吊杯式移栽机作业时地表不平度的测量分析

为了研究吊杯式移栽机作业时所栽植土壤的地表不平度,采用超声波测距传感器,对吊杯式移栽机作业时的土壤表面不平度进行了测量分析。将超声波测距传感器垂直于地面安装到移栽机上,连续测量地表高低的变化,采用Lab VIEW编程控制超声波传感器的参数设定,由NI USB-6343 X系列数据采集卡采集数据,并可实时显示和存储在笔记本电脑上。计算分析所测数据,得出了试验田地土壤表面不平度的一些参数值,即地表不平度的RMS高度、轮廓微观不平度的平均间距和分形维数,为研究土壤特性对吊杯式移栽机性能的影响提供了一定的基础数据。     

不同生育期水分亏缺对烤烟干物质积累与代谢酶活性的影响

为探讨烤烟大田不同生育期亏水胁迫与烤烟物质积累及生理代谢的关系,以烤烟‘粤烟98’为材料,采用温室盆栽的方法,研究烤烟伸根期、旺长期和成熟期亏水胁迫处理下烟株干物质积累和叶片碳氮代谢关键酶活性变化。结果表明,伸根期亏水对大田烟株中、后期干物质积累的抑制效应具有滞后性且不可逆转;旺长期亏水仅仅对烟株茎器官干物质积累显著抑制效应,但可逆转,且成熟期时叶片叶绿素含量和硝酸还原酶活性处于较高水平,而淀粉酶活性处于较低水平;成熟期亏水显著降低根、茎器官及整株干物质积累,但对叶器官的干物质积累无显著影响。生产实践中,应高度重视伸根期和成熟期水分管理,确保烟株此期不受干旱,而旺长期适度亏水可以提升成熟期的烟叶田间耐熟性。     

卷荚相思组培快繁技术研究

以卷荚相思优树的带芽茎为外植体,进行初代培养、继代苗增殖培养、生根培养和组培苗移栽等组培快繁技术研究,结果表明,外植体初代培养最合适流程为:树冠中上部穗条经70%酒精消毒处理40 s后,再用0.1%HgCl2溶液消毒处理8min,萌动率高达35.7%;继代培养的最佳培养基为:改良MS+6-BA 0.8 mg.L-1+IAA 0.5 mg.L-1+蔗糖30 g.L-1,增殖倍数最高达5.2倍;生根培养以继代芽苗长1.1~1.4 cm,1/2MS+IBA 1.5 mg.L-1+ABT1#0.2 mg.L-1+NAA0.2 mg.L-1+蔗糖30 g.L-1培养基最佳,生根率最高达97.8%;组培苗移栽的最佳基质为红心土+泥炭土(3∶1),成活率达90%。     

龙芽葱木的组织培养及快速繁殖的研究

以龙芽葱木的芽为外植体进行组织培养试验,经试验对比筛选出龙芽葱木的外植体适宜诱导培养基为MS+6-BA1.0 mg.L-1+NAA 0.1 mg.L-1+Vc 30 mg.L-1,继代茎芽分化培养基为MS+6-BA 1.0 mg.L-1+ZT 0.1 mg.L-1+Vc50 mg.L-1,生根培养基为1/2MS+NAA 0.5 mg.L-1,以蛭石+森林腐殖土(1∶1)为培养基质移栽效果好。     

小型蔬菜移栽机械手的设计与试验

为避免蔬菜人工移栽存在的株距、行距和深浅度不均等问题,根据国家标准GB/T 5262-2008及蔬菜移栽农艺要求,设计了一种能够与吊篮-鸭嘴式移栽机结合的移栽机械手。根据现有的蔬菜育苗钵盘外形尺寸及茄科蔬菜的育苗农艺要求,并结合吊篮-鸭嘴式移栽机的结构,确定了移栽机械手的设计方案,设计了移栽机械手的整体结构及尺寸,并对移栽机械手关键部件进行有限元分析。结果表明:机械手指最大变形量为0.106mm,所受最大应力为6 5.5 MPa;大臂最大变形量为4.7 1 4×1 0^-6mm,所受最大应力为0.0 2 1 MPa;小臂最大变形量为9.476×10^-6mm,所受最大应力为0.0 2 2 6 MPa。试验结果表明:所设计的小型蔬菜移栽机械手能够在一定程度上解放劳动力,降低温室大棚内蔬菜移栽工作的劳动强度,可为以后全自动蔬菜移栽机的发展提供数据与理论参考。     

Use of hydrogels in the planting of industrial wood plantations

The quantity of available water in soil is crucial for plant growth, especially after transplanting as this water will enable the growth of new roots to facilitate nutrient and water uptake. Water absorbed by a hydrogel (superabsorbent polymer) has the potential to reduce drought stress after planting and to improve seedling survival. This article provides an overview of the concepts of post-plant water stress, a review of trials that tested application of hydrogels to forest tree species, and discussion on probable reasons for failure or success in the use of hydrogels. Hydrogels applied in pot trials, under controlled conditions, tended to have a higher frequency of positive survival responses compared with field trials (14 studies of the 17 (82%) in pot trials vs 15 of the 25 (60%) in field trials). In field trials, the application of hydrogels at planting had no effect on survival in seven of the 25 (28%) trials and had a negative effect in three of the 25 (12%) field trials included in this review. In the trials showing a positive response a hydrogel and water application improved survival by 18% and across all trials by 8%. The efficiency of hydrogels was probably influenced by the (1) chemicals present in the soil, (2) hydrogel quantity applied, (3) type of polymer, (4) hydrogel particle size distribution, (5) soil texture, (6) physical restrictions to hydrogel expansion, (7) hydrophilic nature of hydrogels, (8) unsaturated hydraulic conductivity between the substrate and the hydrogel particles, (9) application method and (10) planting conditions and rewatering. Due to this complexity and interactions between these factors it is difficult to provide site-specific recommendations for successful application of hydrogels in a forestry field setting. In general, application of hydrogels has been found to be more beneficial in sand or clay soils and to be of limited benefit in loam soils. Use of a hydrogel is not a replacement for good silviculture and has limited use as insurance against short periods of low rainfall. All efforts should be made to plant when environmental conditions are favourable for tree growth (i.e. wet soil and high probability of rainfall).     

不同酸调节溶液pH对生菜漂浮幼苗根系形态及产量的影响(英文)

[目的]为了解在蔬菜漂浮育苗系统中,采用不同酸调节溶液pH是否会对蔬菜根系及其它生长指标产生不同影响。[方法]分别采用硝酸和硫酸调节生菜(Lactuca sativa)漂浮育苗系统中不同营养液浓度下的溶液pH,观察两种酸对生菜根系形态的影响。[结果]不同营养液浓度下,两种酸对根系的影响效果不同。硝酸处理下,随着营养液浓度的增加,生菜地上部、根部生物量都增加,当营养液EC达到1.0μs/cm时,生菜地上部、根部鲜重显著高于硫酸处理;硫酸处理下,当营养液EC达到0.8μs/cm时,生菜的总根长达到344.8 cm,根总表面积为40.9 cm2,投影面积为13.0 cm2,根体积为0.4 m3,显著高于硝酸处理下的相应根系形态指标。比较同一营养液浓度下两种酸的处理效果发现,硫酸处理增加生菜根冠比,促进总根长、根表面积等根系形态的生长;硝酸处理促进生菜地上部生长、促进侧根发育、提高移苗效率、移苗后利于实现高产。[结论]该研究为生菜等蔬菜漂浮育苗和集约化穴盘育苗营养调控技术奠定理论基础。     

Variability of duration of pre-anthesis phases as a strategy for increasing wheat grain yield

In wheat, stem elongation phase (SEP) duration is critical for grain number (GN) per unit of area determination, as it is the phase in which the spikes grow. Lengthening SEP, for instance by photoperiodic sensitivity, without altering the cycle to anthesis (AT) has been proposed as an alternative way to increase spike dry weight, and in turn GN. As most works supporting this idea have modified only SEP by artificial manipulation (e.g. photoperiod extensions), it is relevant to evaluate this hypothesis in populations segregating for this attribute in natural conditions. The aim of this work was to analyse the variability in SEP duration relative to AT in two F4 populations; in order to select contrasting phenotypes to evaluate the impact of this attribute on grain yield components and to analyse the selection response of this attribute. These segregating populations (Las Rosas INTA × Triguero 230 (A) and Klein Estrella × ProINTA B. Alazán (B)) were derived from parental lines with similar flowering time but different relative duration of their pre-anthesis phases. Two field experiments with previous vernalization treatment in cool chamber were carried out. In 2006, F4 populations were characterized and from one of them (population B, which presented higher variability) four groups were selected, which presented contrasting phenotypes in the attribute under study. Progenies of these groups (F5), together with remnant F4 full-sib of each one, were studied during 2007. Grain yield per plant was higher, due to GN increases, when duration of the SEP was lengthened. However, selection response to longer SEP with similar cycle to AT could not be found, possibly as the result of a high environmental influence on this attribute. The phenotypic variability evidenced in this attribute was not clearly associated with major adaptation genes evaluated (i.e. Ppd and/or Vrn), suggesting that other minor genes could be associated.     

潞西市菠萝蜜大树移植最佳时间初探

菠萝蜜是著名的热带果树,也是一种优良的园林绿化树种,被广泛运用于我国南方城市绿化中.但由于菠萝蜜大树移植较难成活,难于达到目前"大树进城,速成景观"的城市绿化要求.结合当前云南省潞西市正在开展的城市园林绿化建设,对潞西市菠萝蜜大树移植的最佳时间进行了探究,结果表明,菠萝蜜大树最佳移植时间为4~7月和11月,配合木箱包装移植技术成活率可达91.36%.     

樟子松切根育苗试验

对樟子松进行切根育苗试验,结果表明,机械切根苗苗木质量优于移植苗和留床苗。切根２０ｃｍ的苗高、地径分别比移植苗高９４ｃｍ和粗０２ｃｍ,大于１ｍｍ的侧根数量,平均比移植苗多１１８条,比留床苗多１０条。机械切根可使２年生樟子松产苗量,比人工移植提高２４２９％～３７１４％,每公顷增加收入１５２８５～３０１１１元。