基于未确知有理数理论的农村新民居设计方案评选

以未确知有理数理论为基础,给出了评价农村新民居住宅设计方案优劣的一种数学模型方法,并将该方法模型用于指导农村新民居示范村建设。     

型如a^n-1或a^n＋1（n∈N＋）的标准分解式

探讨常见的型如a^n-1或a^n＋1（h∈N＋）的标准分解式．利用算术基本定理，对整数进行分解质因数是解决初等数论问题的重要途径．分解质因数的最基本方法是查质数表，但对于型如a^n-1或a^n＋1（n∈N＋）的数一般较大，要按此方法将其写成标准分解式并非易事，我们可以通过利用欧拉定理及同余性质探讨对这类数进行分解质因数的捷径．通过探讨研究得出解决此类数的标准分解式的两个定理，并推导型如2^n-1，2^2n＋1，2^3k＋1等特殊类型数的质因数的问题．利用得出的定理和推论对解决初等数论中的相关问题有着一定的意义．     

饲用甜菜染色体倍性与叶片气孔性状相关性研究

以饲用甜菜二倍体和四倍体为试验材料,研究了气孔的长、宽度及气孔保卫细胞叶绿体数目与倍性的关系.结果表明:二倍体植株与四倍体植株的气孔长、宽度和保卫细胞叶绿体数之间差异显著.四倍体气孔长度约为二倍体的1.8倍,宽度约为二倍体的1.42倍;且相对于气孔宽度,气孔长度具有更好的可靠性和区分效果;二倍体植株与四倍体植株的保卫细胞叶绿体数的平均值分别为13.69和23.24,可将保卫细胞气孔长度与保卫细胞叶绿体数两个气孔性状相结合,作为饲用甜菜多倍体育种初期的筛选鉴定指标.     

Field-based evaluation of vernalization requirement,photoperiod response and earliness per se in bread wheat (Triticum aestivum L.)

Vernalization requirement, photoperiod response and earliness per se (EPS) of bread wheat cultivars are often determined using controlled environments. However, use of non-field conditions may reduce the applicability of results for predicting field performance as well as increase the cost of evaluations. This research was undertaken, therefore, to determine whether field experiments could replace controlled environment studies and provide accurate characterization of these three traits among winter wheat cultivars. Twenty-six cultivars were evaluated under field conditions using two natural photoperiod regimes (from different transplanting dates) and vernalization pre-treatments. Relative responses to vernalization (RRV_GDD) and photoperiod (RRP_GDD) were quantified using the reciprocal of thermal time to end of ear emergence, whereas earliness per se was estimated by calculating thermal time from seedling emergence until end of ear emergence for fully vernalized and lately planted material. An additional index based on final leaf numbers was also calculated to characterize response to vernalization (RRV_FLN). To test whether the obtained indices have predictive power, results were compared with cultivar parameters estimated for the CSM-Cropsim-CERES-Wheat model Version 4.0.2.0. For vernalization requirement, RRV_GDD was compared with the vernalization parameter P1V, for photoperiod (RRP_GDD), with P1D, and for earliness per se, EPS was compared with the sum of the component phase durations. Allowing for variation in EPS in the calibration improved the relation between observed versus simulated data substantially: correlations of RRP_GDD with P1D increased from r² = .34 (p < .01), to .82 (p < .001), and of RRV_GDD with P1V, from r² = .88 (p < .001), to .94 (p < .001). In comparisons of observed versus simulated anthesis dates for independent field experiments, the estimated model coefficients resulted in an r² of .98 (p < .001) and root mean square error of 1d. Overall, the results indicated that combining planting dates with vernalization pre-treatments can permit reliable, quantitative characterization of vernalization requirement, photoperiod response and EPS of wheat cultivars. Furthermore, emphasize the need for further study to clarify aspects that determine EPS, including whether measured EPS varies with temperature or other factors.     

Discovery of and Preliminary studies on a Rapid-Leafing Rice Genotype at the Vegetative Growth Stage

The leafing rates of fourteen rice varieties were measured in a sowing-time experiment, and a rapid leafing genotype at the vegetative growth stage was discovered in an indica variety Yanhui 559. The leaf number on the main culm of Yanhui 559 was always 4-5 leaves more than that of Lemont, and the leafing rate of Yanhui 559 was significantly higher than that of Lemont based on similar growth durations from sowing to heading. Furthermore, the difference of the leafing rate was significant at the vegetative growth stage, but not distinctive at the panicle initiation stage. Genetic analysis of the leafing rates in the two backcross populations of Yanhui 559 and Lemont showed that major and quantitative genes controlled the expression of rapid leafing character. Based on results of investigation for some plants with similar growth durations in the backcrossing populations, the rapid leafing genotypes exhibited earlier tillering and more tiller numbers per plant, and its yield components including the number of panicles per plant and number of grains per panicle were superior to those of the slow leafing genotypes. Further research and application feasibility of the rapid leafing genotype in breeding were discussed.     

秸秆覆盖与施磷对旱地小麦小花发育与结实特性的影响

中国西南丘陵旱地气候冬干春旱且速效磷缺乏,是冬小麦生产的主要限制因素。为明确秸秆覆盖与施磷对西南丘陵旱地小麦小花发育与结实特性的影响,以川麦104为供试材料,采用裂区设计,主区为玉米秸秆覆盖(SM)和不覆盖(NSM),裂区为0、75和120 kg P₂O₅·hm^-23个施磷水平,比较分析了不同处理下小麦小花分化及结实特性的差异。结果表明,秸秆覆盖与施磷均可提高小麦小花分化数和可孕小花数,且磷素效应大于秸秆覆盖效应。与不施磷相比,施磷75和120 kg·hm^-2条件下最大分化小花数分别增加了17.4%和78.0%,可孕小花数分别增加27.0%和94.1%,小花存活率提高了16.5个百分点。施磷后穗基部可孕小花数和结实粒数增幅较大,穗中部和顶部增幅较小。与不施磷相比,施磷75和120 kg·hm^-2条件下,穗基部可孕小花数均极显著增加,增幅分别为100.0%和127.2%;结实粒数显著增加,增幅分别为186.4%和193.2%。秸秆覆盖后产量较不覆盖提高20.5%;施磷75和120...     

Variability in Azolla sporulation in response to phosphorus application

 Phosphorus application decreased the sporulation frequency and number of sporocarps per plant in all the three Azolla species and 21 A. pinnata strains evaluated in this study. The number of megasporocarps tended to be more depressed than the number of microsporocarps. Nevertheless, the sporulation of A. caroliniana was less sensitive to P than that of A. pinnata and A. microphylla. Its sporulation frequency in the mineral medium did not decrease at 2.5 μg P ml^–1 and remained unaffected between 5 and 20 μg P ml^–1. The sporulation frequency and sporocarp number in this species in the soil culture also were not significantly affected by an increase in the dose of P from 10.7 to 21.4 or 21.4 to 32.1 mg pot^–1. Large variations in the degree of inhibition of sporulation due to the application of P (21.4 mg pot^–1) also occurred among the A. pinnata strains tested. Received: 20 October 1999     

A comparison of needle retention on Japanese black pine and Japanese red pine

Needle retention (number of needle sets), needle density, height increment and radial increment were surveyed on seven Japanese black pines (Pinus thunbergii Parl.) and seven Japanese red pines (Pinus densiflora Sieb. et Zucc.) growing on the same site. Number of needle sets on branches with respect to whorl position was estimated visually. In 1999, maximum summer needle retention was observed on the fifth and sixth whorl from the top, with values of 3.4 needle sets for the black pines and 2.4 needle sets for the red pines, respectively. The needle trace method (NTM) was used to determine needle retention and needle density along the main stems retrospectively for the years 1968–1998. The long-term mean summer needle retention along the main stem was 3.7 needle sets for the black pines and 2.2 needle sets for the red pines. In both pine species, the number of needle sets varied from year to year. However, the long-term budget between newly born and annually shed needle sets was in equilibrium. The long-term average of needle density per cm of stem shoot was 9.4 needle pairs for the black pines and 7.4 needle pairs for the red pines. The results showed clear intra-specific and inter-specific similarities in needle retention, height increment and radial increment trends. The values for number of needle sets, height increment and radial increment positively increased with favorable growing conditions, whereas the value of needle density had an opposite tendency.     

The successful transfer of primocane fruiting expression from raspberry to Rubus hybrid berry

This paper describes the successful transfer of the primocane fruiting (PF) character from raspberry (Rubus idaeus) to Rubus hybrid berries following crosses between raspberry and blackberry. The transfer was achieved by doubling the chromosome complement of PF raspberry selections in culture using colchicine, and using regenerant tetraploid PF plants as the female parents in crosses with tetraploid or octoploid blackberries, or with hexaploid hybrid berries (all summer fruiting). The results show that the PF character is expressed more readily in hybrid plants where at least 50% of the chromosomes in the hybrid genome are derived from raspberry. In vitro germination of cut seeds overcame the poor germination often encountered in Rubus and ensured the rapid recovery of hybrid seedlings. This revised version was published online in July 2006 with corrections to the Cover Date.     

大豆施用生物钾肥的土壤生物学效应

硅酸盐细菌有很强的解钾能力,同时还有解磷和固氮能力。将其菌剂与土壤混合制成每克干土含１０亿左右细胞的生物钾肥,用于大豆试验,结果表明生物钾肥可使土壤中有效氮、磷、钾含量提高,促进大豆植株对养分的吸收,使其干物质积累量增加,根瘤数量提高。