植物幼苗原发性超弱光子成像的研究

采用光子计数成像系统（PIAS）对植物幼苗萌发过程的超弱发光进行观察。结果表明,自发光子长时间积累可形成二维图象;光子计数和采集图象均可得到植物体的自发发光;通过实验探测到幼苗的根,叶在同一平面图象有不同的发光表现;光子成像系统可客观地比较生物自发超弱发光,为进一步研究超弱发光机理提供实验基础。     

水稻根的负负光性（简报）

萌发的水稻种子,用金属丝固定后,排放在透光盛水容器的水面,从单侧方向给种子照光,稻种长出的种子根和次生根均向背光一侧倾斜生长,负向光倾斜角度一般在25°～40°之间,少数可接近45°.感受光的部位和发生倾斜生长的部位均在根尖.根的倾斜生长角度受连续强光促进,而根的生长量则受强光抑制.     

水稻种子内生细菌研究进展

水稻的根、茎、叶、种子等器官存在大量对植株生长和产量、品质、抗性等有重要作用的共生和伴生微生物,其中内生菌是种子共生和伴生微生物中的一个代表类群.水稻种子中普遍存在种类丰富且结构复杂的内生菌群落,会直接或间接地影响种子的萌发、生长和群体的产量特性.从水稻种子内生细菌的多样性、水稻种子与其内生细菌分布的相关性、水稻种子内...     

脱落酸对水稻种子萌发及相关基因表达的影响

植物激素脱落酸(abscisic acid,ABA)调控着植物发育过程中的许多重要事件。实验以水稻(嘉育948)种子为材料,通过3种不同的外源ABA处理方法,观察萌发过程中根和芽的生长变化。结果表明,外源ABA对水稻种子的萌发率没有明显的影响,而对种子萌发过程中根和芽的生长速率具有显著的抑制作用(1A3A和1N3A);外源ABA对种子萌发过程中的抑制作用可部分逆转和恢复(1A3N);种子在低浓度的ABA中浸泡1d后再萌发,对根的生长有轻微的促进(1A3N)。通过RT-PCR和Northern杂交分析了水稻促有丝分裂原蛋白激酶5(OsMAPK5)、水稻酪蛋白激酶I1(OsCKI1)和β-葡糖苷酶2(BGLU2)3个基因在水稻种子萌发过程中(1A3A)转录水平上的表达差异,发现ABA抑制了这3个基因的表达,同时也影响了它们在根和芽中的表达模式。     

外源多胺对水稻萌发和前期生长的作用及其在土壤中的滞留

研究了不同浓度的多胺（尸胺、腐胺和亚精胺）对水稻种子萌发幼苗生长的化感作用结果表明．外源多肢对水稻种子萌发和幼苗生长均有抑制作用,尤其是对根的抑制,其作用程度依次为亚精胺＞腐胺＞尸胺,但是外源多胺能显著地提高水稻幼苗的抗冷性．使用灭菌土壤和用蒸馏水、Ｎａ２ＥＤＴＡ和盐酸水溶液浸取的实验结果表明,尸胺进入土壤后,大部分被土壤吸附和络合而滞留,少部分自由存于土壤中,在络合剂和酸存在下,尸胺可从土壤中解脱     

镧浸种对水稻种子萌发及幼苗生长的影响

以水稻种子为材料,研究了稀土元素镧对水稻种子活力和幼苗生长的影响。结果表明,1~20mg.L-1La3+处理能提高水稻种子的活力,提高蛋白酶、淀粉酶和脂肪酶的活性,并能促进水稻茎、叶和根系的生长,其中10mg.L-1La3+处理效果最佳。当浓度超过30mg.L-1时,水稻种子萌发和幼苗生长受到抑制。此外,镧对水稻植株地下部分(根系)生长的影响比地上部分(茎叶)生长的影响要明显。镧对水稻种子萌发期间3种酶活性的影响程度表现为蛋白酶>脂肪酶>淀粉酶。     

氧和二氧化碳对水稻萌发的影响

已知水稻种子具有无氧呼吸系统。早期的许多研究,都证明水稻种子在低氧分压甚至完全缺氧环境中依然可以萌发。但人们也可以观察到吸水后的水稻种子在一定的密闭环境中又缺少萌动发芽能力,可以预计,影响水稻种子萌发生长是和缺氧下酵解释放高浓度二氧化碳密切相关。过去的一些报告,着重研究缺氧对水稻幼苗生长的影响,而对自然界中常遇到的低氧所伴随产生高浓度二氧化碳环境下的种子萌发,却研究较     

过氧化氢对镉胁迫下水稻种子萌发的缓解效应

为了探讨外源H_2O_2对镉胁迫下水稻种子萌发受抑的缓解作用,以水稻品种‘中优169’为材料,通过培养皿滤纸发芽法,研究不同浓度H_2O_2对200μmol·L~(-1)镉胁迫下水稻种子萌发、幼苗生长及相关生理指标的影响。结果表明,在200μmol·L~(-1)镉胁迫下,水稻种子的萌发和幼苗生长表现出明显的抑制现象,发芽势、发芽指数、活力指数及幼苗的根长、芽长和可溶性蛋白含量均显著降低,MDA含量显著增加,POD活性上升,SOD、APX及CAT的活性显著受到抑制。较低浓度(≤10μmol·L~(-1))H_2O_2处理能不同程度地增加幼苗的根长、芽长、根鲜重和芽鲜重,提高镉胁迫下水稻种子的发芽指数和活力指数,增强SOD、POD和APX活性并降低MDA含量,从而缓解镉的毒害效应。其中5μmol·L~(-1) H_2O_2浸种处理对镉胁迫下水稻种子萌发和幼苗生长的缓解作用最好。高H_2O_2浓度对镉胁迫的缓解作用逐渐减弱,当H_2O_2浓度达到50μmol·L~(-1)时,会加重镉胁迫的毒性。表明适宜浓度的H_2O_2可以提高水稻幼苗抗氧化能力,缓解镉胁迫伤害。     

稀土元素─—硝酸铈对非洲紫罗兰和似马蹄莲组培苗生长的效应(简报)

在植物组织培养中，一定浓度的硝酸铈具有增加根数、促进根生长、刺激芽萌发和芽生长的作用。     

新型抗真菌活性物质农抗N2粗提物对水稻种子萌发的影响

为探究不同浓度新型广谱农抗N2粗提物对水稻种子萌发的影响及作用机制,采用紫外-可见分光光度法考察了农抗N2粗提物浸种对水稻种子多项萌发指标、淀粉酶活力、可溶性总糖、可溶性蛋白及丙二醛含量的影响。结果表明:农抗N2粗提物对水稻种子萌发的作用主要表现为低浓度促进,高浓度抑制。0.23-1.15μg/m L农抗N2粗提物浸种均能有效增强种子活力,促进胚芽和胚根的生长,尤以0.58μg/m L处理组效果最佳;此外,淀粉酶总活力、可溶性总糖和蛋白质含量相较CK分别提高了28.27%、7.73%与6.49%,且差异显著;同时,相比CK处理组,农抗N2粗提物浸种能显著降低种子中丙二醛的含量。因此,适宜浓度农抗N2粗提物浸种有利于促进水稻种子萌发,提高物质代谢能力,增强水稻种子的渗透调节与组织保护能力。     

Thermal Hardening: A New Seed Vigor Enhancement Tool in Rice

In a laboratory study, indica and japonica rice (Oryza sativa L.) seeds were exposed to thermal hardening (heating followed by chilling followed by heating; chilling followed by heating followed by chilling; heating followed by chilling or chilling followed by heating). In indica rice, heating followed by chilling followed by heating resulted in decreased mean germination time, time to start germination, electrical conductivity of seed leachates, and time to 50% germination, as well as increased germination index, energy of germination, radicle and plumule length, root length, root/shoot ratio, root fresh and dry weight, radicle and plumule growth rate, and shoot fresh weight. In japonica rice, chilling followed by heating followed by chilling performed better than all other treatments, including control.     

Thermal Hardening： A New Seed Vigor Enhancement Tool in Rice

In a laboratory study, indica and japonica rice (Oryza sativa L.) seeds were exposed to thermal hardening (heating followed by chilling followed by heating; chilling followed by heating followed by chilling; heating followed by chilling or chilling followed by heating). In indica rice, heating followed by chilling followed by heating resulted in decreased mean germination time, time to start germination, electrical conductivity of seed leachates, and time to 50% germination, as well as increased germination index, energy of germination, radicle and plumule length, root length, root/shoot ratio, root fresh and dry weight, radicle and plumule growth rate, and shoot fresh weight. In japonica rice, chilling followed by heating followed by chilling performed better than all other treatments, including control.     

短命植物独行菜种子萌发过程对低温的耐受特性

以独行菜（Lepidium apetalum）为材料,研究了其种子在萌发过程中耐受低温的特性,并对耐受低温的机制作了初步的探讨。结果表明：1.萌发至I、II、III期的独行菜种子经过冷诱导处理后,对零下低温-5℃、-10℃胁迫具有较强的耐受性,这种耐受性随萌发发展相对有所降低。2.独行菜种子萌发过程中胚根生长速度明显受到低温抑制,但也仍然能够生长。3.适当时间的低温层积能使独行菜萌发势显著提高,对终萌发率影响不大;过长时间的低温层积会使独行菜种子萌发势和最终萌发率降低。4.独行菜种子在4℃条件下不能萌发,但4℃层积2d的种子经25℃处理6h以上后,可耐受4℃低温而萌发,且萌发率随25℃处理时间增加而升高。如果25℃处理时间少于5h则不能在4℃低温下萌发。经4℃层积10d、再经25℃萌发处理1h的独行菜种子就能在4℃低温下萌发。综合分析认为独行菜种子不能耐受4℃低温萌发,原因可能是在露白前存在一个关键的生理阶段,在4℃胁迫逆境中不能越过这个阶段,该阶段之前与之后的萌发过程都能耐受4℃低温,因此对低温胁迫有良好的耐受性。这为探索早春短命植物耐受低温萌发的机制提供了新的思路。     

The Characteristics of Low Temperature Tolerance during Seed Germination of the Ephemeral Plant Lepidium apetalum (Cruciferae)

Lepidium apetalum was used to explore the characteristics and mechanismes of low temperature tolerance during seed germination. The results showed that pre treatment the seeds at 4℃ would improve the seeds viability after stressed by low temperature at -5℃ and -10℃ and the capability of seeds tolerance to cold temperature became weaker along with germination development. Although the growth of radicle was inhibited significantly at 4℃ during germination, the seeds could still survive and grow. With appropriate time of stratified at 4℃, germination pace would be improved and germination rate would not change, while both of which decreased if stratification lasted too long. Moreover, Lapetalum seeds were very sensible to the temperature during germination. It showed no germination at 4℃, while if seeds were stratificated for 48 hours at 4℃ and subsequently treated with 25℃ for more than 6 hours, seeds would germinate at 4℃ and the germination rate increased with the time of 25℃ treatment prolonged. If treatment at 25℃ was less than 5 houes, it showed no germinating. In addition, seeds with stratification for 10 days following 1 h treatment at 25℃ could also germinated at 4℃. The present study indicated that some pivotal genes that related with a key physiological stage before the onset of radicle protrusion might inhibite at 4℃, which resulted in Lapetalum seed could not germinate at 4℃. Except that physiological stage, the Lapetalum seed had a strong tolerance to low temperature at other germination stages. This experiment provided a new way to explore the germination mechanism of ephemerals plants seeds at low temperature.     

Examination of common ragweed's (Ambrosia artemisiifolia L.) allelopathic effect on some weed species

In the last decades the importance of some weed species increased in Hungary. The common ragweed (Ambrosia artemisiifolia L.) also belongs to this group. The allelopathic effect of watery extract made from different plant parts of common ragweed (air dried leafy shoots, seeds) were studied on the germination and growth of some weed species. The extracts were prepared with tap water, chopped dry plant materials were added to water and 24 hours later the material was filtered. The germination took place in a Binder KBW type thermostat in dark. 25 seeds were put into one Petri-dish, adding 15 ml plant extract to each in four repeats. The timing of germination was checked in every two days and the rate of growth was estimated after a week, by counting the numbers of germinated seeds and measuring the length of the radicle and plumula. The measured data were statistically analysed and the effect of extracts on germinating ratio and seedling length were evaluated.     

铬胁迫对‘协优赣2号’水稻种子萌发的影响

以水稻‘协优赣2号’种子为材料,探讨不同浓度铬对其萌发的影响。结果表明：低浓度Cr6+（≤10 mg/L）对该水稻种子萌发没有抑制作用;当Cr6+浓度≥50 mg/L时对其萌发有显著抑制作用。Cr6+对该水稻种子的发芽率影响很小,但一定程度上延迟了发芽;Cr6+对胚根生长抑制作用最大。     

The effect of cold storing pre-germinated lettuce seeds on radicle development and seedling emergence

The effects on radicle development and seedling emergence of cold storing batches of pre-germinated lettuce seeds for up to 7 days at 0 or 2 °C were investigated in three experiments. Cold storage tended to delay emergence and increase its spread in time. Separate batches of pre-germinated seeds gave different mean radicle lengths and different patterns of emergence and it is likely that small differences in mean temperature during germination were responsible since the length of radicles after germination was linearly related to accumulated day-degrees during the germination period. This suggests that germinating seeds over a period during which a required number of day-degrees is accumulated may produce radicles of the same length for different sowings. The elongation of radicles during cold storage was also linearly related to accumulated day-degrees. At 2 °C it appeared that the longer radicles elongated faster than the smaller ones and this may account for cold storage tending to increase the spread of seedling emergence when the pre-germinated seeds were sown into compost.     

THE EFFECTS OF TEMPERATURE ON THE GERMINATION AND RADICLE GROWTH OF PHOTOSENSITIVE LETTUCE SEED

1. The time course of germination of Grand Rapids lettuce seedshas heen followed with different combinations of temperature(3°–35°) and irradiation (red or far-red light).For each set of conditions the following three parameters weredetermined: (i) the time required for half maximum germination,(ii) the rate of germination during the actively germinatingphase, and (iii) the maximum germination attained. In general,as the temperature was lowered, with dark-imbibed seeds, (i)became longer, (ii) became lower, but (iii) became progressivelyhigher. The effect of red light at any temperature was to shorten(i) and increase (ii) and (iii) over the values dark controls.Far-red light exerted an effect opposite to that of red light.Temperatures higher than 25° inhibited (ii) and (iii) underany light conditions. The optimum temperature to the actionof red and far-red light is 25°, at which the stimulatoryeffect of red light and the inhibition of this effect by far-redlight are both maximal. 2. The growth of the radicles of de-coated seeds of Grand Rapidslettuce shows two phases at all temperatures studied. PhaseI is characterized by slow but linear growth which continuesuntil shortly after visible differentiation of the radicle intothe hypocotyl and the root. Phase II is a phase of active growthin which the total length reflects mainly the length of theroot. The optimum temperature for Phase I is 25°-35°,and that, for Phase II is 25°. In neither phase, and atnone of the temperatures studied, is there any effect of redor far-red radiation on the growth of the radicle. The firstvisible sign of radicle elongation in red light induced seeds,however, takes place at exactly the same time as that of germination. 3. Similarities and dissimilarities between the germinationand the growth are pointed out, and it is concluded that thetwo phenomena are different, but proceed at sites closely associatedin the embryo. ¹Present address: Johnson Foundation for Medical Physics, Universityof Pennsylvania, Philadelphia, Pa., U.S.A.     

A water relations analysis of seed germination rates

Seed germination culminates in the initiation of embryo growth and the resumption of water uptake after imbibition. Previous applications of cell growth models to describe seed germination have focused on the inhibition of radicle growth rates at reduced water potential (Ψ). An alternative approach is presented, based upon the timing of radicle emergence, to characterize the relationship of seed germination rates to Ψ. Using only three parameters, a `hydrotime constant' and the mean and standard deviation in minimum or base Ψ among seeds in the population, germination time courses can be predicted at any Ψ, or normalized to a common time scale equal to that of seeds germinating in water. The rate of germination of lettuce (Lactuca sativa L. cv Empire) seeds, either intact or with the endosperm envelope cut, increased linearly with embryo turgor. The endosperm presented little physical resistance to radicle growth at the time of radicle emergence, but its presence markedly delayed germination. The length of the lag period after imbibition before radicle emergence is related to the time required for weakening of the endosperm, and not to the generation of additional turgor in the embryo. The rate of endosperm weakening is sensitive to Ψ or turgor.     

不同硬实程度乌拉尔甘草种子的活力差异

根据乌拉尔甘草种子吸胀时间的长短将种子硬实程度分为H0、H1、H2、H3、H4和Hmax6个等级,测定其活力指标;同时于盐胁迫和水分胁迫下测定硬实和非硬实种子的发芽率、发芽指数、胚根长度及幼苗的抗氧化酶活性。结果表明:随着硬实程度的增大,种子的发芽率、发芽指数、胚根长度、脱氢酶活性和ATP含量均呈上升趋势,丙二醛(MDA)含量则表现出下降趋势;在逆境条件下,硬实种子比非硬实种子的适应能力强。硬实种子的活力高于非硬实种子,硬实程度与种子活力呈正相关。