红叶石楠秋季扦插育苗试验

红叶石楠秋季扦插育苗试验结果表明,不同基质、不同生根剂浓度及浸泡时间对红叶石楠扦插生根率具有极显著影响。红叶石楠选用混合基质(黄心土∶粗河沙∶草木灰=1∶1∶1),萘乙酸(NAA)生根剂200 mg/kg浓度浸泡2 h的生根率最高,达96.2%,可在生产中推广应用。     

矿粒粒径对深海采矿扬矿泵磨损特性的影响

为研究矿粒粒径对深海采矿扬矿泵过流部件磨损特性的影响,采用DPM模型模拟泵内固液两相流动,并以基于流体动力学的Oka磨损模型仿真颗粒对过流部件的磨损,分析扬矿泵在不同矿粒粒径下的磨损规律.研究结果表明:随着矿粒粒径的增大,首级叶轮及次级叶轮的前后盖板磨损量分布逐渐均匀,前盖板磨损量的集中区域从出口压力面向叶轮中部及进口吸力面转移,后盖板磨损量集中分布区域从进口吸力面一侧向出口压力面一侧转移,叶片进口和出口的磨损面积均逐渐增大;首级空间导叶及次级空间导叶的叶片背面进口磨损面积逐渐增大,在轮毂出口处磨损区域向外逐渐偏移,且该位置磨损面积逐渐减小;当矿粒粒径从1.0 mm增大到5.0 mm时,首级叶轮和次级叶轮的前盖板最大磨损量分别上升132.9%和104.2%,首级叶轮和次级叶轮的叶片最大磨损量分别上升172.3%和142.5%,首级叶轮和次级叶轮的后盖板最大磨损量分别上升251.4%和102.3%,首级导叶和次级导叶的最大磨损量分别下降87.08%和74.26%.     

土壤—作物资源多目标优化配置分析

本文提出一种多目标土壤—作物资源优化配置的数量化分析方法,并对江苏省东海县土壤资源进行优化配置。结果表明：白浆土、岭砂土、包浆土、紫砂土等岗岭低产土应稳定小麦面积,压缩玉米面积,优先发展春花生、大豆、水稻;洼地砂姜黑土、水稻土应发展小麦—水稻和小麦—玉米两熟制,并适时换茬;介于上述两类土壤间的潮棕壤亚类和潮土类应大力发展小麦—花生两熟制。     

桑树树液蛋白质的双向电泳分析

应用 Ｉ Ｅ Ｆ 和 Ｓ Ｄ Ｓ Ｐ Ａ Ｇ Ｅ 双向电泳技术,分析了桑树（ Ｍｏｒｕｓ） 树液蛋白质的电泳图谱。结果表明,供试栽培品种的蛋白质谱比较相似,相似系数在０７２ ～１００ 之间;品种间存在１４ 个共有组分,占检测组分总数的５１９ ％ ;桑树栽培种与野生种的差异比较显著。     

一个山区农场生态农业系统的分析与评价

供试农场生态农业系统由加工业，牲猪，沼气池，桔园，鱼池和农田６个系统组成。本文运用“黑箱理论”和方法，对６个子系统的投入能量，产出能量，能量效益及投能结构进行了分析。全系统的能量产投科为０．８１，光能利用率为１．５５％，产品能与总投能之比为３７．８％，单位产值含能量为１８８．３ＧＪ／万元，系统投入的有机能占总投能的９５％。从系统的Ｎ素循环和动态平衡分析表明：农田，桔园的Ｎ素输入均大于输出，Ｎ素处于     

Population structure of poplar rust Melampsora larici-populina in the UK inferred from AFLP

AFLP profiles were generated from poplar leaf rust ( Melampsora larici-populina ) collected from Populus trichocarpa cv. Trichobel at six sites in the UK in 2001. Of a total of 145 isolates, 121 were unique AFLP phenotypes. On one occasion, the same AFLP phenotype was found at two sites. The analysis indicated that 81·88% of the total variation was attributable to differences among individuals within replicate plots, 3·47% to differences among plots within sites and 14·65% to differences among sites. Weir & Cockerham's θ was calculated as 0·138 and θ ^B , the Bayesian analogue of F _ST, as 0·146. Overall, there was sufficient gene flow among different sites to prevent genetic drift, as Nm was calculated as 1·562 using θ and as 1·462 using θ ^B . Nei's genetic distance and population-assignment test indicated that the rust from a site in north-east England was differentiated from those from other sites. There was no significant correlation between genetic and geographical distances. The results indicate that sexual reproduction has a major influence on the relative lack of population structure of M. larici-populina in the UK.     

不同肥料配方对番茄复合基质育苗的影响

本文以复合基质育苗的无土栽培方式为研究内容,在大棚温室条件下,通过在含有不同肥料配方的育苗基质（草炭：蛭石=2：1）中,进行番茄穴盘育苗。试验中分成4个处理,其中包括3个不同肥料配方和空白对照,每个处理分3次重复,最后测定番茄幼苗的各项生长指标。试验结果表明：在含有肥料配方2的基质中幼苗的株高、茎粗、干物重3项指标明显优于其它3个处理,肥料配方1的叶展指标最好,还有3项指标：株高、茎粗、干物重和肥料配方2无显著差异。处理3中含有的肥料配方3对番茄幼苗的各项生长指标都有明显的抑制作用。从而得出,本试验条件下,肥料配方2是培育番茄穴盘苗的最佳肥料配方。     

辣椒秸秆复合基质对西瓜育苗质量的影响

为降低西瓜基质育苗生产成本,采用不同比例的辣椒秸秆与蛭石、珍珠岩进行复配,探讨其对西瓜幼苗形态建成及生理特性的影响,以明确最佳的草炭替代材料.试验设置L1(V辣椒秸秆:V蛭石:V珍珠岩=1:1:1)、L2(V辣椒秸秆:V蛭石:V珍珠岩=2:1:1)、L3(V辣椒秸秆:V蛭石:V珍珠岩=4:1:1)3个处理和对照CK(V...     

Sap flow in ‘Hass’ avocado trees on two clonal rootstocks in relation to xylem anatomy

The rates of sap flow and xylem vessel features were studied in two-year-old nongrafted and grafted avocado (Persea americana Mill.) trees. Daily sap flow rates were measured with heat and balance stem gauges in clonal Duke 7 (D7) and Toro Canyon (TC) trees and ‘Hass’ clonal scions grafted onto clonal D7 (H/D7) and TC (H/TC) rootstocks. Vessel features as size, number and total vessel area were determined histologically in the stem of the scion and rootstock and the roots of the grafted trees. Significant differences in the sap flow rate were found among the rootstocks, where D7 had a 29% higher sap flow rate than did TC (grafted and nongrafted trees). There were no differences among xylem vessel features in the stems of any of the varieties. However in the roots, D7 had wider and fewer vessels then TC do. Also, D7 had a 19% higher total vessel area than TC. These results suggest that the differences in water consumption of ‘Hass’ on different rootstocks may be associated with differences in the efficiency of the roots to absorb water across conductive tissue which may be linked to differences in the area of xylem vessels in the root.