分子系统发育对中国芸香科分类的贡献

The treatment of Rutaceae in the Chinese flora chose to follow Engler in recognizing Rutoideae and Toddalioideae as two separate subfamilies. Morphological and chemical comparisons, however, suggested grouping those two subfamilies in one subfamily, Rutoideae. This move has received support from molecular phylogenetic analyses, which also showed that the Chinese taxa in Euodia should be placed in Tetradium and Melicope following Hartley. Investigations into the chemistry and molecular phylogeny of Murraya also indicated that the species in the section Bergera without yuehchukene should be removed from Murraya. These findings clearly show the value of molecular cladistics to the taxonomy of Rutaceae in China and also directions for further investigations. Key words Bergera, Euodia, Melicope, Murraya, Rutaceae, Rutoideae, Tetradium, Toddalioideae.     

Effects of Ca2+ and Cd2+ on the Carbohydrate Metabolism in Sugar Beet (Beta vulgaris)

Sugar beet (Beta vulgaris L. cv. Monohill) were cultivated ina nutrient solution with different combinations of Ca²⁺ (36,180, 720 or 3560µM) and Cd²⁺ (0, 1, 5 or 20µM).The dry and fresh weights, the content of Ca²⁺ and Cd²⁺ , sucrose,fructose, glucose and starch in 5-week-old plants was analysedas well as the rate of [¹⁴C]-sucrose uptake in discs from 3-month-oldstorage roots. The carbohydrate metabolism was indirectly affectedby the presence of calcium or cadmium. Cadmium caused a diminisheddry weight and carbohydrate concentration. The dry weight wasunaffected by the Ca²⁺ level but the carbohydrate distributionbetween storage and growth processes was affected; at low Ca²⁺in the tissue, the growth was retarded and the level of storagecarbohydrate increased, while at high Ca²⁺ the opposite wasfound. The [¹⁴C]-sucrose uptake decreased in tap roots cultivatedat low Ca²⁺ . Long term exposure to Cd²⁺ also decreased thesucrose uptake in tap roots. Direct Cd²⁺ addition to the assaymedium, however, increased the sucrose uptake, probably at thetonoplast, while Ca²⁺ had no transient effect on the uptake.Cadmium increased the Ca²⁺ concentration in the plant, but Ca²⁺did not affect the net-uptake of Cd²⁺. Key words: Sugar beet, cadmium uptake, calcium uptake, carbohydrate formation, growth     

Common Cuckoo Cuculus canorus and host behaviour at Reed Warbler Acrocephalus scirpaceus nests

This study is based on continuous video recordings made at 53 Reed Warbler Acrocephalus scirpaceus nests each day during the laying period. Egg-laying by the Common Cuckoo Cuculus canorus was recorded in 14 (26.4%) of these nests. By analysing the activity of the host birds around and at the nest, we found that this is probably not the only cue used by the Common Cuckoo when locating suitable nests to parasitize. Furthermore, in most cases there was no significant difference between the length of time the host birds spent at the nest in the morning and afternoon, thus providing little support for the hypothesis that the Common Cuckoo lays in the afternoon because it is less likely to be seen by the nest owners then. Parasitized Reed Warblers rejected the Common Cuckoo egg more frequently when they observed the parasite at their nests. However, contrary to what should be expected, most Common Cuckoos laid their eggs in the presence of the host(s), and in general their egg-laying behaviour (for example duration of stay at the nest) was less secretive than described earlier. When partially depredating host clutches, Cuckoos showed the same behavioural pattern at parasitized and unparasitized nests, indicating that the latter may act as a potential reserve for egg-laying.     

Contribution of molecular cladistics to the taxonomy of Rutaceae in China*

The treatment of Rutaceae in the Chinese flora chose to follow Engler in recognizing Rutoideae and Toddalioideae as two separate subfamilies. Morphological and chemical comparisons, however, suggested grouping those two subfamilies in one subfamily, Rutoideae. This move has received support from molecular phylogenetic analyses, which also showed that the Chinese taxa in Euodia should be placed in Tetradium and Melicope following Hartley. Investigations into the chemistry and molecular phylogeny of Murraya also indicated that the species in the section Bergera without yuehchukene should be removed from Murraya. These findings clearly show the value of molecular cladistics to the taxonomy of Rutaceae in China and also directions for further investigations.     

Uptake and Physiological Effects of Cadmium in Sugar Beet (Beta vulgaris) Related to Mineral Provision

Sugar beet seedlings (Beta vulgaris L. cv. Monohill) were grownfor 14 d on a nutrient solution based on the nutrient proportionsin healthy plants. Nutrients were supplied either once at relativelyhigh concentrations, or in small amounts with a daily incrementalincrease of 0?15 or 0?20 in accordance with an exponential growthrate. Cadmium (0, 0?6, 2?3, 50 or 20?0 µmol) was introducedeither by a single addition or in daily increments of 0?15 or0?20. Cadmium uptake, expressed as a percentage of total Cd²⁺supplied, decreased with increasing total C^d2+ content and withdecreasing availability of nutrients. With a daily supply ofcadmium, net uptake, transport and content per unit of dry weightin roots and shoots were related to the total Cd²⁺ supplied.Cadmium caused growth retardation, increased root/whole-plantratio, and decreased root-tip respiration and photosynthesis.At high initial nutrient concentrations, Cd²⁺ decreased thecontents of sucrose, glucose, fructose, and starch per unitof dry weight. The opposite was found if nutrients were addeddaily. In the latter case, the dry weight/fresh weight ratioalso increased. The effects of cadmium were related to [Cd²⁺]in proportion both to the root absorption area and to the nutrientconcentration. Key words: Sugar beet, mineral provision, cadmium uptake, sugar formation, growth     

Contribution of molecular cladistics to the taxonomy of Rutaceae in China

The treatment of Rutaceae in the Chinese flora chose to follow Engler in recognizing Rutoideae and Toddalioideae as two separate subfamilies. Morphological and chemical comparisons, however, suggested group-ing those two subfamilies in one subfamily, Rutoideae. This move has received support from molecular phyloge-netic analyses, which also showed that the Chinese taxa in Euodia should be placed in Tetradium and Melicope following Hartley. Investigations into the chemistry and molecular phylogeny of Murraya also indicated that the species in the section Bergera without yuehchukene should be removed from Murraya. These findings clearly show the value of molecular cladistics to the taxonomy of Rutaceae in China and also directions for further inves-tigations.