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91.
92.
Systematic studies were undertaken on the Caloglossa continua ( Okamura) King et Puttock complex from Japan, Singapore, and Australia, based on morphology and reproductive compatibility. Specimens from Japan had two to six cell rows derived from a nodal axial cell, at the margin opposite the branch, whereas those from Australia possessed only a single cell row. Specimens from Singapore formed one to four cell rows per nodal axial cell and always contained at least one single cell row on any one thallus. These differences were maintained in cultured materials over a range of temperatures or salinities. Type material of C. continua had the same morphology as the Japanese specimens in this study. Carpospores discharged from the Japanese isolate germinated at 10°C, whereas those from Singapore and Australia died at this temperature. In hybridization experiments, the Japanese entity was completely nonfertile with both the Singaporean and Australian isolates. Many pseudocystocarps were produced in the crossing between the male from Australia and the female from Singapore, although the reciprocal combination did not produce any such structures. On the basis of the discontinuous morphology coupled with the complete reproductive isolation, the entities from Singapore and Australia are described here as C. monosticha sp. nov. The entities with multiple cell rows likely expanded their geographic range from tropical regions, where the majority of Caloglossa species are now distributed, to high-latitude regions, and such an expansion would be associated with acquiring low-temperature tolerance . 相似文献
93.
周荣华 《中国科学:生命科学英文版》1997,40(6):657-664
Using genomicin-situ hybridization (GISH) technique, 7 translocation-addition lines, 6 translocation and translocation-addition lines, 2 ditelosomic
addition lines and 1 translocation line were identified fromTriticum aestivum L. -Psathyrostachys juncea (Fisch.) Nevski intergeneric hybrids, of which translocation-addition and translocation and translocation-addition lines
were not found in other reports. No substitutions and disornic additions were detected in the, hybrids and breakages occurred
in allP. juncea chromosomes studied. Results have shown that the improved GISH technique is a rapid and economical method for use in this
field. 相似文献
94.
The energization of the active sucrose release from bean seed-coat halves was investigated. For this purpose, seed coat tissues adjacent to the apoplastic space were exposed to a variety of treatments and proton and photosynthate release were measured. Fusicoccin (10–5 moll–1) stimulated proton pump activities. Orthovanadate (2×10–4 moll–1) and abscisic acid (10–5 moll–1) diminished the proton extrusion evoked by fusicoccin. Fusicoccin inhibited sucrose release, whereas orthovanadate and abscisic acid stimulated it. Addition of 100 mmoll–1 K+ had a promotory effect on photosynthate unloading, fading away with time. This extra unloading was linearly related to an enhanced proton loss. It was concluded that the photosynthate unloading apparently is not a proton/sucrose antiport and that a pump-leak system for photosynthate release is unlikely. A tentative model for photosynthate/proton symport not directly linked to proton pumping is presented as the mechanism of unloading.Abbreviations ABA
abscisic acid
- CCCP
carbonyl cyanide m-chlorophenyl hydrazone
- DTE
diethioerythritol
- FC
fusicoccin
- MES
2-(N-morpholino) ethanesulfonic acid monohydrate
- NEM
n-ethylmaleimide
- PCMBS
p-chloromercuriphenylsulfonic acid
- TRIS
2-amino-2-(hydroxymethyl) propane-1,3 diol
- VAN
sodium orthovanadate 相似文献
95.
Photosynthetically fixed 14C was analyzed in various chemical fractions from leaves and stems of cottonwood (Populus deltoides Bartr. ex. Marsh.) during dormancy induction. Dormancy was induced by 8-h photoperiods and 20/14°C temperature regimes. Within 4 weeks under short days, terminal buds were set and leaf expansion and stem elongation had stopped. 14C2 was fed to a leaf at Leaf Plastochron Index 7 for 30 min. Either after this 30 min feeding period or after a 48-h translocation period the plants were sampled, freeze-dried, extracted and analyzed for14C. 14C-fixation decreased during dormancy induction from 60% to 17% of the 3.7 MBq 14C applied at 0 week and 8 weeks, respectively. Percentage distribution of 14C in chemical fractions of source leaves reflected leaf age and translocation inhibition. In rapidly growing plants, considerable 14C was incorporated into leaf protein while most of the soluble14C-sugars were either metabolized or translocated out of the leaf. After terminal bud set, the percentage of 14C in the protein and residue fractions decreased rapidly and that in the sugar fraction increased. Percent distribution in stems closely reflected changing metabolic pathways of carbon flow as influenced by dormancy induction. For example, the 14C in structural carbohydrates decreased in 5 weeks under short days from 65 to less than 10% of the 14C recovered in the chemical fractions, thus indicating cambium inhibition. At the same time the percentage of 14C in starch and sugar increased indicating storage. Short term (after 30 min) incorporation of 14C into the protein and starch fractions of leaves changed relatively little throughout the 8-week induction period. In contrast the turnover rates of these fractions (14C present after 48 h) increased considerably after active growth of the whole plant stopped. 相似文献
96.
After foliar application of [4-14C]cholesterol to a Solanum khasianum shrub during a 6-week period, cholesterol was recovered not only from untreated leaves, but also from fruits at three different stages of maturity. In addition to free [4-14C]cholesterol, small amounts of [4-14C]cholesteryl esters but no [4-C14]cholesteryl glycosides were found in the fruits, treated, and untreated leaves. Thus, cholesteryl glycosides are probably not involved in the translocation of cholesterol. The implications of cholesterol translocation in the kinetics of solasodine Production are discussed. 相似文献
97.
Lynn Margulis Peter Mazur Elso S. Barghoorn Harlyn O. Halvorson Thomas H. Jukes Isaac R. Kaplan 《Journal of molecular evolution》1979,14(1-3):223-232
Summary The results of the Viking Biology experiments are best explained by non-biological phenomena: The interaction of the reagents with the materials comprising the regolith. Conditions of water activity, temperature, availability of carbon sources and others in most regions of the planet are too extreme for survival and growth of any known Earth microorganisms. Although the possibility persists that some very unusual form of life is somewhere on that planet the evidence is best interpreted as negative. Even though there is no evidence for current life on Mars, whether or not life ever originated there is not known. 相似文献
98.
Summary Inclusion of sucrose in the solution applied to soybean (Glycine max L. merr.) leaves much reduced the severity of the damage to the leaves from application of urea and, to a lesser extent, from application of phosphorus (P) as orthophosphoric acid. Sucrose had no evident effect on P absorption. Damage to the leaves from joint application of orthophosphoric acid and urea exceeded the sum of the damage caused by the substances individually. Urea did not seem to influence P absorption, but the effect, if any, was not readily determined because nearly all values for P absorption exceeded 90%.Neutralization of orthophosphoric acid with nitrogen-containing organic bases, including choline, guanidine, and guanyl urea, did not prove useful as a technique for increasing the quantity of orthophosphate that could be applied without damage to the leaves.Absorption and translocation of orthophosphate by corn (Zea mays L.) and soybean leaves were not influenced by the pH of the solution within the range from 2 to 10. Absorption of tripolyphosphate by corn leaves decreased with an increase in pH of the solution applied, but translocation of the absorbed P was not influenced by pH. With soybeans, absorption of tripolyphosphate decreased with an increase in pH of the solution. Translocation of P applied to soybean leaves as tripolyphosphate was less than 5% of the amount absorbed within the first 24 hr and decreased with an increase in pH after 10 days. 相似文献
99.
P/2e ratios were calculated from anaerobic chemostat cultures of Paracoccus denitrificans with nitrogenous oxides as electron acceptor. P/2e ratios were calculated, using the Y
ATP
max
values determined for aerobic cultures. When succinate was the carbon and energy source the average P/2e values of the sulphate-and succinate-limited cultures with nitrate as electron acceptor were 0.5 and 0.7, respectively, and of the nitrite-limited culture 0.9. With gluconate as carbon and energy source the average P/2e values of the gluconate-limited with nitrate as electron acceptor and nitrate limited cultures were 0.9 and 1.1, respectively.H+/O ratios measured in cells obtained from sulphate-, succinate, nitrite-, gluconate-and nitratelimited cultures yielded respective average values of 3.4, 4.5, 3.5, 4.8 and 6.2 for endogenous substrates. From our data we conclude that sulphate-and nitritelimitation causes the loss of site I phosphorylation. Nitrite has no influence on the maximum growth yield on ATP. We propose that metabolism in heterotrophically grown cells of Paracoccus dentrificans is regulated on the level of phosphorylation in the site I region of the electron transport chain. 相似文献
100.
B. Thompson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1978,52(5):201-207
Summary Examples are presented to illustrate some of the effects aberrant values, in particular, measurement errors, may have on estimates of the genetic parameters related to selection studies. It is shown that aberrant values may cause observed response to selection pressure to differ considerably from predicted response. Possible dangers of indiscriminate screening are also discussed. 相似文献