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紫翅猪毛菜的种子多型性及其结实格局 总被引：7，自引：0，他引：7
紫翅猪毛菜(Salsola affinis)主要分布于新疆准噶尔荒漠, 具有很强的抗干旱和耐盐碱能力, 其种子具有多型现象。我们对紫翅猪毛菜的种子形态、萌发特性及结实格局进行了观测研究。结果表明: (1) 紫翅猪毛菜3种类型的种子在形状、大小、颜色、着生方式及包被其花被片背部是否具翅方面均有明显不同; (2) 3种类型的种子具有不同的散布特性和萌发行为: A型种子容易从母体脱落, 发达的果翅能够借助风进行远距离传播; B、C型种子成熟时紧连母体, 不易脱落。在变温下A型种子和B型种子能够快速萌发, 且B型种子比A型种子的萌发速度快; 而C型种子萌发缓慢, 最终萌发率小于10%, 表明其处于休眠状态; (3)随植株个体的增大, A型种子所占比例逐渐增多, 由0.43%增加到51.07%; B型种子所占比例逐渐减少, 由65.80%减少到18.06%; C型种子所占比例没有显著变化, 约为30–35%。紫翅猪毛菜的种子多型性以及种子输出的灵活性有利于其在荒漠异质环境中成功定居。对种子多型性及其结实格局的研究将为探讨其生态适应机制及生活史进化研究提供科学依据。 相似文献
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异苞滨藜的果实(种子)存在二型性,这两种类型的果实在形状、大小、颜色及包被其苞片的大小上均有差异。黑色果实果皮光滑,有光泽,直径1.481mm±0.186mm,包被果实的苞片较小;褐色果实扁平,直径2.642mm±0.254mm,包被果实的苞片较大。以异苞滨藜的两种果实(种子)为材料,在3个变温条件(5/25℃、5/15℃、15/25℃,暗12h/光12h)下进行萌发实验,褐色种子成熟后即具有一定的萌发能力,最终萌发率都在80%以上。黑色种子仅在低的夜间温度(5℃)和高的昼间温度(25℃)条件下有较高的萌发率(>70%),而在5/15℃、15/25℃条件下,种子的最终萌发率较低(<20%),2星期的低温层积处理能够有效地加速和提高黑色种子在3个变温条件下的萌发,划破果皮和种皮也能不同程度的加速和促进黑色种子的萌发,表明黑色种子处于非深度生理休眠状态。苞片中盐含量低,苞片对褐色种子萌发无抑制作用。异苞滨藜的果实(种子)二型性及其萌发行为是对荒漠异质环境的适应。 相似文献
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二型性种子可能增强植物(尤其是盐生植物)应对难于预测环境变化的能力。该研究以运城盐湖盐地碱蓬(Suaeda salsa)二型性种子(黑色和棕色)为材料,采用室内观察和萌发方法对两种种子的形态、休眠和萌发特性进行比较,以揭示盐生植物二型性种子对盐渍化环境的适应对策。结果表明:(1)黑色种子体积小,种皮角质有光泽,而棕色种子体积大,种皮膜质无光泽。(2)新成熟的棕色种子在实验温度范围内萌发率均超过90%,而黑色种子仅在15/25℃下萌发最高(但低于85%),并且棕色种子萌发速度较黑色更快。(3)低盐(0.39mol/L)条件下,光照或黑暗对棕色种子萌发没有显著影响;高盐(0.39mol/L)条件下,棕色种子在黑暗中的萌发显著高于光照环境,而黑色种子在光照条件下的萌发率显著高于黑暗;所有温度和光照处理中,2种种子均随盐分浓度的升高而下降,但棕色种子在盐分浓度为0.78mol/L时萌发率仍能够达到30%以上,而黑色种子在盐分浓度大于0.59mol/L时几乎不萌发。(4)棕色种子为非休眠种子,而黑色种子具有非深度生理休眠特性;划破种皮、干储、低温层积和GA3处理均能够提高黑色种子的萌发率。研究发现,盐地碱蓬通过二型性种子休眠和萌发行为上的差异,采用\"两头下注\"对策提高其对盐渍化异质生境的适应性。 相似文献
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种子萌发和休眠的调控 总被引：11，自引：0，他引：11
种子的萌发和休眠受外界因子和种子本身的特征如种子的结构、植物激素的含量以及种子所携带的遗传信息等的影响。在种子发育后期,种子成熟脱水,处于发育停滞(develop-mental arrest)。在这个阶段,种子可能是休眠(初生休眠)或者是非休眠(图1)。休眠种子不可能被完全适合的萌发条件诱导萌发。通常应用一定的温度范围能够打破干燥种子的 相似文献
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山茱萸种子的休眠原因与萌发条件 总被引：7，自引：1，他引：7
山茱萸种子的萌发受到种皮抑制物、胚生理后熟程度以及当年低温的阻抑。种子秋播后需经3个月高温(15～22℃)、2个月低温(5～16℃)的湿沙层积,才能完成生理后熟,于次年春天萌发。并研究了种子层积过程中氧的作用、种皮的单宁和ABA含量、胚乳转化、G6PDH(6—磷酸葡萄糖脱氢酶)和 6PGDH(6—磷酸葡萄糖酸脱氢酶)与萌发的关系。 相似文献
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龙眼种子的休眠特性及萌发生理 总被引：5，自引：1，他引：5
本文对有休眠现象的顽拗型龙眼(Dim-ocarpus longan )品种“乌圆”种子的休眠生理特性作了一些检测,获得如下几个方面结果。1.与温度的关系新采收的龙眼种子(含水量约为37.5％)于5～35℃下可以萌发,5℃下萌发的速度极慢,15～25℃下发芽率均可达100％,其中25℃下萌发的时间最短,只需7天,15℃下则需20天,而于30℃和35℃下萌发20天的发芽率却分别只有76.7％和73.3％(图1)。将置于30℃和 相似文献
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异子蓬为中亚荒漠的特有种,其果实为胞果,花被片在结果时宿存包被果实形成浆果状的散布单位.对异子蓬的散布单位、果实形态进行比较观察,并在5/15℃、5/25℃、15/25 ℃(暗/光=12h/12h)3个温变周期下进行种子萌发实验,结果表明:(1)异子蓬的散布单位绿色、浆果状,有大小两种形态;大小两种散布单位内包被的果实在形状、大小、颜色上存在着明显差异.(2)大的散布单位内包被的果实圆形,扁平,褐色,无光泽,直径(2.64±0.03) mm,重量(3.68±0.04) mg;小的散布单位内包被的果实双凸镜形,黑色,有光泽,直径(2.40±0.04) mm,重量(2.86±0.06) mg.(3)褐色种子在3个温变周期下的萌发率都在81%以上,萌发速度快,而黑色种子萌发率低,萌发慢,具有休眠现象.(4)划破种皮及低温层积处理可显著提高黑色种子在3个温变周期下的萌发率,延长储存时间也可有效地促进黑色种子的萌发,表明黑色种子处于非深度生理休眠状态.异子蓬产生的两种不同类型的种子及其在时间和空间上的萌发差异对荒漠异质环境具有重要的适应意义. 相似文献
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凤丹种子的休眠和萌发特性 总被引：40，自引：1，他引：40
先高温后低温处理可以解除凤丹种子的休眠,凤丹种子萌发需要经历严格有序的后熟,长根和长芽三个阶段,某一阶段的条件不能满足或不按上述顺序进行,即不能萌发成苗。ＧＡ３可代替低温提高凤丹种子的萌发率。 相似文献
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Y. S. Athugala K. M. G. G. Jayasuriya A. M. T. A. Gunarathne C. C. Baskin 《Plant biology (Stuttgart, Germany)》2018,20(5):916-925
- Fruiting season of many Sri Lankan tropical montane species is not synchronised and may not occur when conditions are favourable for seedling establishment. We hypothesised that species with different fruiting seasons have different seed dormancy mechanisms to synchronise timing of germination with a favourable season for establishment. Using six species with different fruiting seasons, we tested this hypothesis.
- Germination and imbibition of intact and manually scarified seeds were studied. Effect of GA3 on germination was examined. Embryo length:seed length (E:S) ratio of freshly matured seeds and of those with a split seed coat was determined. Time taken for radicle and plumule emergence and morphological changes of the embryos were recorded.
- The radicle emerged from Ardisia missionis, Bheza nitidissima and Gaetnera walkeri seeds within 30 days, whereas it took >30 days in other species. Embryos grew in seeds of B. nitidissima and G. walkeri prior to radicle emergence but not in Microtropis wallichiana, Nothapodytes nimmoniana and Symplocos cochinchinensis. A considerable delay was observed between radicle and plumule emergence in all six species. Warm stratification and/or GA3 promoted germination of all species.
- All the tested species have epicotyl dormancy. Seeds of B. nitidissima and G. walkeri have non‐deep simple morphophysiological epicotyl dormancy, and the other four species have non‐deep physiological epicotyl dormancy. Differences in radicle and epicotyl dormancy promote synchronisation of germination to a favourable time for seedling development. Therefore, information on dormancy‐breaking and germination requirements of both radicle and epicotyl are needed to determine the kind of dormancy of a particular species.
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With the purpose of assessing the status of dormancy in seeds of two Begonia species (Begonia lithophila and Begonia guishanensis), freshly matured seeds were given gibberellic acid and moist chilling and allowed to dry after ripening. The seeds were then germinated on media with or without KNO3 at 15, 20, 25, 30 and 18/25°C. All three treatments significantly increased germination percentages. Examination by X‐ray revealed that seeds of both species have a fully developed embryo and thus have no morphological component of dormancy; seeds readily imbibed water and KNO3 solution. Therefore, we conclude that seeds of the two Begonia species have non‐deep physiological dormancy. Although KNO3 significantly increased germination in both species, alternating temperatures did not, suggesting that the most favorable microhabitat for germination is small‐scale disturbances under the forest canopy. 相似文献
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V. Thusithana R. W. K. Amarasekara K. M. G. Gehan Jayasuriya N. S. Gama‐Arachchige C. C. Baskin J. M. Baskin 《Plant biology (Stuttgart, Germany)》2021,23(1):148-155
- This study investigated seed germination of Cardiospermum halicacabum, a medicinally important invasive species.
- We compared mass, moisture content (MC), dormancy and dormancy‐breaking treatments and imbibition and germination of scarified and non‐scarified seeds of C. halicacabum from a low‐elevation dry zone (DZ), low‐elevation wet zone (WZ1) and mid‐elevation wet zone (WZ2) in Sri Lanka to test the hypothesis that the percentage of seeds with water‐impermeable seed coats (physical dormancy, PY) decreases with increased precipitation.
- Seed mass was higher in WZ2 than in DZ and WZ1, while seed MC did not vary among the zones. All scarified DZ, WZ1 and WZ2 and non‐scarified DZ and WZ1 seeds imbibed water, but only a few non‐scarified WZ2 seeds did so. When DZ and WZ1 seeds were desiccated, MC and percentage imbibition decreased, showing that these seeds have the ability to develop PY. GA3 promoted germination of embryos excised from fresh DZ and WZ1 seeds and of scarified WZ2 seeds.
- At maturity, seeds from DZ and WZ1 had only physiological dormancy (PD), while those from WZ2 had combinational dormancy (PY+PD). Thus, our hypothesis was not supported. Since a high percentage of excised embryos developed into normal seedlings; this is a low‐cost method to produce C. halicacabum plants for medicinal and ornamental purposes.
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Abstract Seed germination is dependent on the interaction between the dormancy state of a seed and the presence of favourable environmental conditions. Thus, the spectacular pulse of seedling recruitment in many Australian vegetation communities following disturbances such as fire can be attributed to changes in microsite conditions and/or the dormancy‐breaking effect of the disturbance on accumulated seed banks. Grevillea rivularis is a threatened species endemic to the area immediately above Carrington Falls in the NSW Southern Highlands. Most of the population is confined to the riparian vegetation zone in woodland and heath, and is therefore subject to periodic disturbance from fire and flood. For this species, a pulse of seedling recruitment has been recorded after fire, flood and mechanical soil disturbance. The aims of this study were to examine the density and vertical distribution of the soil‐stored seed bank and to investigate the role of heat and scarification as cues for germination of fresh and soil‐stored seed. There was a large seed bank under the canopies of established individuals (194 ± 73 seeds m?2) and most seeds were found in the 0–2 cm and leaf‐litter layers of the soil profile. The germination response of soil‐stored and fresh seed was examined using a hierarchical series of laboratory experiments. Seeds of G. rivularis showed marked dormancy polymorphism. Thirty‐six percent of soil‐stored seed germinated without treatment, whereas no untreated fresh seeds germinated. Scarification or heating caused significant germination of dormant soil‐stored seed, but only scarification resulted in germination of dormant fresh seeds. These results highlight important differences in the dormancy state of soil‐stored and fresh seed. Thus, being a riparian species in a fire‐prone environment, the dormancy mechanisms in seeds of G. rivularis suit this species to disturbance by both fire and flood. 相似文献
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- Dormancy cycling is a key mechanism that contributes to the maintenance of long‐term persistent soil seed banks, but has not been recorded in long‐lived woody shrub species from fire‐prone environments. Such species rely on seed banks and dormancy break as important processes for post‐fire recruitment and recovery.
- We used germination experiments with smoke treatments on fresh seeds and those buried for 1 year (retrieved in spring) and 1.5 years (retrieved the following late autumn) to investigate whether Asterolasia buxifolia, a shrub from fire‐prone south‐eastern Australia with physiologically dormant seeds, exhibited dormancy cycling.
- All seeds had an obligation for winter seasonal temperatures and smoke to promote germination, even after ageing in the soil. A high proportion of germination was recorded from fresh seeds. but germination after the first retrieval was significantly lower, despite high seed viability. After the second retrieval, germination returned to the initial level. This indicates a pattern of annual dormancy cycling; one of the few observations, to our knowledge, for a perennial species. Additionally, A. buxifolia’s winter temperature and smoke requirements did not change over time, highlighting the potential for seeds to remain conditionally dormant (i.e. restricted to a narrow range of germination conditions) for long periods.
- For physiologically dormant species, such as A. buxifolia, we conclude that dormancy cycling is an important driver of successful regeneration, allowing seed bank persistence, sometimes for decades, during fire‐free periods unsuitable for successful recruitment, while ensuring that a large proportion of seeds are available for recruitment when a fire occurs.
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由于受种子生理休眠作用的影响和硬而厚的种皮所产生的抑制作用,使海甘蓝（ＣｒａｍｂｅｍａｒｉｔｉｍａＬ．）种子发芽慢,发芽率低。为探索加快海甘蓝种子发芽和提高种子发芽率的有效方法,我们先后进行了８种不同的种子预处理试验和６种不同次氯酸钠溶液浸种的发芽试验。结果发现：（１）种子剥皮处理可以很大程度地促进发芽和提高发芽率;（２）用浓度为０．０５％的赤霉酸溶液浸种１８ｈ对海甘蓝种子发芽也有很好的促进作用;（３）用０．２０％的代森锰锌４５Ｍ（Ｄｉｉｔｈａｎｅ４５Ｍ）溶液浸种２０ｍｉｎ的消毒处理对海甘蓝种子发芽产生一定程度的抑制作用,但可减少海甘蓝幼苗死亡率;（４）适宜浓度的次氯酸钠漂白水（法文名１＇ＥａｕｄｅＪａｖｅｌ）的溶液（１０％）浸种５ｍｉｎ对促进海甘蓝种子发芽和减少幼苗死亡均有良好效果;浓度低于１０％时．不足以腐蚀种子硬而厚的种皮而促进种子发芽,也不足以杀死种子携带的病菌而减少幼苗死亡率;浓度大于１０％时,对种子的胚和种子内的酶活性产生不良影响,从而抑制种子发芽和影响幼苗的正常生长。 相似文献
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角果碱蓬(Suaeda corniculata)是藜科一年生盐生植物, 在我国分布于北方盐碱滩涂和盐碱荒漠地区。角果碱蓬具有棕色和黑色两种异型体种子(简称棕色和黑色种子)。对采自内蒙古鄂托克前旗盐渍化生境的角果碱蓬二型种子的形态、休眠和萌发特性开展对比研究, 测定了二型种子休眠和萌发行为对温度、光照和盐分(NaCl)的响应, 以揭示盐生植物异型种子对温带盐漠生境的适应对策。结果表明: (1)二型性种子在大小、种皮特性和结实比例方面有显著差异。与黑色种子相比, 棕色种子个体较大, 种皮透水性强。黑色种子与棕色种子的结实比例约为5.6 : 1。(2)新成熟的棕色种子的萌发对各温度梯度和光照条件不敏感, 萌发率较高(84%-100%); 而新成熟的黑色种子萌发率较低(8%-78%), 萌发对光照敏感。(3)黑色种子具有浅度生理休眠, 种皮划破、赤霉素处理和低温层积均可有效地提高种子的萌发率。(4)二型种子萌发对土壤盐分的胁迫具有不同的响应。与黑色种子相比, 棕色种子对盐分胁迫不敏感, 在较高的盐分浓度下仍有较高的萌发率, 低温层积处理能够降低黑色种子对盐胁迫的敏感性, 有效地提高种子的初始萌发率、萌发恢复率和最终萌发率。角果碱蓬二型种子不同的形态、休眠和萌发特性, 提高了该物种在高度异质性生境中的适合度, 对种群成功地适应温带盐漠环境具有重要的意义。 相似文献
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Helianthus annuus is an invasive alien species naturalised in the central region of Argentina where it shares an extended area with the sunflower crop. As this species has also invaded several other sunflower crop growing areas in the world, it severely restricts the use of new technologies, for example herbicide tolerance by genetic modification. The natural seed dormancy of the wild Helianthus strains from the centre of origin in North America is well known, but the seed dormancy of the invasive biotypes is still unknown. Dormancy is a fitness trait related to the establishment, dispersion and persistence of invasive weeds. Four experiments were designed to investigate the effect of the pericarp, light, temperature, the after‐ripening period and hybridization with the DK3880CL sunflower crop (F1) on the seed dormancy of five invasive H. annuus biotypes. The results showed that pericarp scarification increased imbibition of the whole achene by 19%. Light stimulation only increased germination in the wild biotype without any effect on the domesticated sunflower. A period of 12 months after‐ripening at 5°C reduced seed dormancy in the wild biotype and its progeny; the optimal temperature for seed germination at this period was found to be 15°C. Mechanical scarification was the best treatment for overcoming seed dormancy with a differential germination, in the biotypes with the highest response, superior to 63%. Hybridization with domesticated sunflower had a minimal or no effect on seed dormancy but the germination rate was improved in three F1 crosses. Wild biotype dormancy appears to be governed by the maternal pericarp and intrinsic hormone regulation. An increased germination rate of some progenies could constitute an advantage during seedling establishment but only in winters without any frost. 相似文献
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羊草种子休眠机制及破除方法研究 总被引：5，自引：1，他引：5
羊草种子休眠程度深、发芽率低是限制栽培利用的重要因子.采用不同破除羊草种子休眠的方法,测定各处理对种子萌发的影响,以探索破除羊草种子休眠的有效途径.结果显示:(1)刺破种皮的裸种子较完整种子的萌发率、吸水速率、生活力分别由对照的6%、63%、0%显著增加到60%、86%、94%.(2)完整羊草种子分别用清水浸种1 d、30% NaOH浸种80 min、清水浸种1 d后用30% NaOH浸种60min其萌发率由6%分别显著提高到36%、60%、84%,而各浓度赤霉素处理完整种子其萌发率较对照均无显著变化. (3)采用清水浸种1 d后用30% NaOH处理60 min,再施加200 μg/g GA3综合处理,可使羊草完整种子的发芽率由6%提高到91%,接近其种子生活力94%.研究表明,羊草种子的稃与种皮不影响种子水分的吸收,但影响种子对GA3的吸收、不同程度地阻碍大分子物质的渗入、限制羊草种子内部萌发抑制物的渗出,从而引起种子休眠;分析认为稃和种皮以及种子内部萌发抑制物质是引起羊草种子休眠的主要原因. 相似文献