo nostro: Deus, vera opera eius, et omnes viae eius indicia. V. Deus fidelis, in quo….. Translated: I will invoke the name of the Lord. V. Give ye magnificence to our God: The works of God are perfect, and all his ways are judgments. V. Let my doctrine gather as the rain…..

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The text reads as follows: Narrator: Passio domini nostri iesu christi secundum matheum. In illo tempore dixit iusus discipulis suis. Christ: Scritis quia post biduum pascha fiet, et filius hominis tradetur ut crucifigatur. Narrator: Tumc congregati sunt principes sacerdotum et seniores populi, in atrium principis… Translated: Narrator: The Passion of Our Lord Jesus Christ according to Matthew. “And it came to pass when Jesus had finished all of these words that he said to his disciples: Christ: You know that after two days the Passover will be here; and the Son of Man will be delivered up to be crucified. Narrator: Then the chief priests and the elders of the people gathered together in the court of the high priest…

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Envelope containing a four leaf clover “for luck” and little Margaret’s hair (9 mos. old), Sept. 3, 1937.

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Gold leaf that belonged to great grandmother French. This is enclosed in an envelope which has Jas. Carruthers and Co. Grain Exporters, New York as a return address, n.d.