春化冬小麦的玉米赤霉烯酮结合蛋白(简报)(英文)

玉米赤霉烯酮(Zearalenone,简称ZEN)是八十年代初从高等植物中鉴定出的一种微量生理活性物质,已证明它在植物成花过程中起重要作用。为了阐明玉米赤霉烯酮的作用机制,我们用放射配体竞争结合分析法研究了春化冬小麦的ZEN特异结合蛋白。结果表明在春化冬小麦胚芽中存在着可溶性的ZEN特异结合蛋白(ZBP)。结合反应的pH范围在6-8,加热、蛋白酶和尿素处理破坏结合活性。玉米赤霉烯酮的同系物α-玉米赤霉醇和β-玉米赤霉醇,以及动物雌性激素雌二醇可与ZEN竞争结合ZBP。其它植物激素不能与ZBP发生竞争结合。蔗糖密度梯度离心分析表明ZBP沉降于4-5S区。     

作物群体CO2通量和水分利用效率的快速测定

In this paper,Eddy Correlation (EC) method was employed to measure the latent heat and CO₂ flux density and to calculate Water Use Efficiency (WUE) of winter wheat community in Yucheng district,Shandong Province in 1997.The results showed that the CO₂ flux density had an obvious diurnal change,with a maximum about1.5 mg·s^-1·m^-2,which appeared at about 9:00～10:00 am in general.The WUE of wheat community presented a fall trend from morning to afternoon,and the CO₂ flux density and WUE also had an obvious seasonal change,being lower in the early and late growth stages,and higher in the middle growth stage.The ranges of daily mean CO₂ flux density and WUE were 0.2～0.9 mg·s^-1·m^-2 and 5～20 gCO₂·kg^-1 H₂O,respectively.     

Chimpanzee (Pan troglodytes) Seed Dispersal in an Afromontane Forest: Microhabitat Influences on the Postdispersal Fate of Large Seeds1

We examined the postdispersal fate of large seeds (≥5 mm) dispersed by chimpanzees in an afromontane forest to evaluate aspects of the effectiveness of seed dispersal by chimpanzees, Pan troglodytes. We assessed the influence of six microhabitat characteristics on seed persistence and germination in seeds dispersed in chimpanzee feces and “wadges.” A total of 257 fecal samples and 56 wadges were located over a 4‐mo period by tracking a semi‐habituated chimpanzee community on day follows. Forty‐nine (19.1%) of the fecal samples contained large seeds from five different tree species. The majority of fecal samples with seeds contained seeds from the mature forest tree Olea capensis (Oleaceae) (83.7%). Forty‐two wadges (75%) contained seeds from the mature forest tree Syzygium guineense (Myrtaceae). Seeds were monitored at their deposition site for removal and germination up to 49 d following deposition. We collected data on the microhabitat surrounding each fecal and wadge sample. Multivariate analyses indicated that while fecal and wadge samples were not clustered into particular microhabitats, there was little overlap in the microhabitats in which wadges and fecal samples were deposited. Significantly more seeds persisted over 49 d in wadges (67.9%) than in feces (30.3%). Elevation was the only microhabitat variable determined to have a significant influence on seed persistence, whereas slope was determined to have a significant influence on germination.     

Foraging conditions, tooth wear and herbivore body reserves: a study of female reindeer

Several aspects of the life history of reindeer (Rangifer tarandus) are related to the nutritional condition of the animals. Moreover, compensatory growth and fattening in summer decreases with age. The interaction of tooth wear and the standing crop of lichens on age-related variation in body size and tissue reserves was examined to evaluate the proximate causes of density-dependent food limitation on life history parameters in female reindeer. Studies in nine semi-domesticated free-ranging reindeer herds showed that molar height depended on the mean standing crop of terrestrial lichens in winter habitats. The extent of tooth wear had the strongest effect on body reserves among the oldest females (11–14 years). This indicates that severe tooth wear limits the animals′ ability to process food efficiently and, hence, to maintain their body reserves. Both tooth wear and the biomass of lichens influenced body mass in old females, probably because on heavily exploited winter ranges reindeer had to use higher proportions of lower-ranking coarser foods, especially dwarf shrubs. Received: 1 December 1997 / Accepted: 13 July 1998     

Fish recruitment, dispersal, and trophic interactions in a heterogeneous lotic environment

I examine how dispersal of juvenile creek chubs (Semotilusatromaculatus) from beaver ponds into adjacent stream environments interacts with temporal abiotic variability to influence fish foraging, growth, and long-term persistence in the lotic ecosystem. Minnow trapping in upstream and downstream beaver ponds, along with weir traps used to monitor directional movement, indicated that most chubs colonized the stream from the downstream beaver pond. Large annual fluctuations in density of age 0 creek chubs occurred in the stream over a 10-year sampling period. Multiple regression analysis indicated that stream temperature, precipitation, and the density of reproductive creek chubs were not correlated with summer density of age 0 chubs in the stream. The factor most strongly associated with increased density of age 0 creek chubs was creation of the downstream beaver pond during the 6th–7th years of the study, suggesting dispersal from the pond was the primary factor determining age 0 fish density in the stream. Most individuals in the strong year classes neither persisted in the stream through their first winter nor resulted in an increased abundance of older age classes in later years. Comparison of age 0 fish density in summer to the proportion of fish surviving to age 1 in spring suggested that overwinter mortality was density dependent. Furthermore, a comparison of the size structure for age 0 individuals in summer to age 1 individuals the following spring indicated that winter mortality was size dependent. Experiments in an artificial stream adjacent to the natural channel revealed that fish growth was strongly density dependent, decreasing as fish density increased across both spring and summer, and elevated and low discharge. The decline in invertebrate prey captured by the fish and the subsequent decline in fish growth appeared to be particularly pronounced under low discharge in summer. Changes in juvenile creek chub density had no significant effect on benthic insect or crustacean abundance, suggesting that exploitative competition for limited invertebrate drift resources was a more important cause of density- dependent growth than depressed local benthic invertebrate abundance. These results suggest that lotic regions adjacent to beaver ponds act as potential reproductive “sinks” for dispersing juveniles confronting seasonal and flow-mediated restrictions on resource acquisition and growth, and the occurrence of seasonal bottlenecks to their survival, especially harsh winter conditions. Received: 9 September 1996 / Accepted: 8 August 1997     

Tool-set for termite-fishing and honey extraction by wild chimpanzees in the Lossi Forest, Congo

The use of perforating sticks and flexible stalks in combination for termite fishing and a complex tool-set of three components used sequentially (stout chiel, bodkin, and dip-stick) to penetrate melipone and ground-dwelling bee hives byPan troglodytes troglodytes are documented or, inferred from circumstantial evidence. Functionally, termite extraction tools were similar to other locations in west and central Africa, but the plants and the number of raw material species used were different. Tools varied in the degree of modification (fraying ends). Chimpanzees in the Lossi forest seem to be able to use the tools not in a stereotyped fashion, but in a flexible, insightful way. The extraction of Melipone honey using large pieces of wood as pounding tools has rarely been recorded elsewhere. The most impressive technological solution to the honey-getting problem by wild chimpanzees was shown by this study. This is the only known, use of a tool-set of three components in sequence to extract honey by wild chimpanzees.     

Molecular Cloning of a Vernalization related cDNA Clone (Vrc) of Vrc79 in Winter Wheat (Triticum aestivum L.)

Vernalization is an essential factor in the flowering development of cold-required plants. There is a key stage of nucleic acid metabolism in the process of vernalization in winter wheat. To probe into the molecular determinants of vernalization, a cDNA library presumably enriching vernalization-related genes was prepared by specially expressed mRNAs from winter wheat ( Triticum aestivum L. cv. Jingdong No. 1) plumules at the key stage of 21 d vernalization being recovered as cDNAs after subtraction with mRNAs from nonvernalized and devernalized plumules. One vernalization-related cDNA clone (Vrc), Vrc79, which was only expressed at the key stage of 21 d vernalization, but not at other stages of nonvernalization, 4 d vernalization and devemalization, was isolated by differential screening of the library, and shown to be a vernalization-specific clone by Northern blot. Result of homology search suggested that Vrc79 was a novel gene identified in higher plant which was different from the cold-stress-induced genes and might play an important role in the floral induction in vernalization-requiring plants.     

Analysis of spatial and yearly variation in winter survival of winter wheat

 Four years of winter survival data for winter wheat (Triticum aestivum L.) were collected on a loam soil located on the Central Experimental Farm at Ottawa, Ontario (45° 23′N, 75° 43′W). The site was low-lying and subject to frequent winter flooding and ice sheet formation. It appeared level although there was microtopographic variation with a range in elevation of approximately 0.15 m. The objective of the study was to gain insight into factors which might affect winter survival. Two varieties, a soft white and a hard red winter wheat, were planted in September. Crop establishment was measured in late fall and the percentage survival was measured in April of the following year. We assumed the large spatial differences in survival were not totally random, but rather were affected by spatial variation in environmental factors such as snow and ice depth, soil moisture and temperature. Hourly measurements of soil temperature at a depth of 0.05 m were recorded throughout the fall, winter and spring. Fall and spring soil moisture at the same depth were measured on the plot, as well as snow and ice depth at selected times throughout the winter. Measurements were taken on a grid covering the plot to help explain spatial variation in survival. In addition, detailed measurements of elevation were taken on a grid. Meteorological data were available from the nearby weather site. While soil temperatures were never low enough to kill plants according to the CERES model, the spatial variation in winter survival was associated with differences in elevation and the resulting surface drainage patterns. Received: 23 March 1998/Accepted: 21 October 1998     

Protoplast Culture and Plant Regeneration of Winter Wheat (Triticum aestivum L.)

Suspension cultures were established from embryogenic calli derived from cultured anthers of cv. Jinghua No.1 and mature embryos of cv. Youmangbai No. 7, respectively. After being isolated and cultured in WPMI, protoplasts began to form cell walls within 1 day post-isolation, followed by cell division observed between 2–3 days. A division frequency of 22.0% was estimated on the 7th day of culture, and 43.7% on the 14th day. During 10–15 days after the initiation of culture, a large number of cell aggregates emerged, with 0.5–0.8% of plating efficiency. Protoplast-derived calli grew up to lmm or more in diameter when cultured for 4 weeks, and eventually gave rise to green plants through embryogenesis and organogenesis after being transferred to differentiation media. Plant regeneration from protoplasts was already obtained from Jinghua No.l, and protoplast-derived calli from Youmangbai No.7; an experiment on organ differentiation for the latter is under way. A few factors affecting the protoplast cultures were also studied.