GA3、ABA对未成熟‘博Ⅱ优15’水稻种子萌发的影响

以未成熟水稻'博II优15'种子为材料,用不同浓度GA3、ABA浸种24 h,研究其对水稻种子萌发的影响.结果表明,GA3 0.10～2.00 g/L处理能极显著促进种子萌发,其中0.50 g/L效果最好,第4天发芽率高于对照(CK)56%;浓度大于0.50 g/L ABA处理显著抑制种子萌发;GA3与ABA协同处理时, GA3/ABA = 1:1(浓度0.05 g/L)和 GA3/ABA = 1:2(浓度0.01 g/L)均能极显著促进种子萌发,第7天种子发芽率分别比CK高30%和20%.进一步研究表明,GA3和ABA对未成熟水稻种子萌发的影响与α-淀粉酶活性相关.     

龙胆种子萌发与水溶性内源抑制物质

龙胆种子中含有一定活性的内源抑制物质,其对白菜幼根生长的抑制活性高于对白菜种子萌发的抑制活性,对龙胆种子自身萌发也有明显抑制作用;室温浸种可部分去除龙胆种子内源抑制物质;以150 μg·mL-1赤霉素变温浸种处理种子,可提高种子发芽率.据此建立了龙胆种子催芽技术和羧甲基纤维素悬浮液播种技术.     

Ce^3+和La^3+对人工老化沙葱种子活力及生理特性的影响

以未老化和人工老化后的沙葱(Allium mongolicum Regel.)种子为材料,采用氯化铈(Ce3+)和氯化镧(La3+)浸种,测定种子萌发和生理指标,探讨Ce3+和La3+浸种对种子萌发、老化种子活力和生理特性的影响。结果显示:(1)在老化0~5 h时,Ce3+和La3+处理可显著促进沙葱种子萌发,提高种子活力;在老化5 h后,Ce3+和La3+处理对种子萌发无明显促进作用。(2)在老化0~15 h时,Ce3+和La3+处理的沙葱种子中抗氧化酶活性和抗坏血酸(AsA)含量提高,其超氧阴离子自由基(O2-·)产生速率、过氧化氢(H2O2)含量和丙二醛(MDA)含量显著降低;在老化15 h后,Ce3+和La3+处理的种子抗氧化酶活性提高、AsA含量降低,O2-·产生速率和MDA含量提高。(3)在老化5 h时,沙葱种子呼吸速率发生跃变达到最大,Ce3+和La3+处理显著降低了种子呼吸速率。(4)Ce3+和La3+处理在老化0~5 h时提高了沙葱种子超弱发光(UWL)强度,但在老化5 h后沙葱种子的UWL强度降低。研究认为,在沙葱种子人工老化初期,Ce3+和La3+浸种处理可以诱导增强种子抗氧化酶活性和提高AsA含量,有效清除因老化产生积累的过量活性氧(ROS),减轻过氧化伤害,提高种子活力;种子老化中后期,其内部ROS产生与清除系统发生紊乱,加剧了ROS对种子结构的损伤,Ce3+和La3+浸种处理的缓解效应丧失。     

羊草种子休眠机制及破除方法研究

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.     

沙埋对西鄂尔多斯珍稀植物种子萌发和幼苗出土的影响

采用不同沙埋深度(0、1、2、3、5、7、10 cm埋深)处理,对内蒙古西鄂尔多斯4种珍稀植物霸王(Zygophyllum xanthoxylum)、沙冬青(Ammopiptanthus mongolica)、蒙古扁桃(Prunus mongolica)和长叶红砂(Reaumuria trigyna)种子萌发及幼苗出土情况进行研究,以揭示其种子萌发特性.结果表明:表层沙土(0 cm埋深)的种子几乎不萌发;除霸王外,其他3种植物在不同沙埋深度处理下的种子萌发率差异显著(P＜0.05);沙埋对4种珍稀植物的幼苗出土均有显著影响,出苗率随着沙埋深度的增加而降低,且遵循指数方程.霸王在2 cm沙埋深度的出苗率最高,其他物种在1 cm沙埋深度的出苗率最高.沙埋深度对幼苗生物量的影响不显著.     

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。     

γ-氨基丁酸浸种对番茄种子及幼苗耐盐性调节的生理机制

以番茄‘金棚一号’为材料,研究了外源γ-氨基丁酸(GABA)浸种处理对NaCl胁迫下种子萌发及幼苗生长和生理代谢的影响。结果显示:(1)NaCl胁迫显著抑制了番茄种子的萌发和胚根生长,同时导致番茄幼苗体内活性氧(O2.-、H2O2)大量积累,膜脂过氧化程度加重,幼苗叶片光合系统Ⅱ活性显著降低,幼苗的生长受到严重抑制。(2)外源GABA浸种能够显著提高盐胁迫下番茄种子的萌发和胚根的生长,并以10.00mmol.L-1 GABA浸种处理效果最好。(3)外源GABA浸种处理显著提高了NaCl胁迫下番茄幼苗根系和叶片抗氧化酶(SOD、POD和CAT)活性,降低了活性氧(O2.-、H2O2)的产生和膜脂过氧化程度,通过维持较高的光合系统Ⅱ活性,促进了幼苗的生长及生物量积累,但GABA的缓解效应存在较大的浓度差异,其中以10.00mmol.L-1 GABA处理效果较好。研究表明,10.00mmol.L-1 GABA浸种处理能够通过促进番茄种子萌发和幼苗生长来缓解盐胁迫的伤害。     

稗草潜在化感物质的排查

针对已报道属于羟基肟酸(丁布)、酚酸和酞酸酯类的稗草潜在的化感物质,本文以水稻、稗草和莴苣为试验材料,对2,4-二叔丁基酚、对羟基扁桃酸2种酚酸以及3种酞酸酯类物质的化感活性进行了研究.采用高效液相色谱法( HPLC)研究了上述5种物质以及丁布在稗草组织、根区土壤和种子萌发液的含量.结果表明:在100μg·ml-1作用浓度下,对羟基扁桃酸对莴苣、水稻以及稗草的种子萌发和幼苗生长的综合抑制活性最弱,2,4-二叔丁基酚化感抑制活性相对最强.酞酸二甲酯、酞酸二异辛酯和2,4-二叔丁基酚这3种物质对稗草的抑制活性大干水稻.通过HPLC只在稗草苗期叶、根和种子萌发液中检测出对羟基扁桃酸,其含量分别为9.72 μg·g-1、7.29 μg·g-1和0.24 μg·ml-1,而其他生长期组织以及根区土壤中均未检出.所有样品均未检测出2,4-二叔丁基酚、丁布和3种酞酸酯类物质.对羟基扁桃酸的浓度-效应试验显示,接近实测浓度(20 μg·g-1)时其对3种受试植物没有显著的化感抑制效应.本研究表明,对羟基扁桃酸不是稗草中主要的化感物质;通过HPLC-标准物质比对方法可以准确分析上述6种化合物,并证实了稗草不含有2,4-二叔丁基酚、丁布和酞酸酯类物质.     

温水浸种对杜仲种子萌发过程中保护酶活性及内源激素含量变化的影响

探讨杜仲（Eucommia ulmoides Oliver）种子萌发过程中保护酶活性及内源激素含量的变化，为其种子破眠及萌发不同时期采取有效处理措施，从而提高出苗率提供参考。利用室温（CK）、40℃、50℃、60℃和70℃不同水温，探讨温水浸种对杜仲种子萌发的影响。种子萌发进程中，利用常规生理生化方法测定种子内超氧化物歧化酶（SOD）、过氧化物酶（POD）活性和丙二醛（MDA）含量，以及酶联免疫法测定赤霉素（GA₃）、吲哚乙酸（IAA）、脱落酸（ABA）和玉米素核苷（ZR）含量。结果表明：①温水浸种处理能提高了杜仲种子的发芽率及发芽势，其中以50℃温水处理最为显著。②与室温浸种处理相比，50℃温水浸种处理提高了种子内SOD及POD活性，减轻了质膜氧化损伤程度，致使MDA含量的持续下降，从而促使种子朝向有利于萌发的方向发展。此外，50℃温水浸种处理在提高种子内促进生长内源GA₃、IAA及ZR含量的同时，并降低了抑制生长的内源ABA含量，致使GA₃/ABA、IAA/ABA和ZR/ABA值均明显高于室内浸种处理，最终促进了杜仲种子的萌发。     

骆驼蓬提取物对玉米种子萌发和壮苗的影响

用不同浓度骆驼蓬提取物浸种处理玉米,研究对玉米种子萌发和壮苗的影响。结果表明,浸种处理后玉米种子的萌发及胚根和胚芽生长明显受抑,且随处理浓度提高抑制增强;但随培养时间的延长,对萌发的抑制减弱,根长和株高增加。0．1g／mL、0．2g／mL、0．3g／mL浓度的骆驼蓬提取液浸种可显著提高玉米幼苗根系活力,促进植株生长,根体积和植株生物量增加,根苗比增大。     

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.     

Light,temperature, dry after‐ripening and salt stress effects on seed germination of Phleum sardoum (Hackel) Hackel

Phleum sardoum is an endemic psammophilous species of Sardinia, growing exclusively on coastal sandy dunes. The effect of glumes on seed germination, germination requirements at constant (5–25°C) and alternating (25/10°C) temperatures, both in the light (12/12 h) and in the dark were evaluated, as well as the effect of a dry after‐ripening period (90 days at 25°C), the salt stress effect (0–600 mmol NaCl) and its recovery on seed germination. The presence of glumes reduced final germination percentages. For fresh naked seeds, high germination percentages were observed at 10°C. Dry after‐ripening increased germination rate at low temperatures, but did not affect final germination percentages. NaCl determined a secondary salt‐induced dormancy which recovery interrupted only partially. Our results highlighted that this species has its optimum of germination during autumn–winter when, under a Mediterranean climate, water availability is highest and soil salinity levels are minimal.     

1株Alternaria sp.真菌菌丝提取物对玉米种子发芽促进作用的研究

从健康的野生山枣根部分离得到1株真菌,经分子鉴定其为支链孢属Alternaria sp.并且对其进行液体培养到生长期后,菌丝体用4层纱布滤出,40℃烘干,研磨后用乙醇浸提3次,合并滤液,并测定其菌丝醇提取物的浓度,配成1、10、100μg/mL的浓度,进行玉米种子催芽试验。结果表明,浓度为1、10μg/mL的醇提取物,均可提高玉米种子的发芽指数,而浓度为100μg/mL的醇提取物则会降低玉米种子发芽指数。     

Effect of salinity,temperature and hypersaline conditions on the seed germination in Limonium mansanetianum an endemic and threatened Mediterranean species

Abstract

Limonium mansanetianum is catalogued as critically threatened (CR) species and it is included in Valencian Catalogue of Threatened Plant Species. Limonium mansanetianum is a gypsicolous species, which only lives in a restricted area to south-centre of Valencia province (Spain). The species is a low-branched woody shrub with summer flowering. The influence of incubation temperature (10°, 15°, 20° and 25°/20?°C) and salinity (0%–3.0% NaCl) on seed germination of L. mansanetianum was studied. Best seed germination was obtained in distilled water controls. Seed germination decreased with an increase in salinity and few seeds germinated at 2.5% and 3.0% NaCl. Optimal temperature regime for germination was 15?°C where germination in 0.5% and 1.0% NaCl was not affected. Recovery and hypersaline conditions experiments showed that L. mansanetianum seeds displayed a greater tolerance to high salinity and temperature stress before germination.     

FACTORS INFLUENCING SEED GERMINATION IN SALICORNIA PACIFICA VAR. UTAHENSIS

The halophyte, Salicornia pacifica var. utahensis (Tiderstorm) Munz produces seed under high salinity conditions, and deposits its seed on saline soil. Experiments were conducted to determine the effect of salinity, temperature and growth regulators on germination. Results indicate that the seeds can germinate at very high salt concentration (5% NaCl). Germination was sensitive to the changes in temperature regimes. At higher 30–20 C, light-dark sequence, no germination occurred at 3, 4 and 5% NaCl treatments. On the other hand, 30% germination did occur at 5% NaCl treatment at a temperature regime of 15–5 C. These seeds required light for germination. Only 50% germination occurred in the non-saline control in the dark and the addition of NaCl further reduced germination. The GA₃ partially alleviated the inhibitory effect of NaCl and darkness. Kinetin did not promote germination.     

Effect of temperature and cold stratification on seed germination of the Mediterranean wild aromatic Clinopodium sandalioticum (Lamiaceae)

A germination study was carried out on seeds of Clinopodium sandalioticum (Bacch. & Brullo) Bacch. & Brullo ex Peruzzi & Conti (Lamiaceae), a wild aromatic plant endemic to Sardinia. Seeds were incubated at a range of constant (5–25°C) and an alternating temperatures regime (25/10°C), with 12 hours of irradiance per day. The results achieved at 10°C were also compared with those obtained after a period of cold stratification at 5°C for three months. Final seed germination ranged from ca. 28% (5°C) to ca. 72% (25/10°C). A base temperature for germination (T_b) of ca. 5°C and a thermal constant for 50% germination (S) of 89.3°Cd were identified and an optimal temperature for germination (T_o) was estimated to be comprised between 20 and 25°C. Cold stratification negatively affected seed viability and germination at 10°C. Although a typical “Mediterranean germination syndrome”, could not be detected for C. sandalioticum seeds, these results were coherent with those previously reported for other Mediterranean Lamiaceae species.     

Toward understanding the ecological role of mucilage in seed germination of a desert shrub Henophyton deserti: interactive effects of temperature, salinity and osmotic stress

Aims

Seeds of Henophyton deserti (Brassicaceae), an endemic saharan shrub in south Tunisia, produce a pectinaceous mucilage layer that can imbibe a large amount of water when wetted. The aim of this study was to explore the role of mucilage in seed germination of this shrub under heterogeneous stressful environments.

Methods

Germination of both intact and demucilaged seeds was tested over wide ranges of temperature, and in iso-osmotic solutions of NaCl and PEG. Recovery of germination after NaCl and Polyethylene Glycol (PEG)-6000 treatment was also tested. The effect of mucilage on water uptake was measured and the structure of the seed investigated.

Results

A considerable proportion of seed mass (30 %) is made up of mucilage, which is extremely hydrophilic and able to increase seed mass by 550 % over dry seeds. Mucilage water uptake appears to be unaffected by salt concentration, while higher concentrations of PEG inhibit mucilage hydration. Mucilage decreases germination specifically at 10 °C and this effect can be interpreted in relation to oxygen uptake. High concentrations of NaCl and PEG decrease both germination percentage and rate, with some greater tolerance at 15 °C and 20 °C versus 25 °C. Recovery was higher from higher concentrations of NaCl and PEG and lower temperatures, with a clear inhibitory effect of mucilage.

Conclusions

The study has shown that the mucilage of H. deserti may act as a physical barrier for regulating diffusion of water and oxygen to the inner tissue of the seed and thereby prevent germination under unsuitable conditions.     

Seed dormancy and germination in Dodonaea viscosa (Sapindaceae) from south-western Saudi Arabia

Dodonaea viscosa (Sapindaceae) is widespread in the mountainous highlands of the southwestern part of Kingdom of Saudi Arabia, where it is a medicinally important species for the people in Saudi Arabia. Seeds of this species were collected from Mount Atharb in Al-Baha region, at an altitude of 2100 m. The aims of this study were to determine if the seeds of D. viscosa have physical dormancy (i.e. a water-impermeable seed coat) and, if so, what treatments would break dormancy, and what conditions promote germination after dormancy has been broken. The dormancy-breaking treatments included: soaking of seeds in concentrated sulfuric acid (H₂SO₄) for 10 min, immersion in boiling water for 10 min and exposure to 50 °C for 1 min. After seeds had been pre-treated with H₂SO₄, to break dormancy, they were incubated at constant temperatures from 5 to 35 °C, under 12-h photoperiods or in continuous darkness, and germination recorded. Salinity tolerance was investigated by incubating acid-scarified seeds in different concentrations of mM NaCl in the light at 25 °C.Untreated seeds had low final germination 30%. Seeds that had been acid-scarified, immersed in boiling water or exposed to 50 °C all achieved 91% subsequently when incubated at 25 °C. Thus, seeds of this species in Saudi Arabia have physical dormancy, which can be broken by all three treatments designed to increase the permeability of the testa. After pre-treatment, there was a broad optimum constant temperature for germination that ranged between 5 and 25 °C but germination was inhibited by higher temperatures (30 and 35 °C). Light had little effect on this germination response. Scarified seeds were also sensitive to salinity, with the highest germination in distilled water and complete inhibition in 400 mM NaCl. Seeds that failed to germinate in saline treatments were mostly able to germinate on transfer to distilled water, suggesting osmotic inhibition.     

The promotive effect on subsequent germination of treating imbibed celery seeds with high temperature before or during drying

Abstract High temperature (32°C) prevented germination of celery seeds even if given after 4 d of germination induction at 17°C in white light, but germination occurred if the seeds were then returned to 17°C. Celery seeds incubated for 3 d at 17°C in white light and then air-dried at 20°C germinated slowly when re-sown at 17°C in the light, achieving only 24% germination after 21 d. Exposure of such seeds to 32°C prior to and during drying resulted in 50% germination after 3.6 d at 17°C in white light, with no loss in viability, compared to 5.7 d for seeds not given a germination induction treatment. If celery seeds were dried rapidly germination was poor, an effect which could be overcome by high temperature treatment. It is suggested that the mechanism which imposes dormancy at 32°C also conditions the seed to withstand desiccation damage.     

Seed germination responses to salinity and temperature in Limonium supinum (Plumbaginaceae), an endemic halophyte from Iberian Peninsula

Limonium supinum, a perennial herb with interest for the restoration and gardening of arid zones, is widely distributed in saline areas from southeastern Iberian Peninsula. Laboratory experiments were carried out to assess the effects of temperature and salinity on seed germination and on germination recovery from the effects of saline conditions after transfer to distilled water. Seed germination responses were determined over a four temperature regimes (20/10, 25/15, 30/20 and 35/25 °C; 12 h light/12 h dark photoperiod) and six salinities (0, 100, 150, 200, 400 and 600 mM NaCl). The higher germination percentages were obtained in non-saline conditions, under all temperature regimes. An alternating temperature of 20 °C light and 10 °C dark yielded the maximum germination for any saline concentration. Increase in salinity delayed the beginning and end of germination and reduced the final percentage of germination, which becomes completely inhibited at 600 mM NaCl. The adverse effect of salinity is reinforced by high temperatures (30/20 and 35/25 °C). The germination rate was also negatively affected by the increase in salinity and temperature. The final recovery percentages in high salt treatments were near 100%, indicating that exposure to high concentration of NaCl did not inhibit germination permanently.