共查询到20条相似文献，搜索用时 189 毫秒
1.
<正> 解除冬芽休眠所需要的低温时数和低温程度,品种间有所差异。因此,对温暖地带的鹿儿岛地区所栽培的四个品种,就冬芽解除休眠所需要的低温时数进行了调查,以推测这些品种是否适合寒冷地区或亚热带地区栽培。调查材料采用鹿儿岛蚕业试验场栽植的4至5年矮干桑,品种为一之濑、新一之 相似文献
2.
3.
柞树是放养柞蚕的重要饲料,为了充分有效的利用柞树林型,提高柞蚕茧产量,笔者对柞林资源的林型进行了调查。结果表明,黑龙江省放养柞蚕主要树种是蒙古柞,而蒙古柞林所处的立地条件及生长特点可分为3种林型,其中胡枝子-蒙古柞林、榛子-蒙古柞林是最佳的放养柞蚕林型地。1蒙古柞1.1形态特征蒙古柞幼树树皮呈暗灰褐色,成熟树树皮呈暗灰色。幼期枝条呈紫褐色,小枝呈栗褐色,枝有棱,枝表面无毛。叶子常集生于枝条顶端,叶柄略短;叶呈倒卵形和倒卵长形,叶尖呈钝形,叶幅前端较为宽大(4￣9cm),叶长度为5￣20cm;叶子侧脉7￣12对;叶表面呈绿色,叶背颜色… 相似文献
4.
辽宁省饲养柞蚕的树种调查 总被引：1，自引：1，他引：0
<正> 在进行蚕业资源调查过程中,对辽宁省饲养柞蚕的主要树种及分布作了初步的调查。现将14种柞树及两种蒿柳的识别特征、生态分布及养蚕价值等,简要介绍如下,为挖掘资源潜力,充分利用柞树养蚕等,提供依据;并供有关单位研究参考。 麻栎(Quercus acutissma Carr.)又称尖柞、尖枣子、尖叶柞(图1)。 相似文献
5.
6.
7.
柞场内的柞树修剪形式与柞树生长发育、柞叶产量、叶质优劣、调节气候、防治病虫害、放养管理、人力节省等都有密切的关系。根据蚕儿生活阶段的气候环境及蚕儿生理需要来修剪柞树,是促使蚕儿发育健壮,柞树生长旺盛、保证柞茧丰收的主要关键之一。柞树的剪定形式在山东有中刈柞和根刈柞两种, 相似文献
8.
通过对河南省柞园柞树树型种类调查和对柞园的轮茬修剪、不同修剪方法养蚕的对比试验,探讨适合技术操作和放养柞蚕的理想树型,为河南省柞园的科学修剪提供理论依据。 相似文献
9.
<正> 柞蚕以柞叶为食,故柞场是放蚕的基础。山东省一些蚕区历来的习惯是春蚕用老柞(二年生柞),秋蚕用芽柞(一年生柞)。但因春季干旱少雨,柞树叶质衰老硬化快,蚕、柞不相适应。如何改造老柞,使之符合蚕儿生长发育的要求,这历来是春蚕饲料调节需要探索的问题。曾采用三眠柞、二芽柞和老眠柞等修剪形式,来控制春蚕用柞的老嫩和含水量的高低,对调节春蚕饲料起到一定的作用。但是这几种修剪形式都是用截短枝条的方法(只是位置轻重不同),更替顶芽生长,推迟发芽期,其结果缩小了树冠,影响了光能的充分利用,对柞树长势挫 相似文献
10.
柞树枝干害虫有的蛀食柞树枝干及根部,有的吮吸柞叶或嫩枝汁液,严重影响柞树的正常发育,降低柞叶的质量和产量,影响柞蚕生产。橡实害虫主要危害柞树橡实,使被危害的橡实不能发芽。下面介绍柞树主要的枝干害虫与橡实害虫及其防治方法。 相似文献
11.
12.
13.
槲树DNA SSR-PCR反应体系的正交优化 总被引：1，自引：0，他引：1
利用正交设计L16(45)对槲树(Quercus dentata Thunb.)基因组DNASSR-PCR反应体系的5个因素(Tap酶,Mg2+,,模板DNA,dNTP,引物)在4个水平上进行优化试验,筛选出各反应因素的最佳水平,建立了槲树模板DNASSR-PCR反应的最佳体系(20μL):60ng模板DNA,2mmol/LMg2+,0.075U/μLTaq酶,0.4mmol/L dNTP,引物浓度0.1μmol/L。对槲树DNASSR-PCR最佳反应体系的退火温度进行了梯度试验,最佳退火温度为51.3℃。 相似文献
14.
关于栎属(Quercus)植物柞树在植物分类阶元"科"的中文名称,有的文献称之为山毛榉科(Fagaceae),有的称之为壳斗科(Fagaceae);"科"所辖"属"的种类以及栎属的分组、柞树树种的中文名称也不尽相同。对上述分类阶元名称及栎属分组的考证结果认为:柞树在植物分类阶元"科"上的中文名称宜统称为壳斗科,柞树的"种"名应统一称为"栎";壳斗科在中国分布有7个属;青冈类植物应归为栎属的一个亚属———青冈亚属。 相似文献
15.
《Strength and Conditioning Journal》2008,61(3):294-301
Despite the increasing use of fire in managing oak woodlands, little information exists on quantitative changes to stand structure from prescribed burning. Fire damage and recovery in a mixed deciduous oak woodland were recorded after a prescribed fire on the northern Diablo Range, Santa Clara County, California. Blue oak (Quercus douglasii Hook. & Arn.), valley oak (Q. lobata Nee), and black oak (Q. kelloggii Newb.) trees were monitored for 4 yr to determine the effects of a late spring burn on stand structural characteristics. Fire-caused mortality was low; 4 yr after the low intensity ground fire only four oaks died (1.9%). There were significant differences in mean percent tree crown scorch and mean trunk char height between plots that burned under different fire intensities, but not between tree size classes. Although overall tree damage was low, crown resprouts developed on 80% of the trees and were found as shortly as 2 wk after the fire. Recovery was vigorous; both valley oaks and blue oaks produced crown resprouts on trees with 100% crown scorch. Classification tree analysis identified aspect (mostly southern exposures) and tree size related to the presence of crown resprouting. Crown damage was also an important factor; trees with greater than 40% of their crown scorched resprouted. Fire-induced trunk scars occurred on a small number of trees (9.1%) but was disproportionately higher for black oak compared to blue and valley oak. Stand structural characteristics (species composition, tree density, basal area, and crown closure) were not substantially altered by the event but rather maintained. Prescribed fire might be a viable tool in reducing fuels and maintaining oak woodlands; however, further investigations that include relationships of regeneration with repeated fire are needed. 相似文献
16.
Mekala SUNDARAM Ashley E. HIGDON Karl V. WOOD Connie C. BONHAM Robert K. SWIHART 《Integrative zoology》2020,15(2):89-102
The mechanism underlying detection of seed dormancy by scatter‐hoarding rodents is unclear, although previous work suggests that the pericarp plays an important role in signaling dormancy status. Eastern gray squirrels (Sciurus carolinensis) consume early germinating seeds as they are more likely to perish immediately, whereas dormant seeds tend to be cached. To examine the mechanisms underlying dormancy detection, we characterized physical and chemical differences between germinating and dormant pericarps of northern red oak (Quercus rubra), American chestnut (Castanea dentata) and the BC3 hybrid of Chinese chestnut and American chestnut (Castanea mollissima × C. dentata) using scanning electron microscopy and gas chromatography‐ mass spectrometry. We found that, as seeds break dormancy, the wax layer on the pericarp degrades and is accompanied by the escape of lower molecular weight kernel compounds or lipid metabolism byproducts. Our field experiments showed that squirrels were 4–8 times more likely to consume seeds that were altered to remove pericarp wax coating or that were sprayed with seed chemicals. We argue that dormancy detection by scatter‐hoarding rodents is a complex process involving physical cues such as loss of pericarp wax and chemical cues such as emission of olfactory cues. 相似文献
17.
对马蔺种子的发芽率及休眠原因进行分析研究,结果表明:马蔺种子在正常情况下很难发芽,存在休眠现象,属综合性休眠;磨破种皮、赤霉素浸种、浓硫酸浸种均能提高马蔺种子的发芽势、发芽率、发芽指数和活力指数。用浓度为75×10-6的赤霉素浸种能显著提高马蔺种子的发芽率。用浓硫酸浸泡马蔺种子,最适处理时间为1h,发芽率最高。 相似文献
18.
对柞蚕的蛹、卵、幼虫进行不同环境条件处理试验,调查柞蚕核型多角体病自然发病率。结果下列情况促使柞蚕发生较多的核型多角体病:暖茧期蚕蛹和孵卵期蚕卵长期接触高温多湿(27℃、90％)、低温多湿(15℃、90％);低温(7—8℃)抑制蚕卵胚子15天以上;春柞蚕卵在自然室温(13℃—19℃)保存30天以上;出蚕期卵层堆积厚度1.5cm以上;幼嫩饲料;“下河”蚁蚕的河滩畦芽育;五龄饷食蚕受到38℃3小时高温冲击。 相似文献
19.
《Strength and Conditioning Journal》2019,72(4):632-634
Shinnery oak (Quercus havardii) is a native clonal shrub that contributes to an imperiled biotic community in the southern Great Plains of North America. Nevertheless, there is little information on shinnery oak ecology and this lack of information hinders potential restoration of shinnery oak in areas where it has been eliminated. We provide findings from a study conducted to assess emergence and seedling survival from acorns collected in western Oklahoma in 2016. We observed that cold stratification treatments (i.e., acorns stored at 2°C for 2 weeks) and greater acorn size resulted in higher emergence. Although we found no effect of acorn size on seedling survival, we observed that shade reduced seedling survival (P < 0.005). Our study provides previously unknown information on several fundamental aspects of shinnery oak ecology and offers a baseline for restoration efforts by documenting successful shinnery oak emergence and factors associated with seedling survival. 相似文献
20.
对三峡地区灌丛草地灌木植被在山羊放牧条件下的数量特征进行了定量研究。结果表明，不同放牧强度处理区内灌木种间平均重要值的大小均存在着显著差异(P＜0.05)，各区内平均重要值最大者均为白栎，对照、轻牧和重牧区内其平均重要值分别为57.1%、51.3%和39.7%。放牧(轻牧和重牧，5月、7月和9月)期间白栎的重要值为上升趋势(除9月重牧之外)，美丽胡枝子的重要值为下降趋势(除5月轻牧之外)，水锦树的重要值为上升趋势(除9月轻牧之外)。轻牧能使白栎、麻栎、盐肤木、柳杉、美丽胡枝子、马桑和小果蔷薇的重要值增加，这说明轻牧在一定程度上能促进它们的再生，增加植冠盖度，从而提高它们在灌木群落中的优势地位。而对于某些粗蛋白质含量较高的灌木种，如宜昌木兰和黄檀等，放牧会影响其再生，故应严格控制其放牧强度才不致使其从灌木群落中衰减甚至消失。 相似文献