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81.
Synopsis We investigated the ability of two congeneric species of sunfish to learn to forage on a novel prey item in feeding arenas
containing structured habitats. Eight bluegill sunfish and eight pumpkinseed sunfish were given the opportunity to forage
on whiteworms daily for 10 days. Each day, several behavioural measures were recorded for each fish. Both species of sunfish
learned to feed over the 10-day period but the bluegill sunfish learned to feed more quickly than the pumpkinseed sunfish.
Pumpkinseeds, however, attained a higher level of foraging efficiency. The differences in learning and foraging efficiency
were related to body morphology. 相似文献
82.
从大花翠雀(Delphinium grandiflorum L.)的地上部分分离到两个微量的新二萜生物碱——大花翠雀辛(grandifloricine,Ⅰ)和大花翠雀亭(grandifloritine,Ⅱ)。通过分析光谱信息测定了它们的化学结构,并通过化学反应转变为 takaosamine 而得到确证。 相似文献
83.
More than 750 plants were regenerated from protoplasts isolated from microspore callus-derived cell suspensions of the Mediterranean japonica rice Miara, using a nurse-feeder technique and N6-based culture medium. The mean plating efficiency and the mean regeneration ability of the protocalluses were 0.5% and 49% respectively. Flow cytometric evaluation of the DNA contents of 7 month old-cell and protoplast suspensions showed that they were still haploid. Contrastingly, the DNA contents of leaf cell nuclei of the regenerated protoclones ranged from 1C to 5C including 60% 2C plants. This was consistent with the morphological type and the fertility of the mature plants. These results and the absence of chimeric plants suggest that polyploidization occurred during the early phase of protoplast culture.Abbreviations BAP
6-benzylamino purine
- 2,4-D
2,4-dichlorophenoxyacetic acid
- FDA
fluorescein diacetate
- GA3
gibberellic acid
- NAA
-naphthaleneacetic acid
- PAS
periodic acid Schiff
- PCM
protoplast culture medium
- PCV
packed cell volume 相似文献
84.
Mitsuyasu Hasebe Rumiko Kofuji Motomi Ito Mikio Kato Kunio Iwatsuki Kunihiko Ueda 《Journal of plant research》1992,105(4):673-679
Partial nucleotide sequences of the large subunit of ribulose-1,5-bisphosphate carboxylase (rubisco) gene (1333 base pairs:
about 90% of the gene) from several seed plants were determined. Phylogenetic trees based on amino acid sequences were inferred
by using the neighbor joining and maximum likelihood methods. The results indicate (1) monophyly of gnetum group (Ephedra, Gnetum, Welwitschia), (2) monophyly of extant gymnosperms containing gnetum group, which contradicts the results of morphological data. 相似文献
85.
The morphological development and N uptake patterns of spring barley (Hordeum vulgare L.) genotypes of Northern European (Nordic) and Pacific Northwest US (PNW) origin were compared under two diurnally fluctuating root temperature regimes in solution culture. The two regimes, 15/5°C and 9/5°C day maximum/night minimum temperatures, simulated soil temperature differences between tilled vs. heavy-residue, no-till conditions, respectively, observed during early spring in eastern Washington. Previous field experiments indicated that some of the Nordic genotypes accumulated more N and dry matter than the PNW cultivars during early spring under no-till conditions. The objective of this experiment was to determined whether these differences 1) are dependent on the temperature of the rooting environment, and 2) are correlated with genotypic differences in NH4
+ and NO3
– uptake. Overall, shoot N and dry matter accumulation was reduced by 40% due to lower root temperatures during illumination. Leaf emergence was slowed by 14 to 22%, and tiller production was also inhibited. All genotypes absorbed more ammonium than nitrate from equimolar solutions, and the proportion of total N absorbed as NH4
+ was slightly higher in the 9/5°C than the 15/5°C regime. A Finnish genotype, HJA80201, accumulated significantly more shoot N than the PNW cultivars, Clark and Steptoe, and also more than a Swedish cultivar, Pernilla, in the 9/5°C regime. In the 15/5°C regime Steptoe did not differ in shoot N from the Nordic genotypes, while Clark remained significantly lower. These differences were not correlated to relative propensity for N form. Root lengths of the Nordic genotypes were significantly greater than the PNW genotypes grown under the 9/5°C regime, while the root lengths in the warmer root temperture regime were not significantly different among genotypes. Higher root elongation rates under low soil temperature conditions may be an inherent adaptive mechanism of the Nordic genotypes. Overall, the data indicate that lower maximum daytime temperatures of the soil surface layer likely account for a significant portion of the growth reductions and lower N uptake observed in no-till systems. 相似文献
86.
Dicotyledonous plants subjected to Fe-deficiency stress can decrease pH in the rhizosphere by proton excretion and reduce ferric iron by an activated reduction system in the plasma membranes of the root or by reductants released from the roots. The efficiency by which these plants take up Fe may strongly depend on their cation-anion balance. This study presents results of two experiments conducted to evaluate the effect of K, growth stage and cultivar on ionic balance and Fe acquisition of peanut (Arachis hypogaea L.) plants.Potassium applications to the high calcareous soil (30.3% CaCO3) favoured proton release, but did not ameliorate plant Fe acquisition. At the earliest stages of plant growth, anion uptake exceeded cation uptake due to intensive N uptake. With time, a shift in the ionic balance was observed as a result of predominant cation uptake. It appears that the relationship between H/OH-ion release and Fe nutrition of peanut plants is actually a complex phenomenon under soil conditions and depends on some soil parameters, such as CaCO3 content. Even by enhanced H-ion release Fe nutrition of plants can be impaired if soil CaCO3 is too high. 相似文献
87.
Iron-efficient (WF9 corn and Coker 227 oat) and Fe-inefficient (ys1 corn and TAM 0–312 oat) cultivars were comparatively tested for their response to Fe-deficiency stress induced by the use of either ferrous or ferric chelators. Corn and oats were grown in 20 M Fe with 0, 60, and 120 M BPDS and 40 M Fe with 0, 120, and 240 M BPDS and 20 M Fe with 0 and 40 M EDDHA. All four cultivars tested, both Fe-efficient and Fe-inefficient, continuously reduced Fe3+ to Fe2+ at a low level as evidenced by the production of Fe2+ (BPDS)3 in test nutrient solutions over time. Severity of chlorosis increased as more BPDS was added to the nutrient solutions for both WF9 and ys1 corn, but unlike corn, Coker 227 and TAM 0-312 oats were both able to obtain Fe from the Fe2+ (BPDS)3 complex and were less chlorotic as a result. In short-term (4-hour) in vivo measurements, iron-stressed WF9 (Fe-efficient) corn reduced more Fe3+ to Fe2+ than similarly stressed ys1 corn, Coker 227 oat or TAM 0-312 oat. Thus, at the same time that Fe-efficient WF9 corn reduces more Fe than the other cultivars, it is also unable to compete with BPDS for that Fe in the nutrient solution. These differences coupled with the observation that only Coker 227 oat produced measureable iron solubilizing substances (phytosiderophores) suggest that these two species differ in their mechanisms for obtaining Fe during Fe-deficiency stress. 相似文献
88.
Aluminium,boron and molybdenum availability and uptake by rice in acid sulfate soils 总被引:1,自引:0,他引:1
Although Al toxicity is believed to be a problem in acid sulfate soils cropped to rice (Oryza, sativa L.), little is known about the behavior of other trace metals such as B and Mo in these soils. The objectives of this study were to measure the availability of Al, B, and Mo in these soils, to determine what governs the availability of these metals and to investigate the relationships between metal availability and uptake by rice. Metal availability and uptake by rice were evaluated in 134 flooded acid sulfate soils in the Central Plains region of Thailand and in a growth chamber study using 50 of the same soils. Soil and plant metal analyses were conducted at the panicle differentiation stage of growth in both studies and in the soil prior to transplanting in the growth chamber study. Metal activities were determined with GEOCHEM. The mineral phases believed to be governing Al3+ activities were jurbanite under low pH conditions and amorphous Al(OH)3 at high pH. The Al chemistry is believed to be intimately linked to the redox-pH cycle, which is driven by the monsoonal climate. Mortality of rice associated with Al toxicity was observed under field and growth chamber conditions. Interference in P uptake and/or assimilation was believed to be the mechanism of Al toxicity. Activities of B(OH)
4
–
and B(OH)
3
0
were found to be highly correlated to pH and ionic strength, respectively, with the latter being the dominant B ion found in these soils. Activities of MoO
4
2–
were positively correlated to pH and appeared to be controlled by wulfenite. Leaf Mo contents were found to be positively correlated with MoO
4
2–
activity. 相似文献
89.
A field experiment was conducted for five consecutive years to determine upland rice (Oryza sativa L.) and common bean (Phaseolus vulgaris L.) response to eight P sources at three P rates in an Oxisol of Central Brazil. The P sources tested were triple superphosphate
(TSP), Arafertil phosphate partially acidulated (APPA), phosphate of Patos partially acidulated (PPPA), phosphate of Araxa
concentrated (PAC), phosphate of Catalao (PC), phosphate of Jacupiranga (PJ), phosphate of Patos de Minas (PPM), and phosphate
of Abaete (PA). All phosphate rock sources were of Brazilian origin. The P rates used were 87, 174 and 262 kg P ha-1. Yield response to P sources and rates varied from crop to crop. Rice and bean yields were significantly correlated with
Bray 1 P, but not Mehlich 1 P. In the first year, TSP and the two partially acidulated phosphate rocks (APPA, PPPA) produced
higher grain yields. In the second year and all remaining years of the experiment, the efficiency of phosphate rock sources
as measured by grain yield was equivalent to TSP or partially acidulated P sources. The results suggest that these phosphate
rock sources could be used in rice-bean rotations on Brazilian Oxisols. Yield losses in the first year could be partially
offset by the addition of a small amount of soluble P. 相似文献
90.
An experiment to study the effects of Mg nutrition on root and shoot development of the Al-sensitive sorghum (Sorghum bicolor (L.) Moench) genotype CV323 grown in pots of sandy loam under different acid soil stress is reported. This experiment had
a factorial design: four rates of liming were combined with four rates of Mg fertilization. When no Mg was added, the pH of
the soil solutions (collected in ceramic cups) increased from 4.0 (unlimed) to 4.2, 4.7 and 5.9 at the increasing rates of
liming. After 30 days of growth dry matter yields of the limed treatments were 40%, 115% and 199% higher than that of the
unlimed treatment. Without liming and at the highest liming rate, adding Mg did not affect plant biomass significantly. At
the two intermediate levels of liming, however, 11.3 mg extra Mg per kg soil increased dry matter yield to the same levels
as found at the highest liming rate. Concentrations of Mg in the soil solution rose after Mg was added and fell when lime
was added, but adding both Mg and lime increased Mg concentrations in the plant shoots. In plants of the limed treatments,
dry matter yield was correlated closely with the Mg concentration in the shoot. This was not so in the unlimed treatment.
Furthermore, in the unlimed treatments root development was inhibited, but reduced Mg uptake by the plants resulted mainly
from the direct effect of Al- (or H-) ions in the soil solution rather than from impaired root development. It is concluded
that Mg fertilization counteracted the interfering effects of Al- and H ions on Mg uptake. 相似文献