中国主要产区何首乌以二苯乙烯苷含量为指标的种质评价

采集我国几大主要产区的野生何首乌及部分栽培品，采用高效液相色谱法(HPLC)对其特征性成分2，3，5，4’-四羟基二苯乙烯-2-O-β-D-葡萄糖苷的含量进行测定，分析了6个野生居群和2个栽培居群以及同一居群同一生长环境不同年限的样品和同一居群同一年限在不同环境条件下生长的样品。实验结果表明：采自广西的一种何首乌药材原植物是何首乌的一个变种棱枝何首乌(P.multiflorum Thunb.var angulatum S.Y.Liu)，而且其中2，3，5，4’-四羟基二苯乙烯-2-O-β-D-葡萄糖苷含量较低；贵州、湖北居群2，3，5，4’-四羟基二苯乙烯-2一O—B—D-葡萄糖苷含量较高，四川、河南较低；另外还发现，种质的不同，年限的差异及不同环境是影响2，3，5，4’-四羟基二苯乙烯-2-O—β—D-葡萄糖苷积累的重要因素。     

Testing the Efficiency of Pollination Bag Materials

Crossing bags manufactured from three grades of polyester and three types of paper bags were tested for their permeability to grass pollen. Bags were placed on L. perenne plants of known PGI isozyme genotype. Any pollen passing through the crossing bag and pollinating the plant was detected by assaying its progeny for PGI isozymes. The results obtained allowed differentiation of the various materials for their suitability for pollen proofing.     

填埋场陈垃圾对黑麦草种子发芽的影响

非正规垃圾填埋场的治理和陈垃圾的资源化利用是环保领域一项重要而迫切的任务。选择黑麦草作为试验对象,采用种子发芽的陆生生态毒理方法,研究陈垃圾对植物发芽的影响,以期为陈垃圾利用和非正规垃圾填埋场治理提供一种新的思路。培养基质中陈垃圾的比例分别为20%、80%和100%,使用蒸馏水和土壤作为对照。试验结果表明:陈垃圾的使用能够显著提高黑麦草种子的发芽势和发芽率,但黑麦草种子的发芽势和发芽率随着陈垃圾用量的增加呈现先增大后减小的特征,陈垃圾在培养基质中的最佳比例为80%,与空白和使用土壤作为培养基质相比,发芽率分别提高了34.3%和20.9%,发芽势分别提高了52.0%和24.0%。培养基质中添加陈垃圾有利于黑麦草种子根、芽的发育和生长,在培养基质中陈垃圾的比例为80%的条件下,黑麦草种子的根长、芽长和芽的鲜质量分别比使用土壤时增加了50.0%、46.9%和74.0%。因此,将稳定后的陈垃圾用于草坪种植是可行的,这为陈垃圾的资源化利用提供了一条新的途径。     

Field assessment of thermal after-ripening time for dormancy release prediction in Lolium rigidum seeds

Dormancy release was studied in four populations of annual ryegrass (Lolium rigidum) seeds to determine whether loss of dormancy in the field can be predicted from temperature alone or whether seed water content (WC) must also be considered. Freshly matured seeds were after‐ripened at the northern and southern extremes of the Western Australian cereal cropping region and at constant 37°C. Seed WC was allowed to fluctuate with prevailing humidity, but full hydration was avoided by excluding rainfall. Dormancy was measured regularly during after‐ripening by germinating seeds with 12‐hourly light or in darkness. Germination was lower in darkness than in light/dark and dormancy release was slower when germination was tested in darkness. Seeds were consistently drier, and dormancy release was slower, during after‐ripening at 37°C than under field conditions. However, within each population, the rate of dormancy release in the field (north and south) in terms of thermal time was unaffected by after‐ripening site. While low seed WC slowed dormancy release in seeds held at 37°C, dormancy release in seeds after‐ripened under Western Australian field conditions was adequately described by thermal after‐ripening time, without the need to account for changes in WC elicited by fluctuating environmental humidity.     

Mineral composition of kenhy tall fescue as affected by nutrient solution concentrations of Mg and K

Four greenhouse sand culture experiments were conducted with Kenhy tall fescue, a Lolium multiflorum X Festuca arundinacea hybrid derivative. These experiments were conducted to characterize mg accumulation and the chemical composition of Kenhy under various combinations of Mg, K, and N solution concentrations. Of primary interest was the shape and magnitude of response of tissue Mg concentration to solution K levels and potential for Mg accumulation that exists in Kenhy under low solution K levels. Analyses were made for Mg, K, Ca, Na, N, and nitrate.

Increased Kg concentrations were observed with increased solution Mg. Increased solution K was in all cases associated with lower concentrations of Mg. Under conditions of low solution K (0.125 mM) and adequate Mg (0.25 mM), Mg accumulation exceeded 1.0%. Increased solution N was associated with decreased Mg concentrations. Both the linear and quadratic components of Mg solution concentration contributed significantly to increased tissue Mg. Hawever, the linear component of K solution concentration was sufficient to account for decreased tissue Mg. The reduction of tissue Mg to solution K was greater at higher concentrations of K.

Potassium accumulation significantly increased with increased solution K. Increased solution Mg was associated with lower tissue K in which the greatest reduction in K accumulation occurred with the first Mg addition.

Calcium accumulation decreased with increased solution K. Higher solution Mg was associated with lower tissue Ca levels while higher levels of N were associated with increased tissue Ca. Sodium accumulation was significantly reduced by increased K concentrations but neither Mg nor N was effective in consistently altering tissue Na concentrations.

From these experiments it is evident that Kenhy tall fescue has the absorptive capability for high levels of Mg under conditions of low levels of solution K. However, even small increments of solution K were shown to be capable of substantially reducing the Mg content, Thus, the selection of forage grasses for Mg absorptive capability must be conducted under conditions of high solution K, if large improvements on present forage materials are to be obtained. In addition, the inverse relationship between Mg and K present in Kenhy seedlings confirms the need to consider K fertilization recommendations in attempting to increase forage Mg durirg the grass tetany period.     

Soil N contributes to the oscillations of the white clover content in mixed swards of perennial ryegrass under conditions that simulate grazing over five years

The effect of the initial N-supplying capacity of soils (SoilN, 90–230 kg N ha^–1 year^–1) was tested on the dry-matter and N yields of pure or mixed white clover and perennial ryegrass swards, managed under simulated grazing over a 5-year period. The cumulated N harvested in the mixed swards was similar, both for white clover and perennial ryegrass, but the proportion of white clover showed oscillations over a 2-year period. In the first year, the SoilN effect was similar to that of fertilizer N. During the course of the experiment, the effect was always positive on the pure perennial ryegrass sward, alternately negative and nil for the white clover in the mixed sward and alternately positive and nil for the perennial ryegrass in the mixed sward; the period of these oscillations was 2 years. From the third regrowth period after sowing, the ratio between the actual N concentration and the concentration non-limiting to growth for the perennial ryegrass in the mixed sward, increased above that of the pure perennial ryegrass sward. It was in turn greater in the soils that were initially poor and then greater in those that were initially rich in soil N. The periodic oscillation of the initial SoilN effects implies that the initial SoilN gradient was alternately compensated and restored. It was concluded that N fluxes are partly responsible for the temporal oscillations in the proportion of white clover in mixed swards.     

An evaluation of four crop : weed competition models using a common data set

Summary To date, several crop : weed competition models have been developed. Developers of the various models were invited to compare model performance using a common data set. The data set consisted of wheat and Lolium rigidum grown in monoculture and mixtures under dryland and irrigated conditions. Results from four crop : weed competition models are presented: almanac , apsim , cropsim and intercom . For all models, deviations between observed and predicted values for monoculture wheat were only slightly lower than for wheat grown in competition with L. rigidum , even though the workshop participants had access to monoculture data while parameterizing models. Much of the error in simulating competition outcome was associated with difficulties in accurately simulating growth of individual species. Relatively simple competition algorithms were capable of accounting for the majority of the competition response. Increasing model complexity did not appear to dramatically improve model accuracy. Comparison of specific competition processes, such as radiation interception, was very difficult since the effects of these processes within each model could not be isolated. Algorithms for competition processes need to be modularised in such a way that exchange, evaluation and comparison across models is facilitated.     

建筑回填土中再生水灌溉对草坪草生长及土壤理化性质的影响

为探明建筑回填土条件下草坪草种植的适宜性以及再生水灌溉对草坪草生长和土壤理化性质的影响情况,选用黑麦草为试验对象,通过室内盆栽试验的方式,设置清水灌溉、再生水灌溉、清水—再生水交替灌溉3个处理,研究了呼和浩特市建筑回填土灌溉再生水对草坪草生长及土壤理化性质的影响。试验发现:(1)与清水灌溉相比,清水—再生水交替灌溉、再生水灌溉下的草坪草生长速率分别增长了23%,34%。(2)各处理草坪草在质地、盖度、均一性方面的得分表现为:再生水灌溉清水-再生水交替灌溉清水灌溉,但差异性不显著(P0.05)。(3)到观测结束期时,再生水、清水—再生水交替灌溉下的土壤全盐量较对照组分别增加了8%,3%。(4)不同灌溉水质条件下黑麦草对土壤重金属的富集具有差异性,土壤中重金属含量有增有减。试验结果表明,再生水灌溉对草坪草的生长速率有很明显的促进作用,草坪草的颜色在再生水灌溉下要显著优于其他处理(P0.05)。同时,对试验土壤及草坪草的后期分析能够发现,短期内再生水灌溉下的土壤不会对草坪草产生盐害,土壤也均未受到污染,可见短期内建筑回填土下使用再生水灌溉草坪草是可行的。     

贵草1号多花黑麦草区域试验

2001-2004年在贵州海拔650～2220m不同区域对贵草1号多花黑麦草的植物学性状、生物学特性、生产性能、抗逆性等进行了3年的综合评比观测,测定结果表明:贵草1号多花黑麦草新品系在4个试点种植均表现较强的适应性.从播种到种子成熟需要234～239d,生育期内生长旺盛,无严重病虫害发生;鲜草产量平均为4 963.6kg/667m2,比对照增产17.8%.     

进境苇状羊茅和多年生黑麦草种子携带内生真菌带菌率的研究

苇状羊茅内生真菌和多年生黑麦草内生真菌曾给一些国家的畜牧业造成巨大损失.为防止内生真菌随进境草籽传入我国并在中国扩散危害,我们对该2种进境草籽内生真菌的带菌率进行了研究.首先通过分离培养,得到了苇状羊茅内生真菌和黑麦草内生真菌,然后采用染色法对1998年以来收集到的从天津口岸进境的部分苇状羊茅和黑麦草种子进行了初步检验,经检验,37份苇状羊茅样品中有18个品种带菌,34份多年生黑麦草样品中14个品种带菌,带菌率最高可达86.7%.早熟禾、剪股颖等其它禾本科草籽目前尚未发现带有内生真菌.