Hard clam relocation as a potential strategy for QPX disease mitigation within an enzootic estuary

Monitoring of persistent QPX infections in clams of Raritan Bay (New York) shows certain areas of the estuary have remained without any significant disease prevalence. This study was conducted to investigate the potential to mitigate QPX disease by relocating infected hard clams, Mercenaria mercenaria (Linnaeus), from enzootic areas to nearby sites with prevailing environmental conditions suggested to deter infection and favour remission and healing. Clams were collected from a location with consistent disease prevalence in central Raritan Bay and brought to near shore habitats subject to lower salinities and higher summer temperatures. A reduced host density treatment was included in the study to examine the common observation of high clam density in the most persistently infected locales. An additional treatment retained clams above the sediment, since sediments are suspected to represent a QPX reservoir. At the end of the 4‐month study all treatments displayed less QPX disease than the control group and the greatest contrast was provided by the disappearance of infections in a tidal creek.     

不同播种量对甘肃礼县掌叶大黄育苗质量的影响

通过在甘肃礼县采收三年生掌叶大黄种株种子并采用不同播种量(35,45,55,65,75和85 kg/hm²)育苗,育苗结束后测定苗栽质量指标,移栽定植到大田后定期测定成活率,旨在揭示播种量对掌叶大黄苗栽质量的影响,为其规范化栽培提供依据。结果表明,在甘肃礼县育苗时种子播种量对掌叶大黄育苗质量具有极显著影响,在35 kg/hm²最低播种量基础上,随着播种量的增大育成苗栽数持续增多,苗栽产量先显著提高后下降,但苗栽根长、根粗、单苗重和根系TTC还原强度等个体质量指标均呈降低趋势,播种量为65 kg/hm²时苗栽产量最高,单苗鲜重和根系TTC还原强度减小程度较轻,苗栽综合指标优异,生长健壮,大小适中,产苗数多,移栽成活率高,说明从育苗质量和育苗效益综合考虑,甘肃礼县掌叶大黄育苗适宜种子播种量为65 kg/hm²。     

机插稻高产栽培技术

主要介绍新型机插稻的播前准备、机插秧苗的技术要求以及后期的秧田管理技术,以此来为进一步推广机插水稻的提供科学依据。     

暗紫贝母的繁殖器官在海拔梯度上的变异

在青藏高原东部的一个高山坡面上,沿着海拔设置高、中、低3个海拔部位,并在高、低海拔之间进行暗紫贝母植株的对换移植实验,然后测定各部位的生态因子、暗紫贝母植株花、果实和种子的特征。结果表明,1)生态因子中积雪融化时间、气温及土壤含水量在各海拔之间有明显的差异;2)花部特征中花被片的长度和宽度,雄蕊花药和花丝的长度,花柱和柱头裂片的长度都是高海拔部位最长,低海拔部位最短;3)对花生物量来说,高海拔部位比低海拔部位大39.4%;从花与地上部分二者生物量的比率来看,高海拔部位比低海拔部位大12.3%,两个指标都是高海拔部位排名第一;4)单粒果实重以低海拔部位最重,达到1282 mg,比高海拔部位大48.3%;5)单粒果实种子数以高海拔部位最少,比低海拔部位少了38.1%;6)高海拔部位的种子百粒重达到142.3 mg,而低海拔部位种子百粒重只有94.6 mg。移植实验进一步验证了上述的测定结果,这说明暗紫贝母繁殖器官确实要受海拔的影响,而且主要跟海拔梯度上的融雪时间、气温(尤其是零下低温)、紫外线强度、访花昆虫等有关。     

应用简易移植盒进行红松异砧嫁接造林研究

[目的]提高立地条件较差林地的红松异砧嫁接造林的成活率。[方法]采用木材加工的边角余料订制简易移植盒进行造林。[结果]采用简易移植盒进行造林可以大大提高在干旱、半干旱黄色沙壤土条件下的造林成活率,并保证了第二年的保存率。[结论]应用简易移植盒可以有效提高造林成活率。     

不同育苗基质对玉米幼苗素质的影响

为增加玉米生长积温,提高保苗率,以充分利用农业废弃物。根据各地育苗基质来源不同,以牛粪、草炭和稻壳灰为主要原料,按照一定比例与土壤配比,进行不同配比基质筛选。结果表明:处理2以牛粪20%、草炭30%、稻壳灰20%和土壤30%作为育苗基质,对玉米幼苗素质影响最好,其幼苗叶绿素含量和根系生长量等各项指标均好于其它基质处理,处理1和处理3之间育苗效果差别不明显,但不如对照处理。说明以农业废弃物作为育苗基质,可部分或全部代替土壤育苗,还可对农业废弃物进行循环利用。     

珍稀濒危莲瓣兰组织培养试管苗移栽的研究

以莲瓣兰‘苍江大雪素’组织培养生根试管苗为试材,研究移栽基质、移栽时间、试管苗大小对莲瓣兰试管苗移栽的影响。结果表明:在大理3月和9月份莲瓣兰试管苗移栽成活率最高,二者无显著差异,3月份移栽根系生长显著优于9月份,是一年中移栽的最佳时期;栗树叶作为移栽基质莲瓣兰试管苗移栽成活率和生根显著优于水苔、珍珠岩、红仙土和碎树皮,水苔、珍珠岩和红仙土不宜作为莲瓣兰试管苗的移栽基质;莲瓣兰试管苗大小对移栽成活率及生根影响较大,中苗移栽成活率显著优于大苗和小苗,大苗移栽生根优于中苗,小苗移栽难生根。     

闭锁室内水分、养分及光照强度对番茄幼苗生长的影响

以中杂9号番茄为供试品种,采用72孔穴盘,在闭锁型育苗系统内进行番茄穴盘育苗的不同水分、养分及光照强度试验,测定番茄幼苗叶片数、株高、茎粗、地上部和地下部干质量、根冠比、壮苗指数、叶绿素含量等指标。结果表明,闭锁型育苗系统内基质相对含水量为70%～80%、每2d每盘浇灌1次1倍山崎配方营养液500mL和光照强度为320μmol.m-2.s-1时,幼苗生长明显好于其他处理。     

钻天柳繁育技术研究

经过多年的研究，总结出了钻天柳种子收集、贮存、播种、扦插、移栽等技术措施。钻天柳适宜采种期为7月末8月初，种子千粒重0．303g，秋播时间在8月10日以前。当年不播的种子可用快速封闭法贮存，春播时间在5月10日前后。播种量1．25g/m^2。扦插时间在7月10日前后，插穗用200mg/kg1号生根粉处理3h左右，扦插密度480株/m^2。移栽时坐平、平茬，成活率可达90％以上，第2年进入速生期。     

Transplant Stress Index: A proposed method of quantifying planting check

This paper demonstrates a simple way of estimating the intensity and duration of planting check by examining height growth patterns. A transplant stress index is determined by the relationship between initial seedling height and subsequent height growth. This index is defined as the slope of a linear relationship between initial height and height increment. If the slope is negative, the plants (as a population) are said to be experiencing planting check. When the slope is approximately zero, the stock is said to be recovering from planting check. A steep positive slope suggests the stock has recovered from planting check. TSI values were determined for several conifers including Pinus elliottii Engelm. var. elliottii, Pinus taeda L., Pinus radiata D. Don, Picea sitchensis (Bongard) Carrière, and Larix× eurolepis Henry.