南方红豆杉种子休眠特性及催芽技术研究

对南方红豆杉种子进行种皮透水性测定及变温层积处理,研究其休眠特性及催芽技术。结果发现：南方红豆杉种子在自然条件下发芽需要2~3a,休眠期限长,导致其深休眠的主要因素是种子内所含的萌发抑制物质及种胚的发育程度等;对新鲜种子进行层积处理后,能很好地消除体内抑制物含量,且以25℃,层积130d后,再转入5℃,层积80d的“暖温-低温”湿沙变温层积处理,消除发芽抑制物的效果较好,其种子甲醇浸提液的比较发芽抑制率（W100）从6489%降至851%,胚长增长042mm,种子平均发芽率达760%。     

黑龙江省农田多年生杂草日趋严重的原因及新型防除技术研究概述

概述了黑龙江省农田多年生杂草逐渐成为农田杂草群落优势种类的主要原因,分析了其难防除的生物学机理,在此基础上提出了新的防除方法设想,并探讨了多年生杂草在越冬休眠进程中体内一些物质的变化规律。     

Effects of variation in seed sources and pre-sowing treatments on seed germination of Tamarindus indica: a multi-purpose tree species in Bangladesh

We investigated the morphology and germination of Tamarindus indica seeds in order to discover the effects of variation in seed sources and pre-sowing treatments on germination. The experiment was carried out in the nursery of the Forestry and Wood Technology Discipline, Khulna University, Bangladesh. Seeds were collected from different but healthy trees from various locations in Bangladesh and subjected to four pre-sowing treatments, i.e., control, immersion in cold water (4°C for 24 h), immersion in hot water (80°C for 10 min) and scarification with sand paper. Seed germination was carried out in poly-bags with a mixture of topsoil and cow dung in the ratio of 3:1. The average length of the fresh seeds was 1.35±0.26 cm, their width 1.07 ±0.20 cm and thickness 0.69±0.11 cm. The results revealed that pre-sowing treatments affected the germination process of seeds, which significantly increased the germination percentage with the cold water (81.67%) and scarification with sand paper (82.33%) treatments, compared with those in the control (58.33%) and hot water treatment (59.00%). In all treatments germination started on average within 5 to 7 days after the start of the treatments and were completed from 13 to 19 days later. The greatest success in germination (82.33%) was found in scarification with sand paper, followed with 81.67% in the cold water treatment. The results of analyses of variance (ANOVA) showed significant differences (p<0.05) in germination closing dates, seed germination periods and germination percentages among the treatments but no significant difference among seed sources. However, the effect of the interaction between seed source variation and pre-treatment differed significantly in seed germination closing dates and germination percentages. We recommend cold water treatment (submersion of seed at a temperature of 4°C for a 24-h period) for seed germination of T. indica in rural Bangladesh.     

光周期和温度对胭脂花生长发育的影响

为探讨人工栽培条件下胭脂花的生长发育规律,开发实用的胭脂花栽培技术,以胭脂花休眠植株为试验材 料,研究了15 与20 c2 种温度和16、12、8 h 3 种日照长度对解除胭脂花植株休眠及解除休眠后植株生长发育的影 响。结果表明:1)光周期和温度对解除胭脂花植株休眠和生长发育均有显著影响,光周期是解除休眠、促进萌发 (对植株萌发的贡献率为79.89%)和生长发育(对生物量的贡献率在78.66% 以上)的重要因素;16 h 日照长度处 理20 d 可彻底打破胭脂花的休眠,促进萌发和快速生长,日照短于12 h 时胭脂花植株则持续处于休眠状态或生长 缓慢。2)16 h 日照长度和15 c温度组合最适合胭脂花的生长发育,该条件下植株生物量最大(干质量达到2.375 g),主根发达,花芽分化效果好,并有部分植株开花。16 h 日照长度下,20 益温度处理的植株生长速率在前期高于 15 益处理,但后期叶片大量萎蔫,长势衰弱,根系活力低。试验结果说明,胭脂花适宜在长日照及较低温度条件下 生长,短日照可诱导植株休眠,20 c以上温度不利于其生长发育。      

Purple nutsedge tuber sprouting

Purple nutsedge ( Cyperus rotundus L.) tubers remain viable for several years and serve as its principal means of survival. The maintenance of high moisture content is essential to tuber survival. Apical dominance influences bud dormancy within a tuber and in a chain of tubers, and dormancy increases with tuber age. Several growth inhibitors were identified in tubers, but their role in tuber dormancy has not been established. Moisture levels in soil must increase to a critical level before sprouting occurs, but excess soil moisture deters sprouting. Oxygen may be a limiting factor for tuber sprouting in waterlogged soils. Although light is not a requirement for sprouting, it has promoted sprouting. Temperature regulates sprouting; no sprouting occured below 10°C and above 45°C. Optimum sprouting occurred between 25 and 35°C when provided with constant temperatures. However, daily alternating temperatures greatly stimulated sprouting. A daily short duration (0.5 h) of high temperature increased sprouting to nearly 100%, whereas less than 50% sprouting occurred without the daily high temperature pulse. Bud break occurred readily for most tubers at 20°C and in nearly 100% of the tubers with a single 0.5 h exposure to a high temperature (35°C) pulse. However, most buds did not elongate if the tuber remained at 20°C. Bud elongation occurred at higher temperatures, and daily alternating temperatures stimulated shoot elongation up to eightfold greater than at the respective mean constant temperatures. Daily soil temperature fluctuation may be a major signal for purple nutsedge emergence, such as when the plant canopy is removed, or when soils are solarized. Future research is needed to determine tuber sprouting for different ecotypes, and on the role of the rhizome chain. Systems to manipulate sprouting may provide new strategies for purple nutsedge management.     

不同秋眠类型苜蓿品种生产性能与持久性分析

通过对58份不同秋眠类型苜蓿品种再生性、持久性和产草量在呼和浩特的测定分析,结果表明:1)在全部参试材料与秋眠类型组中,苜蓿秋眠级和再生性正相关并达到极显著、显著水平;而在半秋眠类型组、非秋眠类型组中,苜蓿的再生性和秋眠级相关性很小。2)在全部参试材料、半秋眠类型组、非秋眠类型组中,首蓿的持久性与秋眠级负相关,但是在秋眠类型组中,首蓿秋眠级和持久性相关性很小。3)在全部参试材料、半秋眠类型组、非秋眠类型组中,苜蓿的产草量和秋眠级负相关;在秋眠类型组中,苜蓿的产草量和秋眠级正相关但不显著。     

Seed dormancy and germination in the summer annual Galeopsis speciosa

This study examined germination and dormancy in Galeopsis speciosa (Lamiaceae), a common summer annual weed in cold‐temperate areas. Seeds collected in southern Sweden were subjected to several experiments. The seeds were dormant at maturity. Seeds sown outdoors after collection produced a small number of seedlings that emerged early in the spring. After long cold stratification or stratification outdoors over two winters, the maximum germination was 40–50%; germination occurring over a wide range of temperatures. Warm stratification preceding cold stratification had no effect on germination, but repeated warm and cold periods seemed to promote germination. Gibberellic acid (GA) stimulated germination, but full germination was only achieved after more than 2 months of incubation at the most suitable temperature regime tested. Excised embryos grew and developed into normal seedlings. With these results, the species does not fit into the currently used system for seed dormancy classifications. The response to GA and the growth of excised embryos indicate non‐deep or intermediate physiological dormancy, but dormancy alleviation by stratification was not in line with the guiding principles for these classifications. Galeopsis speciosa has a strong dormancy that is sufficiently alleviated during the winter to allow germination of only part of a seed batch each year; hence a stepwise germination pattern occurs over a period of several years.     

低温层积过程中圆齿野鸦椿种子的生理生化变化

通过对不同层积时间圆齿野鸦椿种子萌发及其生理生化变化情况的研究,得出种皮对圆齿野鸦椿种子萌发具有很强的机械障碍,仅通过低温层积不能完全解除种皮的机械障碍.低温层积配合60℃温水浸种能够有效解除休眠.同时通过实验发现,当采取播前温水处理打破种皮机械障碍时,以低温层积90～120 d为宜,层积时间过长会导致萌发率降低.通过实验,对低温层积不同时间的圆齿野鸦椿种子生理生化变化情况进行测定,结果表明:随着层积时间增加,可溶性糖含量与G-6-PDH和6-PGDH联合酶活性波动上升,而淀粉含量波动下降.说明种子内含物质相互转化,逐步解除休眠,同时种子呼吸代谢中戊糖磷酸途径所占比重上升.POD活性先逐渐上升,在120 d后活性下降,笔者认为这可能是导致层积120 d后种子萌发率降低的主要原因.     

贵州地区不同秋眠级苜蓿品种根系发育能力研究

从根系发育角度对美国11个秋眠级标准对照苜蓿品种在贵州地区的适应性进行研究。结果表明,苜蓿随着秋眠级升高,根颈直径呈先减小后增大的趋势,最大的是UC-1887(FD10),为1.439 cm;主根长度呈先增长后减小的趋势,最长的是Pierce(FD8),为59.75 cm;侧根数逐步减少,最多的是Vernal(FD2),为19.33;最少的为Pierce(FD8),为12.25。主根直径、主根体积、主根生物量、侧根体积、侧根生物量及根系体积、根系生物量都呈增大的趋势,苜蓿第1年根系主要集中在0~20 cm土层,根系体积所占比例为77.82%～92.35%,根系生物量所占比例为75.14%～90.96%。通过聚类分析及不同秋眠级苜蓿品种的综合表现,在贵州地区,苜蓿根系发育能力较强的秋眠级为7～10。     

蒜种贮藏温度和空气湿度对大蒜生理及二次生长的影响

贮藏期间蒜种呼吸增强,乙烯含量降低,低温贮藏促进这些变化;随空气湿度增大,蒜种呼吸及含水量有增加趋势。鳞茎形成过程中鳞茎中游离氨基酸减少,蔗糖和果糖增加,低温贮藏蒜种加快了这一进程。贮藏温度效应大于湿度效应,低温(5℃)和高湿(75％或100％RH)贮藏蒜种对初级生长及二次生长促进最显著。贮藏温度越低,外层型二次生长(SGo)越严重;内层型二次生长(SGi)与蒜种贮藏温度呈‘V’型曲线关系。低温下,高湿贮藏蒜种较低湿(25％或50％RH)贮藏蒜种SGo及SGi均极显著增加。