莲藕施肥机无轴双螺旋供肥装置性能分析与试验

针对藕田施肥过程中存在的劳动强度高、施肥稳定性及均匀性较低的问题,设计了一种水力喷射式莲藕施肥机,其主要分为供肥装置和水肥混合装置,主要对无轴双螺旋供肥装置进行了设计与分析。通过理论分析确定影响供肥性能参数主要为螺旋转速、直径和导程,结合藕田施肥农艺要求确定上述3项参数的取值范围。利用EDEM对无轴双螺旋供肥性能进行离散元仿真分析,以供肥量均值和供肥量稳定性变异系数为评价指标分别进行单因素试验和回归正交旋转组合试验。单因素试验结果表明：供肥量均值随着螺旋转速、直径和导程的增大而增大,并且具有良好的线性关系,因此可通过调节供肥螺旋转速、直径和导程来改变供肥量均值;供肥量稳定性变异系数随着螺旋转速和导程的增大呈现先降低后升高的趋势,而随着直径的增大而减小。运用Design-Expert软件对回归正交旋转组合试验结果进行分析优化,分别开展仿真试验和台架试验对优化后的参数进行验证。结果表明,当螺旋转速为160 r·min^-1,螺旋直径为78 mm,螺旋导程为53 mm时,仿真结果供肥量均值为329.43 g·s^-1,供肥量稳定性变异系数为1.43%,...     

香荚兰镰刀菌根腐病药剂毒力测定及幼根接种防治试验

在ＰＤＡ含毒介质上的试验表明,苯莱特（５０％ＷＰ）、多菌灵（５０％ＷＰ）、甲基托布津（７０％ＷＰ）抑菌效果最好,稀释３０万倍的药液对尖孢镰刀菌抑菌率分别为１００％、９１．９％、６７．９％,而粉锈灵（１５％ＷＰ）３０００倍液,抑菌率仅为７０．１％;苯莱特、粉锈灵１５００倍液对腐皮镰刀菌抑菌率仅为９４．４％和１４．０％。苯莱特和粉锈灵对尖孢镰刀菌的抑菌效果明显高于腐皮镰刀菌。抑菌圈法试验,多菌灵、苯莱特５００～１０００倍液对腐皮菌的防效又优于尖孢镰刀菌,而粉锈灵对２种镰刀菌均不产生抑菌圈。香荚兰幼根接种药效试验,粉锈灵对尖孢镰刀菌防效最好（５６．６％）,多菌灵、甲基托布津次之（５１．６％、５０．９％）,而苯莱特较差（４０．４％）。粉锈灵１０００倍液浸泡１ｈ和盆栽施药,均对香荚兰幼根产生药害。     

西双版纳香荚兰根腐病发病规律研究

通过系统观察,香荚兰根腐病周年发生,随种植时间延长而病情累积增高。新增病根发病率增高在高温季节,而在低温干旱季节降低。根腐病发病率＜５０％的调查样方有１９．７％的表现出蔓叶发黄;发病率＞６０％的,则有９０％以上的蔓叶发黄,可以把发病率＜４０％作为该病的控制指标。田间管理好,根系发达,生长良好的园地,病情较轻。离体幼根接种试验表明,根尖和根毛区是病原主要的入侵部位。有１５％的幼根不感病,大多数感病根,病斑扩展到一定程度即停止活动,仅有１２％的根病斑发展到全根死亡。病斑扩展期为２～７ｄ,扩展速度为０．２～８．４ｍｍ／ｄ。     

深耘断根对旱地高产小麦花后根系干重及产量的影响

在旱地大田条件下研究了深耘断根对旱地高产小麦花后根系干重及产量的影响,结果表明,４个处理中以冬前深耘断根最好,起身期深耘断根与对照（不断根）次之,冬前和起身期都深耘断根效果最差,冬前深耘断根可增加中,下层和根系的重量和比率,降低根系生长冗余性,控制最高总茎数,提高成穗数及成穗率,使子粒产量中各自花后光合率官输送的比例增加,从而使产量提高,因而在旱地高产麦田应推广冬前深耘断根。     

Rooting ability of Leucaena leucocephala stem cuttings

Single-node leafy and leafless cuttings harvested from one-year-old, 1.3 to 1.5 m tall Leucaena leucocephala seedlings were successfully rooted in a non-mist propagator which is suitable for use in the rural tropics. Cuttings with a leaf attached rooted more successfully than those without a leaf (71% and 39% respectively) and clones differed significantly (43% to 71%). There was also a clear pattern in rooting ability of cuttings collected sequentially down the main stem. Cuttings rooted most successfully when taken from node five to 13, counting from the apex; this was the region where internodes were longest (64 to 109 mm) of moderate diameter (2.9 to 5.5 mm) and all cuttings had a leaf attached. This revised version was published online in June 2006 with corrections to the Cover Date.     

桑叶菊花保健饮料

以桑叶和菊花为主要原料,研制出色、香、味俱佳的保健饮料。对桑叶和菊花提取液的褐变和护色进行了较详细研究,并确定柠檬酸为护色剂,有效地防止了桑叶和菊花提取液的褐变。     

Distribution of ectomycorrhizas and ectomycorrhizal fungal inoculum with soil depth in a birch forest

The distributions of ectomycorrhizas and ectomycorrhizal fungal inoculum with soil depth (0–45 cm) were determined in a 40-year-oldBetula platyphylla var.japonica forest. Mycorrhizal and non-mycorrhizal fine roots were measured in each soil core sample that was collected at soil depths of 0–5, 5–10, 10–15, 15–20, 20–25, 30–35, and 40–45 cm. The ectomycorrhizas were mainly distributed (>50%) in the top soil (0–5 cm) of organic forest floor horizons. Below 5 cm the quantity of ectomycorrhizas decreased sharply. The percentage of fine roots which were ectomycorrhizal gradually declined with the depth of soil. The ectomycorrhizal fungal inoculum was evaluated by a bioassay method, measuring the lengths of the entire root system and of the ectomycorrhizal roots of birch seedlings planted in each soil sample. The soil samples were collected from 0–5, 10–15, 20–25, 30–35, and 40–45 cm depths of the soil profile. Ectomycorrhizal formation on birch seedling roots in the bioassay was high in both the soil depth intervals 0–5 cm and 10–15 cm, while the amount was lower in the soil depth interval from 20–45 cm. The results of these investigations show that the amount of the ectomycorrhizas in soil, and the ectomycorrhizal fungal inoculum potential as determined by bioassay, are not always consistent with each other.     

Field performance of containerized black spruce seedlings with root systems damaged by freezing or pruning

Roots of 2-year-old black spruce seedlings (Picea mariana [Mill.] B.S.P.) were exposed to freezing temperatures to destroy 20, 40, 60, and 80% of the root systems. For comparison, other root systems were pruned to eliminate the same proportions of roots. Treated and control seedlings were planted in spring 1992 at Forêt Montmorency (the Université Laval forest research station, 50 km north of Quebec City). From 1992 to 1995, survival, shoot height and stem diameter were measured. Mortality mainly occurred in 1993, the year after planting; pruned seedlings showed practically no mortality while seedlings with 20, 40, 60, and 80% of their root systems affected by frost showed mortality rates of 0, 6, 17, and 24%, respectively. Shoot height and stem diameter decreased with increasing root damage when compared to controls. After three years on the planting site, shoot height was reduced by 2, 8, 11, and 18% while stem diameter was reduced by 4, 21, 25, and 24% for 20, 40, 60, and 80% frost damage, respectively. For pruned seedlings, shoot height was increased by 3% at 20% damage and was decreased by 1, 3, and 13% for 40, 60, and 80% root damage while stem diameter was reduced by 1, 4, 8, 19% for 20, 40, 60, and 80% respectively. Use of damaged seedlings on the planting sites should be limited in order to reduce the cost of replacement planting.     

温度周年变化与桑树植原体消长的关系

通过聚合酶链反应检测了植原体在桑树体内的分布及其相对含量的周年变化。结果显示,茎部中植原体的含量在生长季节逐渐升高,７月达到最大,而冬季检测不到,叶部与茎部相似但植原体的含量在８月达到最大;根部全年均含有植原体,含量较低。     

Analysis of genetic variability of aluminium tolerance response in triticale

Comparative analyses of genetic variability of aluminium tolerance response were made in a range of triticale genotypes of two sets, one consisting of six Australian cultivars (or lines), the other consisting of eight South African lines and an Australian check, by following solution culture and screening under controlled growth cabinet conditions. Results showed that Tahara, Tahara ‘S’ and Abacus were the most Al-tolerant triticales among the Australian genotypes in terms of root regrowth characteristics at 10 μg.g^-1 Al. The 19th ITSN 70-4, along with the standard cultivar Tahara was superior to all other South African genotypes; the eight South African genotypes spanned the range from Al-tolerant, moderately Al-tolerant to Al-sensitive. Regrown root length and percentage of seedlings with root regrowth were the two key indicators for screening and evaluating Al tolerance response. Considerable genetic variability of tolerance to Al stress among the two sets of tested genotypes was revealed by the estimates of genetic parameters. High heritability values were recorded for those two indicators, with associated high levels of relative genetic advance (RGA). Further improvement of varietal tolerance to Al stress in triticale could be anticipated through selection and breeding. This revised version was published online in July 2006 with corrections to the Cover Date.