Dynamic emulation of the effect from a single tree to lower solar radiation distribution

By modeling the condition of light climate, we studied the negative effect of shadows in a shelterbelt forest. Based on the calculation of the apparent trajectory of solar motion according to an ellipsoid crown projection model and a Monsi light transmission model, radiation values of 36 experimental sites were measured using a light quantum meter. Estimates of daily solar radiation distribution from measured values were obtained. We built a crown projection model and simulated the conditions of a light climate in the forest. The trajectory of the shadow motion is shaped like a butterfly arc. The situation of the outside is affected by tree height (H) and that of the inner arc by height below the branches. In an area of 1.0 × H (toward the east and west of the tree) and 0.6 × H (toward the north), transmittance was below 90%, which means that the effect of shadow hazards occurs in this area. As well, the effect was strong at the bottom of the tree. The area of shadow hazards in the east and west of the tree was large and small in the south. The projection area of the shelterbelt forest was largest along an east and west direction. A certain distance between crops and the shelterbelt should be maintained when the shelterbelt is in a north-south direction. Therefore, the effect of shadow hazard will decrease north of the tropic of cancer. Cutting out the lower branches from the trees of the existing shelterbelt in a suitable and timely manner can reduce the area of the shadows. __________ Translated from Journal of Northwest A&F University, 2008, 36(6): 113–118 [译自: 西北农林科技大学学报]     

Identification of the spontaneous 7BS/7RL intergenomic translocation in one F1 multigeneric hybrid from the Triticeae tribe

The F1 AABBRH^ch hybrids studied here were produced by crosses between the Portuguese triticale cultivar 'Douro' (AABBRR) and the tritordeum line HT9 (AABBH^chH^ch). Fluorescent in situ hybridization performed with genomic DNA probes genomic in situ hybridization (GISH) from rye and Hordeum chilense allowed the unequivocal parental genomes discrimination in all hybrids. Among 55 plants, one presented a spontaneous wheat–rye translocation which was successfully detected after GISH. Recombinant chromosomes identification was made after reprobe with pTa71 and pSc119.2. Nine rDNA loci were detected by pTa71 and pSc119.2 identified the chromosome arms involved in the translocation, after comparing the observed hybridization patterns with those described by several authors. We identified the spontaneous wheat–rye translocation as being the 7BS/7RL. Many wheat–rye translocations have been found (e.g. 1BL.1RS and 1AL.1RS), but as far as we know, this is the first time that this translocation is reported. We considered it helpful for wheat breeding programmes as it could provide the transference of interesting agronomic characteristics from rye (e.g. leaf rust resistance) to wheat.     

甘蓝自交不亲和基因MLPK与SSP的FISH定位

利用FISH技术, 对自交不亲和基因MLPK与SSP在甘蓝有丝分裂前中期染色体、减数分裂早粗线期染色体以及伸长DNA纤维等3种分辨率水平的靶DNA载体上进行物理定位。结果表明, 在有丝分裂前中期, MLPK探针信号位于一对近中着丝粒同源染色体的短臂中部, 距着丝粒的百分距离约为53.41±3.16;SSP探针信号位于一对具有随体的近端着丝粒同源染色体的长臂端部, 距着丝粒的百分距离约为78.36±4.26。综合3种载体上的FISH结果表明, MLPK与SSP在甘蓝染色体组中可能都只有一个同源序列座位, 具有在单倍体基因组中的单拷贝性。重复FISH杂交表明, MLPK与5S rDNA位于同一对染色体。依据Armstrong的核型分析标准, 初步判断MLPK与SSP分别位于甘蓝的2号和7号染色体, 与S位点不存在连锁关系。另从比较基因组学角度对定位结果进行了讨论。     

我国水排污权交易制度分析

人类活动逐渐成为环境恶化的最主要原因,大量污水的排放得不到有效控制和治理导致目前我国的流域水污染更趋严重.分析了我国建立水排污权交易制度的必要性、可行性及其在实践中存在的问题,以期完善水排污权交易制度,有效防治水污染.     

湖库型饮用水水源地污染防治对策研究

目前我国湖库型饮用水水源地水质总体状况较好,但不同程度地存在一些污染,分析其污染的原因,主要表现在工业废水和生活污水点源污染的排放,农田种植业、养殖业等引起的面源污染以及相关管理措施欠完善.根据湖库型饮用水水源地污染现状及危害,结合国内外湖库型饮用水水源地污染防治对策,综述了常用保护措施,为湖库型饮用水水源地保护提供依据.     

隆德县玉米全膜覆盖沟播栽培技术

全膜覆盖能最大限度的保蓄玉米生长期间的全部降雨,使降水利用率达到90%左右。从选茬整地、科学施肥、规格起垄、覆膜播种、田间管理等方面介绍了隆德干旱区旱地玉米全膜覆盖沟播栽培技术,为隆德县玉米高产优质提供了有力的技术支撑。     

陇东黄土高原旱作区土壤水分变化规律及其与玉米产量关系探讨

利用西峰农业气象试验站玉米观测地段土壤水分资料（1990~2007年）和玉米产量资料,以及与之毗邻的西峰基准站气象资料,分析了观测地段土壤水分变化规律及土壤水分变化对玉米产量的影响。结果显示：土壤贮水量的变化呈二次曲线,贮水量最低值出现在8月中旬;耗水量的变化呈直线;贮水量与玉米产量相关最显著的时段在拔节到抽雄阶段,拔节～抽雄0～50cm土壤贮水量每增加10mm,产量增加180-210kg/hm2.     

不同施氯水平对云南烤烟生长、产量和品质的影响

采用田间小区试验研究了不同施氯水平对云南烤烟生长、产量和品质的影响。结果表明,施氯水平与烟叶氯含量呈显著正相关（P<0.05）,而与K2O/Cl比值呈显著负相关（P<0.05）。在本试验条件下,在0~112.50kg/hm2的施氯水平范围内,施氯对烟叶具有增产、增加产值和提高中上等烟比例的效应。烤烟产量、产值和中上等烟比例以67.50 kg/hm2的施氯水平为最高,其产值与CK间的差异达到显著水平（P<0.05）;烟叶化学成分含量以施氯水平为22.50kg/hm2时最接近优质烟叶的含量范围且各化学成分协调性较好。因此,从烤烟农艺性状、经济性状和品质综合考虑,云南省优质烤烟合理的施氯水平为22.50~67.50kg/hm2。     

插秧密度对寒地粳稻的产量及产量构成因素的影响

以松粳6号和超级稻松粳9号两个寒地粳稻品种为试验材料,研究了不同插秧密度对寒地粳稻产量及产量构成因素的影响.结果表明,不同插秧密度对两品种千粒重影响相对较小,而对每穴穗数和每穗粒数的影响相对较大.在黑龙江省第一积温带地区,松粳6号和超级稻松粳9号的最适插秧行株距为30cm×13.3cm和30cm×16.7cm.     

气候变化对福州植物气候生产力的影响分析

利用Thornthwaite Memoriae模型估算了福州市近30多年来的植物气候生产力的状况,在分析了年均气温、降水量、风速和相对湿度年际变化的基础上,探讨了植物气候生产力的变化原因。植物气候生产力与年均气温、风速成正比,故20世纪70年代后期和90年代后,受其影响,植物气候生产力在增大;植物气候生产力与年降水量和相对湿度成反比,所以20世纪70年代前期以及80年代,植物气候生产力在逐渐降低。