矮沙冬青种子特性和萌发影响因素的研究

 对矮沙冬青(Ammopiptanthus nanus)种子的特性和萌发影响因素进行了初步研究,结果表明：种子不易传播;虫蛀率高,室温贮藏60 d的种子虫害率为38%;易形成硬实,含水量为7.68%的种子在30 ℃温水中浸泡90 h,只有33.33%能吸水膨胀。种子萌发时不需光,在15～30 ℃和室温（18～32 ℃）条件下,经9 d的萌发,发芽率均可达80%以上,30℃时萌发最快;在1～2 cm深的沙壤中,种子出苗率可达75%以上,超过3 cm显著降低,超过6 cm则低于20%;种子在沙壤中萌发时,沙壤的适宜湿度为19.35%～28.75%,高于32.43%或低于3.85%,很少有种子萌发;含水量分别为19.36%、10.64% 和7.68%的种子发芽率无显著差异,在-10 ℃和5 ℃下贮藏7个月,发芽率也无显著降低,但在室温和35 ℃下贮藏7个月则显著下降,发芽率下降的速度与种子本身的含水量和贮藏温度正相关;在湿度分别为7.41%、13.79%和28.57%的沙壤中播种育苗,幼苗死亡率高达77.49%、81.25%和89.49%,即使用三唑酮拌种,死亡率亦高达50.27%、69.53%和76.03%,幼苗死亡率与沙壤湿度正相关。     

受冷害豆类种子的活力测定问题

在农林生产上一贯采用常规发芽法测得种子发芽率作为判断种子质量的主要指标。种子发芽率是指在合适的发芽条件下,已萌发的种子占全部用来发芽的种子之百分比。在多数情况下,它与“田间出苗率”存在相关性,但有时也并不如此,即发芽率高时,田间出苗率并不高。这是由于种子整齐度,抗逆力和贮存条件引起的老化过程,往往不能用最适条件下的发芽率反映出来。因此从农林生产的角度着眼,需要的不是“发芽率”的指标。而是“出苗率”和“幼苗生长势”的指标。从而在种子生理领域就有一     

不同温度及盐碱环境下盐地碱蓬的萌发策略

为了研究黄河三角洲优势种盐地碱蓬在不同胁迫环境条件下的萌发策略,分别在不同温度、盐度、碱度以及海水原溶液条件下,进行了室内萌发实验,并且测量了其幼苗体内的Na+和K+含量.结果表明,盐地碱蓬种子发芽所需要的积温和最低温度分别为24.57℃·d和0.62℃,最适发芽温度为20℃～35℃,在温度5℃～40℃下均表现出较高的发芽率而且5℃～35℃下发芽速度随温度升高而显著增加.盐地碱蓬具有较高的耐盐性,当盐浓度达到500 mmol·L-1时,发芽率均高于50%,并且在100%海水溶液浓度下发芽率也能达到38%,高盐条件下未萌发的种子转移到淡水中,均表现出较高的复萌率.盐地碱蓬幼苗体内Na+含量随盐度(NaCl溶液浓度)升高而显著增加,而K+含量在该盐度下差异不显著;幼苗体内Na+、K+含量在高碱度(200和300 mmol·L-1 NaHCO3)中均显著低于其在低碱度(100mmol·L-1NaHCO3溶液)中的含量,说明碱胁迫对幼苗生长产生了显著性影响;Na+、K+含量均随着海水溶液浓度增加而显著增加.因此,盐地碱蓬种子萌发的广温性、高耐盐性、高盐环境中的种子高存活率以及幼苗的较强的耐盐能力是盐地碱蓬种群在黄河三角洲适应滨海盐碱湿地复杂环境的主要生存策略.     

桔梗种子萌发对低温、干旱及互作胁迫的响应

以药用植物桔梗种子为材料,研究了低温、干旱及其互作对种子萌发和幼苗生长的影响,旨在探索在春寒干旱条件下其种子萌发对策及生态适应性,为桔梗野生种群恢复及人工栽培群体构建提供依据.结果表明,温度、干旱及其互作对桔梗种子萌发和幼苗生长均有显著影响.0-10％ PEG水分条件下,在变温10/20℃及恒温15-25℃下桔梗种子能够良好萌发(10％ PEG、20℃除外),而15％ PEG可显著抑制萌发.低温(10℃)下种子萌发始时间延迟,发芽率降低.随干旱胁迫程度的增加,10℃发芽率呈先升后降趋势,而其它温度下,发芽率和发芽指数均呈下降趋势.随温度的降低,幼苗根长、茎长及鲜重均呈下降趋势,且幼根生长对温度变化更为敏感.     

低温贮藏下真空与非真空包装对小麦种子生活力的影响

对以铝箔袋真空包装和铝盒非真空包装的89份小麦种子,在-4～0℃的低温种质库中贮藏11年后的贮藏效果进行了研究.从种子贮藏后的发芽率与入库前的初始发芽率差异,2种包装方式的种子年份间、同一年份2种方式间的种子发芽率差异等3个方面探讨了2种包装方式的种子在低温贮藏条件下的贮藏效果.结果表明:通过低温贮藏11年的小麦种子生活力测定.82%的材料在低温保存后其种子平均发芽率高于初始发芽率.而贮藏第10年后发芽率才出现较初始发芽率明显下降;铝箔袋包装的种子发芽率下降幅度小于铝盒包装,且差异达显著水平;铝箔袋真空密封包装的贮藏效果明显好于非真空包装的种子.     

在不同气体贮藏下花生种子活力的研究

花生种子(含水量6.21%)在38—40℃下进行人工老化贮藏,N_1和 CO_2空气有延缓种子老化的效果。种子在 N_2或 CO_2气体下老化贮藏26周,发芽率不受影响;而在空气中贮藏的种子,其发芽率几乎丧失。用公式(胚根+下胚轴)mm×发芽率(第5天)来测定花生种子活力。它能够既简单又准确地反映种子老化时品质的变化。花生种子活力与呼吸及幼苗生长有较好的正相关,与浸泡液的电导和糖含量成显著负相关。     

小麦种质贮藏过程中生活力丧失特性及田间出苗率表现

通过对贮藏2～20年的378份中期库小麦种质进行生活力测定(每一贮藏年份测定种质份数为10～30),结果表明贮藏年限为2～12年的种质平均发芽率都高于83％,而贮藏年限为15年的种质平均发芽率已降至20％,这表明小麦种质在中期库贮藏过程中,生活力丧失存在着骤降特性。同时对同一品种分别来自中期库低活力和长期库高活力种质进行田间出苗率和农艺性状调查,发现中期库种质的室内发芽率与田间出苗率相关极显,其相关显性高于长期库种质,且不论是来自中期库低活力种质还是长期库高活力种质,总体上田间出苗率都比室内发芽率低20％以上,在子一代种子的农艺性状上两之间无显差异。     

外来杂草小花山桃草种子休眠萌发特性

种子萌发和出苗是植物一生中对环境胁迫最为敏感的阶段,外来植物在这一时期对环境条件的适应能力是决定其入侵能力大小的关键因素之一。通过室内外试验研究了小花山桃草种子休眠特性以及贮藏时间、果皮、温度、p H值、水势、盐分和埋土深度对其种子萌发、幼苗生长和出苗的影响。结果表明:小花山桃草蒴果中4粒种子的大小差异显著(P0.01),但它们的活力和萌发率差别不大,4粒种子活力均高达96%以上。休眠解除后,萌发率均高达98%以上;坚硬果皮的机械阻碍是引起种子休眠的主要原因;在室温储藏条件下,种子萌发率随贮藏时间的增加先增加后降低。贮藏1个月,萌发率提高到54%(贮藏前为0)。贮藏3—6个月时,萌发率达最大值(98.5%—99%)。贮藏1a后,萌发率和萌发速度显著下降,但萌发率仍高达90%以上;在室外,有10.5%的蒴果前两粒种子(果实柱头端)同时萌发出苗。室外埋藏1a后,蒴果中未萌发的3粒种子的发芽率分别为45.5%、90.5%和88.5%;小花山桃草种子萌发的温度范围为5—35℃,15—25℃最适于种子萌发,25℃最有利于幼苗生长;小花山桃草能忍受一定的盐胁迫和干旱胁迫,盐浓度和水势为0.15 mol/L和-0.5 MPa时,种子萌发率分别为33.5%和9%。种子萌发和幼苗生长最适宜的土壤含水量为50%;小花山桃草对p H值具有较广泛的适应性,在p H值为5—9范围内均可萌发;小花山桃草种子在土壤表面的出苗率为43%,埋土深度2 cm时,出苗率最高(89.5%),埋土深度大于10 cm时,不再出苗。小花山桃草种子休眠萌发特征以及出苗特点是其快速入侵的基础。研究结果为预测小花山桃草潜在分布范围以及提出科学合理的综合治理措施提供了理论依据。     

菜用大豆种子活力与激素关系的初步研究

菜用大豆(Glycine max)品种“六月拔”种子在不同条件下贮藏6个月后分别成为高活力种子(4℃,硅胶干燥贮藏)、中活力种子(自然干燥种子,聚乙烯袋密封贮藏)、低活力种子(自然条件下布袋贮藏)及无活力种子(30℃,90％RH),发芽率分别为90％、50％、30％以上及0。发芽试验方法:取30粒种子置于铺有2层滤纸的15cm培养皿中,在25℃暗中进行发芽,重复3次,2 d计算发芽势,3 d计算发芽率。外     

贮藏条件对益母草、桔梗和白术种子发芽率的影响(简报)

益母草、桔梗和白术3种药用植物种子均不耐贮藏,在收到种子后初始发芽率较低.益母草与桔梗种子萌发适温是25±1℃,而白术种子为15±1℃.在适温下,益母草、桔梗与白术种子的发芽率分别是69.8%、39.8%和46.8%.在15%RH下(硅胶密闭),种子贮藏较适宜,43%RH下贮藏种子的发芽率次之.益母草种子宜在15℃中贮藏,桔梗种子则宜在5℃中贮藏,在5℃下75%RH和43%RH贮藏后的发芽率相近.用PEG6000引发处理桔梗种子可以明显地提高发芽率,但益母草种子则出现负效应.     

Germination and emergence of annual species and burial depth: Implications for restoration ecology

Due to the high content of viable seeds, topsoil is usually spread on ground left bare during railway and motorway construction to facilitate the regeneration of vegetation cover. However, during handling of the topsoil, seeds are often buried deeply and they cannot germinate or the seedlings cannot emerge from depth. This study experimentally explores the predictive value of seed mass for seed germination, mortality and seedling emergence at different burial depths for 13 common annual species in semiarid Mediterranean environments. We separate the effect of burial depth on germination and emergence by means of two experiments. In the germination experiment, five replicates of 20 seeds for each species were buried at depths ranging from 0 to 4 cm under greenhouse conditions. Germinated and empty or rotten seeds were counted after 8 weeks. In the emergence experiment, five replicates of four newly-germinated seeds per species were buried at the same depths under controlled conditions and emergence was recorded after 3 weeks. The effect of burial depth on percentage of germination and seedling emergence was dependent on seed size. Although all species showed a decrease in germination with burial depth, this decrease was greater for small-than large-seeded species. Percentage of emergence was positively related to seed mass but negatively related to burial depth. Seed mortality was higher for small-than large-seeded species, but there was no general effect of burial depth on this variable. Thus, the current practice of spreading 30 cm deep layers of topsoil in post-construction restoration projects is unadvisable. In this restoration scenario, thinner layers of topsoil should be used to achieve the maximum potential of the topsoil for germination and seedling establishment.     

狼毒种子萌发特性与种群更新机制的研究

研究了采集于植株上的和收集于土壤种子库的狼毒(Stellera chamaejasme)种子在不同温度、光照和5种预处理(即破裂种皮、去除种皮、98％H2SO4浸种5min、0．2％KNO3浸种24h、10℃低温保存1周)条件下的萌发力。结果表明,狼毒种子萌发率较低,25℃恒温、黑暗条件下萌发率为13％,较适宜的萌发温度为30℃恒温或10～30℃变温,破裂种皮和去除种皮萌发率显著提高,25℃恒温、光暗交替条件下萌发率分别为49％和47％,浓硫酸浸种5min处理萌发率可达到32％,KON3浸种和10℃低温保存两个处理对促进狼毒种子萌发效果不明显,狼毒种子萌发对光照条件不敏感,种子硬实性是导致狼毒种子萌发率较低的主要原因,取自土壤种子库内的狼毒种子萌发率高于当年采集的种子,在自然条件下,并非每年都有狼毒种子萌发长成幼苗,种群更新时机是随机的或周期性的。     

Effects of seed dispersal on Juniperus communis recruitment on a Mediterranean mountain

Abstract. The recruitment of the relict shrub Juniperus communis on a mountain in SE Spain was studied during the period 1994–1998. The main objective was to determine both the quantitative and qualitative effects of bird dispersal on seedling establishment. Seed removal by birds, seed rain, post‐dispersal seed predation, germination, and seedling emergence and survival were analysed in different microhabitats. Birds removed 53 ‐ 89% of the seeds produced by plants. Seed rain was spatially irregular as most seeds accumulated near stones used by birds as perches and below mother plants while a few seeds were dropped in wet meadows and open ground areas. Post‐dispersal seed predation by rodents affected < 10% of dispersed seeds but varied significantly among microhabitats. Only 3.6 ‐ 5.5% of dispersed seeds appeared viable, as many seeds had aborted or showed wasp damage. Seeds germinated in the second and third springs after sowing, reaching a germination percentage of 36%. Seedling emergence was concentrated in wet meadows. Seedling mortality was high (75–80%), but significantly lower in wet meadows, the only microhabitat where seedlings could escape from summer drought, the main mortality cause. Seed abortion, germination and seedling mortality proved to be the main regeneration constraints of J. communis on Mediterranean mountains. Birds exerted a strong demographic effect, although their qualitative effect was limited by abiotic factors which caused the pattern of seed rain to differ from the final pattern of recruitment between microhabitats.     

沙埋和种子大小对固沙禾草沙鞭的种子萌发与幼苗出土的影响

该文研究了野外条件下不同深度的沙埋对沙鞭(Psammochloa villosa)种子萌发和幼苗出土的影响,以及温室条件下种子大小对不同深度沙埋后的种子萌发和幼苗出土的影响。结果表明,沙埋深度显著影响沙鞭的种子萌发率、幼苗出土率和种子休眠率。沙子表面的种子不能萌发。2 cm的浅层沙埋时的种子萌发率和幼苗出土率最高,1 cm 沙埋的种子萌发率和幼苗出土率次之。沙埋深度超过2 cm之后,沙鞭的种子萌发率和幼苗出土率与沙埋深度呈负相关。2 cm的种子休眠率最低。从2 ~12 cm,种子休眠率随着沙埋深度的增加而增加。在幼苗能够出土的深度(1~6 cm),幼苗首次出土所需的时间随着沙埋深度的增加而延长。种子大小对沙鞭的种子萌发率没有显著影响。但是在深层沙埋(6 cm)时,与小种子相比,大种子产生的幼苗的出土率较高。从2~6 cm,大种子形成的幼苗的茎长度都较长。     

沙埋对六种沙生植物种子萌发和幼苗出土的影响

研究了沙埋对科尔沁沙地6种优势植物的种子萌发和幼苗出土的影响．进行0．2、4、6、8、10和12cm等7个深度沙埋处理．结果表明,在不同沙埋处理时,沙蓬萌发差异显著。而差不嘎蒿2锄埋深与其他埋深的发芽差异显著,其他4种植物0cm埋深与其他埋深的发芽差异显著;沙埋对所有植物幼苗出土均有显著影响,埋深增加,出苗率减小;繁殖体大的物种与繁殖体小的物种相比,能从更深沙层中出苗,幼苗出土最大深度排序为苦参>东北木蓼≥沙蓬>山竹子>雾冰藜>差不嘎蒿．     

Seed germination ecology of Portulaca oleracea L.: an important weed of rice and upland crops

Portulaca oleracea , a C₄ species, is reported to be a serious weed in 45 crops in 81 countries. Experiments were conducted in the laboratory, the screenhouse and the field to determine the influence of environmental factors on seed germination and seedling emergence of P. oleracea . In the laboratory, germination in the dark was low and was not influenced by the tested temperatures (35/25°C, 30/20°C and 25/15°C alternating day/night temperatures). In the light/dark regime, however, germination was lower at 25/15°C and 35/25°C than at 30/20°C (70%, 75% and 81% germination, respectively). In conditions of 106 mM sodium chloride or −0.34 MPa osmotic potential, seeds germinated to only 50% of maximum germination of the control. Germination was not influenced by buffered pH solutions ranging from 5 to 9. In the screenhouse, germination was greatest for seeds placed on the soil surface, but emergence declined with increasing seed burial depth in soil; no seedlings emerged from the depth of 2 cm. Seedling emergence and seedling dry matter were markedly reduced by the addition of rice residue to the soil surface at rates equivalent to 4 to 6 t ha⁻¹. In the field, seedling emergence of P. oleracea was greater under zero till (ZT) (17–20%) than under minimum tillage (6–10%), a likely reflection of low seed burial and exposure of seeds to light with a ZT system. This study identifies some of the factors enabling P. oleracea to be a widespread weed in the humid tropics, and the information could contribute to improved control strategies.     

种皮和环境温度对橡胶树种子萌发的影响

在人工气候箱控制的条件下,研究了种皮和环境温度对橡胶树(Hevea brasiliensis)种子萌发的影响.结果表明,种皮对橡胶树种子的吸水和萌发具有明显的机械限制作用;去除种皮后种子萌发速率加快,萌发指数增大,但萌发率从83.8%下降到47.8%,幼苗活力指数从332.3下降到187.9.15℃以下的温度明显推迟种子萌发,且萌发率下降.去除种皮后的种仁萌发率、萌发指数和幼苗活力指数均随着温度的升高而增大;有种皮种子的萌发率、萌发指数和幼苗活力指数分别在20℃(94.7%)、30℃(1.86)和25℃(374.4)时最大,而萌发速率系数随着温度的升高先增大后减小.在橡胶树栽培和胶园建设中,可利用种皮对种仁水分散失的限制作用以及对低温的不敏感性,有效延长橡胶树种子的贮藏时间,提高萌发率和籽苗质量.     

Canola seed germination and seedling emergence from pre-hydrated and re-dried seeds subjected to salt and water stresses at low temperatures

Low soil temperatures and low water potentials reduce and delay the seed germination of canola (Brassica rapa L., B. napus L.) in western Canada. Germination is also very sensitive to the salinity effects of nitrogen fertiliser placed with the seed, especially when the seed bed is relatively dry. The effects of pre-hydration and re-drying treatment on canola (Brassica rapa L. cv. Tobin) seed germination and seedling emergence at 10°C subjected to either a water or salt stress were determined. Low water potentials, induced by polyethylene glycol (PEG 8000), low soil moisture, or high concentrations of salts, reduced both germination and seedling emergence, and increased the time to 50% germination and emergence of seeds at 10°C. At equal osmotic potentials, Na₂SO₄ was less inhibitory on low temperature germination than either NaCl or PEG, suggesting that the sulphate ion partially alleviated the inhibitory effects of low water potential. Solutions of NaCI produced more abnormal seedlings compared to Na₂SO₄, suggesting that NaCl was more toxic than Na₂SO₄ during seedling development. Pre-hydration and re-drying partially overcame the inhibitory effects of both low water potential and salts on seed germination and seedling emergence at 10°C. The seed treatment increased the germination rate in Petri dishes and seedling emergence from a sandy loam soil. Water potentials or soil water contents required to inhibit 50% germination or emergence at 10°C were lower for treated seeds compared to control seeds. Salt concentrations inhibiting 50% emergence were higher for treated seeds than control seeds. Neither treated nor control seeds produced seedlings which emerged if the soil water content was lower than 9% or when the soil was continuously irrigated with salt solutions of 100 mmol kg^-1 of NaCl or 50 mmol kg^-1 of Na₂SO₄. These results suggest that the pre-hydration and re-drying treatment did not lower the base water potentials at which seedling emergence could occur. Abnormal seedlings were observed in both treated and control seeds, particularly if the soil was watered with NaCl solutions; however, the seed treatment reduced the number of abnormal seedlings.     

国家库贮藏20年以上种子生活力与田间出苗率监测

对34种作物1.4万多份的国家库贮存种子进行了生活力监测,结果表明,贮存20年后,92.9%被监测种子的发芽率仍保持在85%以上,但有155份种子（占被监测份数的1.1%）出现了明显的下降（发芽率从80%以上降至70%以下）。发芽率显著下降的作物包括蚕豆、红小豆、黄麻、蓖麻、甜菜、西瓜、烟草、牧草。小麦等8种作物2078份种子的田间出苗率调查表明,所有种质均有出苗,但有8份种质的出苗率低于10%。出苗率与入库初始平均发芽率存在差别,平均出苗率最高的作物为普通菜豆86.2%,比该批入库初始发芽率平均值低9.3%;平均出苗率最低作物为谷子39.2%,比该批种子的入库初始发芽率平均值低51.3%。总体而言,国家库内保存的作物种子中,多数可安全保存20年以上,尤其是水稻等禾谷类作物种子,但对于蚕豆、红小豆等平均监测发芽率出现显著下降的作物种子需要增加监测频率,以确保种子的长期安全保存。