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91.
EDMUND L. SEYD 《Biological journal of the Linnean Society. Linnean Society of London》1988,34(4):349-362
A faunal list of oribatid mites collected from the summit of the Cheviot, Northumberland, is given, together with notes on the taxonomy and distribution of several of the species. Special attention is paid to the Arctic-alpine and European-alpine species and the list provides further support for the view that the upland areas of Britain are characterized by a common group of oribatid species. It is suggested that these species may be cold hardy or cold tolerant with relatively high supercooling points, enabling them to survive the winter at these higher altitudes. 相似文献
92.
Richard C. Leegood Carlos A. Labate Steven C. Huber H. Ekkehard Neuhaus Mark Stitt 《Planta》1988,176(1):117-126
Glycerol induced a limitation on photosynthetic carbon assimilation by phosphate when supplied to leaves of barley (Hordeum vulgare L.) and spinach (Spinacia oleracea L.). This limitation by phosphate was evidenced by (i) reversibility of the inhibition of photosynthesis by glycerol by feeding orthophosphate (ii) a decrease in light-saturated rates of photosynthesis and saturation at a lower irradiance, (iii) the promotion of oscillations in photosynthetic CO2 assimilation and in chlorophyll fluorescence, (iv) decreases in the pools of hexose monophosphates and triose phosphates and increases in the ratio of glycerate-3-phosphate to triose phosphate, (v) decreased photochemical quenching of chlorophyll fluorescence, and increased non-photochemical quenching, specifically of the component which relaxed rapidly, indicating that thylakoid energisation had increased. In barley there was a massive accumulation of glycerol-3-phosphate and an increase in the period of the oscillations, but in spinach the accumulation of glycerol-3-phosphate was comparatively slight. The mechanism(s) by which glycerol feeding affects photosynthetic carbon assimilation are discussed in the light of these results.Abbreviations Chl
chlorophyll
- C
i
intercellular concentration of CO2
- P
phosphate
- PGA
glycerate-3-phosphate
- Pi
orthophosphate
- triose-P
sum of glyceraldehyde-3-phosphate and dihydroxyacetone phosphate 相似文献
93.
The aim of this work was to examine the effect of abrupt changes in temperature in the range 5 to 30°C upon the rate of photosynthetic carbon assimilation in leaves of barley (Hordeum vulgare L.). Measurement of the CO2-assimilation rate in relation to the intercellular partial pressure of CO2 at different temperatures and O2 concentrations and at saturating irradiance showed that as the temperature was decreased photosynthesis was saturated at progressively lower CO2 partial pressures and that the transition between the CO2-limited and ribulose-1,5-bisphosphate-regeneration-limited rate became more abrupt. Feeding of orthophosphate to leaves resulted in an increased rate of CO2 assimilation at lower temperatures at around ambient or higher CO2 partial pressures both in 20% O2 and in 2% O2 and it removed the abruptness in the transition between the CO2-limited and ribulose-1,5-bisphosphate-regeneration-limited rates. Phosphate feeding tended to inhibit carbon assimilation at higher temperatures. The response of carbon assimilation to temperature was altered by feeding orthophosphate, by changing the concentrations of CO2 or of O2 or by leaving plants in the dark at 4°C for several hours. Similarly, the response of carbon assimilation to phosphate feeding or to changes in 2% O2 was altered by leaving the plants in the dark at 4°C. The mechanism of limitation of photosynthesis by an abrupt lowering of temperature is discussed in the light of the results.Abbreviations A
rate of CO2 assimilation
-
P
i
intercellular partial pressure of CO2
- RuBP
ribulose-1,5-bisphosphate 相似文献
94.
立枯丝核菌蛋白质电泳图谱研究 Ⅰ.融合群与图谱的相关性 总被引:1,自引:0,他引:1
用来自日本和美国的立枯丝核菌8个融合群11个类群代表菌株进行可溶性蛋白质电泳,其结果表明,各融合群及亚群之间电泳图谱有显著差异,而同一类群菌株的电泳图谱则相似。分析来源于华东等地已鉴定的融合类群117个菌株的电泳图谱显示,同一融合群内菌株,虽然采集地区、寄主植物或致病力不同,其蛋白质图谱仍十分相似;而不同融合类群的菌株,即使在同一田块中同一种寄主植物上引起相似病害,其图谱也显示出明显差异。本文就上述可溶性蛋白质图谱显示的结果与其它研究者在血清学、DNA同源性.酯酶等生化水平上对融合群的研究结果进行了比较和探讨。 相似文献
95.
玉米不同叶位叶片叶绿体超微结构与光合性能的研究 总被引:24,自引:0,他引:24
对玉米植株基部(第3叶),中部(果穗叶)和上部(倒2叶)叶位叶片,进行叶绿体超微结构的观察,并测定了叶绿素含量和光合强度,结果表明,不同叶位叶片叶肉细胞中叶绿体的超微结构,随叶位上升而渐趋复杂化,果穗叶最为显著,向上又趋简单,具体表现为基粒片层的数目随叶位上升而增多基质片层和基质也随之增加,果穗叶最多,向上又趋减少,不同叶位叶片叶绿素含量和光合强度,果穗叶高于其它叶位。 相似文献
96.
我国沙漠中部地区主要不同生态类型植物脯氨酸的累积、光合、呼吸和叶绿素含量 总被引:21,自引:0,他引:21
中生植物脯氨酸含量为0.42mg/g.dw, 低于少浆旱生植物(1.73mg/g.dw)。多浆旱生植物脯氨酸含量最高(7.22mg/g.dw),为前两者的17倍和4倍,两类旱生植物在干旱条件下(非灌溉)脯氨酸含量均高于灌水处理。少浆与多浆旱生植物的光合强度(16.74,14.04CO2mg/g.dw.h)差异不大,而中生植物(37.57mg/g.dW.h)略高于多浆旱生植物(4.73CO2Mg/g.dw.h),与中生植物(7.60Co2mg/g.dw.h)接近,光合/呼吸值,少浆,多浆与中生植物分别为2.50,3.09和4.59,说明中生植物的合成明显大于消耗,季节动态中,中生植物显著高于两类旱生植物,叶绿素总量三类植物差异甚微。 相似文献
97.
98.
Koji Sode Nobuaki Hori Yoichi Mikami Isao Karube 《Biocatalysis and Biotransformation》1988,2(1):51-57
Asymmetric reduction of 2,6,6,-trimethyl-2-cyclohexene-l,4-dione (4-oxoisophrone) to (6R)-2,2,6-trimethyl-1,4-cyclohexane-dione((3R)-dihydro-4-oxoisophorone) was catalysed by immobilized thermophilic bacteria, Thermomonospora curvata JTS 321. Because of leakage of entrapped cells from gel beads during reactions using culture medium, we optimized the medium to allow the microbial conversion under conditions of controlled cell growth. Of the media screened, liver infusion medium was found to be the most suitable and microbial conversion was achieved without cell leakage from the immobilized gels. Immobilized T. curvata cells were repeatedly used for the asymmetric reduction of 4-oxoisophorone, more than 15 times, with an extent of conversion of 50%. 相似文献
99.
Background processes at the population level during succession in grasslands on sand 总被引:1,自引:0,他引:1
Two population characteristics, reproductive allocation (RA) and the intensity of photosynthesis, were investigated in the successional stages of the sandy grassland communities of the Great Hungarian Plain. Most of the species studied changed their allocational response as succession advanced. Compound path schemes, as casual models, were constructed and analysed for describing intra-individual effects (influence of assimilating organs and root mass of the plant sampled) as well as the phytosociological effects on RA. In pioneer stages, the high values of path coefficients show that the effect of assimilating organs is responsible for the variability of RA. It is also shown that annuals and perennials exhibit different behaviour as to the regulation of RA. It seems that-in terms of path analysis-the reproduction of annuals is influenced by internal factors only. In case of perennials, an external (namely phytosociological) regulation was also observed. It is suggested that successional stages play a role in regulating the photosynthetic intensity of both the dominant species and the whole plant assemblage.Abbreviations RA =
Reproductive Allocation 相似文献
100.