花粉的保存及其生活力测定

花粉是种子植物的雄配子体，在有性繁殖中发挥着重要作用。采集的花粉和贮存的花粉，在使用之前必须作生活力的鉴定，以估价花粉是否有授精能力，并掌握花粉的形态和生理特征。本文对花粉的采集与保存、花粉生活力的概念及花粉生活力的测定方法作了详细的介绍，并对各种方法的优缺点进行了讨论。     

植物胚胎学实验方法（一）：花粉生活力的测定

采集的花粉和经贮存的花粉,在使用之前必须作生活力的测定以鉴定其质量。测定花粉生活力的方法主要有三种。即离体萌发、活体萌发和用氧化还原染料的非萌发分析测定法。这里介绍三种经常用的和在短时间可以得到结果的方法:花粉离体萌发法,用氧化还原染料染色法和荧光素二醋酸脂的荧光方法。     

天女木兰花粉形态特征及其生活力

对天女木兰（Magnolia sieboldii）花粉的采集时期、形态以及培养的温度和培养基进行了研究,并探讨贮存温度和时间对花粉生活力的影响。结果表明,扫描电镜观察到的花粉形状和萌发孔与其他已报道的木兰科植物相同,但大小和花粉外壁的纹理不同。在花瓣刚刚展开的初花期采集的花粉生活力最高。25℃下最适于花粉的萌发;花粉在含10％蔗糖＋0．1％硼酸的培养基上培养14h的萌发率最高,0．01％～0．05％的氯化钙对花粉的萌发影响不显著,0．1％的氯化钙对花粉的萌发有抑制作用。随着贮存时间的延长,花粉萌发率不断降低。不同贮存温度下花粉萌发率的降低速度依次为-10℃〈4℃〈25℃,-10％下贮藏5d的花粉萌发率降低了48．8％,10d后萌发率降低为0。     

花粉的采集、贮藏和生活力的测定

花粉是高等植物的雄配子体,在有性繁殖中传递着雄性遗传物质。它既是研究植物遗传、育种、进化,生殖等的重要对象,也是孢粉分析、蜂群培育、药物制造、医疗及生理试验等的重要材料。本文在花粉采集、贮藏和测定生活力三方面作一些介绍。     

用“TTC”法(红四氮唑)测定小麦根和花粉的活力及其应用

在农业生产和科学试验中,常常会碰到需要测定植物种子、根以及花粉的生活力的问题。关于种子生活力的测定已有不少报导,但关于植物的根、花粉的生活力的测定及其应用却报导不多。现以“TTC”法测定冬小麦的根和花粉生活力为例,对它的测定方法和应用作一初浅介绍。“TTC”:(2.3.5-Triphenyl Tetrazolium Chloride)即2.3.5-氯化三苯基四氮唑;又     

水分胁迫对澳洲坚果花粉生活力和贮藏性的影响

采集经不同水分胁迫处理的澳洲坚果植株的花粉进行生活力测定和贮藏性研究,结果表明,新鲜花粉生活力随贮藏时间增加而下降。常温下正常发育花粉可保存6d左右,此后萌发率逐渐下降;而处于水分胁迫下的花粉,6d后生活力迅速降低;水分胁迫程度越严重,花粉生活力下降越快。几种处理的花粉有效贮藏期分别是:饱和灌溉处理6d,正常灌溉处理30d,水分亏缺处理10d,严重干旱处理(CK)4d。研究还表明,品种间花粉贮藏性表现为Kau >Pahala >O.C.。澳洲坚果花粉生活力的最佳染色鉴定方法为联苯胺染色法。     

春小麦花粉育株后代数量性状的遗传与变异的初步研究

关于花粉育株后代的遗传表现已有不少报道,有些作者在烟草、水稻等花粉育株的研究中指出,花粉育株后代的遗传性相对稳定。胡含等对小麦花粉育株后代作了较系统的研究,认为花粉育株的株系间表现多样性,而系内表现相对稳定性。对于花粉育株后代生活力是否衰退则有两种不同看法,有人在烟草等作物的花粉育株后代中观察到生活力衰退现象,而另一些作者在烟草、水稻、小麦等作物上没有看到生活力衰退现象。     

不同贮藏条件及生长调节剂对欧李花粉生活力的影响

以2年生欧李植株为试材,采用液体培养法研究了不同采集时间、贮藏时间、贮藏条件以及不同生长调节剂对欧李花粉萌发和花粉管生长的影响。结果表明:(1)欧李花粉在大花苞期至初花期的生活力和发芽力最强,是花粉适宜的采集时期。(2)贮藏条件对花粉的贮藏时间起决定作用,在干燥条件下,花粉的生活力迅速降低,在自然湿度条件下,欧李花粉的贮藏时间随温度的降低而延长,-89℃超低温是欧李花粉贮藏的适合条件。(3)6-BA对花粉的萌发有抑制作用,但适宜的浓度(15mg·L-1)可以促进花粉管的生长,反之则抑制花粉管的生长;所有浓度的2,4-D均能促进花粉管的生长,但浓度对花粉萌芽率的影响极大;低浓度NAA(<20mg·L-1)或GA3(<50mg·L-1)对欧李花粉的萌发和花粉管的生长均影响不大;当NAA≥20mg·L-1时,对花粉的萌发有抑制作用,对花粉管的生长有促进作用;当GA3≥50mg·L-1时对花粉萌发和花粉管生长均具有一定的抑制作用。     

拟南芥花粉活力的测定及其在花粉发育研究中的应用

花粉发育是植物生活周期中一个重要且复杂的过程, 需要多种基因的参与。花粉发育是否完善可以根据花粉形态特征, 并通过检测花粉的生活力、萌发力、可育性和受精能力等生理特征来判断。以拟南芥候选基因突变体为材料, 通过对花粉的这些生理特征的检测, 可以初步推测候选基因参与花粉发育的功能和作用机制。本文介绍了用于花粉活力测定的几种技术的原理和方法, 以及应用这些方法进行花粉发育研究的进展。     

拟南芥花粉活力的测定及其在花粉发育研究中的应用

花粉发育是植物生活周期中一个重要且复杂的过程,需要多种基因的参与。花粉发育是否完善可以根据花粉形态特征,并通过检测花粉的生活力、萌发力、可育性和受精能力等生理特征来判断。以拟南芥候选基因突变体为材料,通过对花粉的这些生理特征的检测,可以初步推测候选基因参与花粉发育的功能和作用机制。本文介绍了用于花粉活力测定的几种技术的原理和方法,以及应用这些方法进行花粉发育研究的进展。     

Pollinator preference and pollen viability mediated by flower color synergistically determine seed set in an Alpine annual herb

Gentiana leucomelaena manifests dramatic flower color polymorphism, with both blue‐ and white‐flowered individuals (pollinated by flies and bees) both within a population and on an individual plant. Previous studies of this species have shown that pollinator preference and flower temperature change as a function of flower color throughout the flowering season. However, few if any studies have explored the effects of flower color on both pollen viability (mediated by anther temperature) and pollinator preference on reproductive success (seed set) in a population or on individual plants over the course of the entire flowering season. Based on prior observations, we hypothesized that flower color affects both pollen viability (as a function of anther temperature) and pollen deposition (as a function of pollinator preference) to synergistically determine reproductive success during the peak of the flowering season. This hypothesis was tested by field observations and hand pollination experiments in a Tibetan alpine meadow. Generalized linear model and path analyses showed that pollen viability was determined by flower color, flowering season, and anther temperature. Anther temperature correlated positively with pollen viability during the peak of the early flowering season, but negatively affected pollen viability during the peak of the mid‐ to late flowering season. Pollen deposition was determined by flower color, flowering season (early, or mid‐ to late season), and pollen viability. Pollen viability and pollen deposition were affected by flower color that in turn affected seed set across the peak of the flowering season (i.e., when the greatest number of flowers were being pollinated). Hand pollination experiments showed that pollen viability and pollen deposition directly influenced seed set. These data collectively indicate that the preference of pollinators for flower color and pollen viability changed during the flowering season in a manner that optimizes successful reproduction in G. leucomelaena. This study is one of a few that have simultaneously considered the effects of both pollen viability and pollen deposition on reproductive success in the same population and on individual plants.     

Changes of pollen viability of ornamental plants after long-term preservation in a cryopreservation pollen bank

This study determined the changes in pollen viability of 102 species/cultivars of ornamental plants (affiliated to 32 genera of 14 families) following long-term liquid nitrogen storage in a cryopreservation pollen bank. The goal was to provide information on the safety and stability of pollen cryopreservation technology. Fresh pollen at the time of storage was used as the control, and the study examined the pollen viability of ornamental plants cryopreserved for 8, 9, or 10 years. The results show that pollen of the 102 species/cultivars in the cryopreservation pollen bank retained viability ranging from 1% to 58%, After long-term storage there were changes in viability: 11.76% (12 species/cultivars) had increased viability, 16.67% (17 species/cultivars) had stable viability, and the viability of 71.57% (73 species/cultivars) showed a decreasing trend.     

Viability and sunlight sensitivity of oak pollen and its implications for pollen-mediated gene flow

Pollen-mediated gene flow and the male reproductive success of wind-pollinated trees depend on the initial viability of the pollen and the changes that occur in its viability during transport in the atmosphere. The viability of Quercus robur pollen was determined before and during exposure to sunlight by in vitro germination and the fluorescein diacetate reaction (FCR) in 2002 and 2003, respectively. These experiments allowed us to calculate initial pollen viability and pollen sensitivity to sunlight. The germination test revealed a lower initial pollen viability (25–65%) than the FCR (53–92%). Following 9.5 h of irradiation the viability was reduced to 75–100% as determined by the in vitro germination test or to 40–70% as determined by the FCR. The actual values of initial pollen viability and pollen sensitivity to sunlight were used to define a range of values for modelling pollen dispersal using the mesoscale meteorological model METRAS. The deposition patterns of viable pollen varied by as much as a factor of 14 by changing the viability parameters in the range of the observed values. This suggests significant differences in male reproductive success. Variations in initial pollen viability have stronger effects on the gene-flow pattern than do variations in pollen sensitivity to sunlight. In particular, pollen distribution throughout the local environment is shaped by the initial pollen viability, while pollen sensitivity to sunlight mainly influences long-distance pollen dispersal.This revised version was published online in February 2005 with corrections to an incorrect sentence in the Results section. Under Pollen Sensitivity it should read: decreased faster when assessed by the germination test than by the FCR.     

银杉花粉生命力及其变异

中国特有植物银杉(Cathay argyrophylla)是最濒危的松杉类植物之一。研究表明,受精前胚珠的高败育率是银杉生殖效率低的重要原因之一,但迄今对银杉花粉活力及其变异仍不得而知。由于花粉活力对授粉、受精、种子产量和质量以及后代适合度都有直接影响,该研究采用TTC染色和体外萌发法测定了来自大瑶山(Dayaoshan, DYS)和花坪(Huaping, HP)两个地区7个种群16个个体52份银杉花粉样品的生活力。结果表明银杉花粉的活力水平(93.3%)与其它裸子植物相当,干燥低温条件下银杉的花粉活力比较稳定,体外萌发的适宜蔗糖浓度在13%左右。ANOVA分析揭示种群内个体间的花粉活力差异不大(p>0.05),而地区内的种群间及地区间的花粉活力有显著差异(p<0.05)。银杉花粉活力与其生殖成功没有相关性。在上述基础上,从控制授粉的角度讨论了银杉的保护策略和复壮的可能性。     

DNA uptake during electroporation of germinating pollen grains

Electroporation of germinating pollen grains of Nicotiana gossei (L.) Domin under a variety of conditions showed that DNA was taken up by the pollen without detrimental effects on the viability of the pollen. By optimizing both the field strength of the electroporation pulse and the DNA concentration in the electroporation medium up to 6% of the donor DNA can be taken up by the germinating pollen while maintaining a pollen viability of 90%. Field strengths as high as 9 kV/cm could be applied to germinating pollen grains without detrimental effects on viability. Southern hybridizations demonstrated that DNA encoding the marker enzyme β-glucuronidase (GUS) was incorporated into electroporated pollen. Germinating pollen, treated in this manner, is capable of producing 300–400 seeds per capsule of viable seed when applied to the stigmas of compatible flowers of N. gossei which has been emasculated 4 days earlier.     

Pollen viability and pollen vigor

Summary Investigations were carried out to correlate pollen viability, assessed on the basis of a fluorochromatic reaction (FCR) test, with pollen vigor, assessed on the basis of the time taken for in vitro germination in pollen grains subjected to high humidity (>95% RH) and temperature (38 °C) or storage stress of Nicotiana tabacum, Agave sp., Tradescantia virginiana, and Iris sp. Both high RH and temperature, as well as storage stresses, affected pollen vigor before affecting pollen viability. The results are discussed in the light of available data on the viability and vigor of stressed pollen and of aged seeds. The need for consideration of pollen vigor, particularly in stored pollen, the inadequacy of the methods presently used, and some of the methods suitable to assess pollen vigor are elaborated.     

Viability and longevity of pollen from transgenic and nontransgenic tall fescue (Festuca arundinacea) (Poaceae) plants

Pollen is an important vector of gene flow in plants, particularly for outcrossing species like tall fescue. Several aspects of pollination biology were investigated using pollen from transgenic and nontransgenic plants of tall fescue (Festuca arundinacea Schreb.), the most important forage species worldwide of the Festuca genus. To effectively assess in vitro pollen viability in tall fescue, an optimized germination medium (0.8 mol/L sucrose, 1.28 mmol/L boric acid and 1.27 mmol/L calcium nitrate) was developed. Treatment with relatively high temperatures (36° and 40°C) and high doses of UV-B irradiation (900-1500 μW/cm(2)) reduced pollen viability, while relative humidity did not significantly influence pollen viability. Viability of pollen from transgenic progenies (T1 and T2) was similar to that from seed-derived control plants. Pollen from primary transgenics (T0) and primary regenerants (R0) had various levels of viability. Hand pollination using the primary regenerants and transgenics revealed that no seed set could be obtained when pollen viability was lower than 5%. Pollen from transgenic progenies and nontransgenic control plants could survive up to 22 h under controlled conditions in growth chamber. However, under sunny atmospheric conditions, viability of transgenic and nontransgenic pollen reduced to 5% in 30 min, with a complete loss of viability in 90 min. Under cloudy atmospheric conditions, pollen remained viable up to 240 min, with about 5% viability after 150 min. This report is the first on pollen viability and longevity in transgenic forage grasses and could be useful for risk assessment of transgenic plants.     

Effect of Water Loss on Germination Ability of Maize (Zea mays L.) Pollen

The correlation between water content and viability of maizepollen grains was studied on the basis of the germination abilityof pollen from a single cross hybrid. There was found to beclose correlation between viability of the grains and theirtolerance to desiccation. Most of the pollen grains in the hybridexamined survived a reduction by almost 50 per cent of the originalwater content without loss of normal function. With water lossgreater than this, less vigorous pollen grains died or losttheir ability to form pollen tubes. Consequently, when pollinationwas carried out using pollen with a water content reduced bymore than 50 per cent, only the most tolerant pollen grainssurvived to take part in the competition which precedes fertilization.Dry pollen grains required a longer period to establish adhesionto the stigma surface and to initiate pollen tubes than pollengrains with higher water content, but otherwise their behaviourwas normal. If more than 80 per cent of the original water contentwas lost, disturbances occurred in the physiology of the grainssurviving the treatment. This was exhibited as death or a reductionin rate of pollen tube growth. Drying of pollen by an amount which does not irreversibly damagethe more tolerant grains could possibly be used as a means ofpollen selection. Zea mays L., maize, pollen viability, pollen treatment, dehydration, pollen tube     

不同贮藏温度下大别山五针松花粉活力的变化

大别山五针松( Pinus dabeshanensis C. Y. Cheng et Y. W. Law)为松科( Pinaceae)松属( Pinus Linn.)植物,自然种群数量极少,目前仅发现在安徽省岳西县大王沟海拔900~1300 m阴坡和半阴坡有相对集中的分布,种群规模计200余株,且多为成年个体,林下幼苗极少,自然更新困难,为中国特有珍稀树种之一[1]。大别山五针松常在每年3月份至4月份形成花芽,5月中下旬花粉成熟并散发,花粉具气囊,此时雌球花张开接受传粉,球果翌年9月成熟[2]。据作者近年的调查,大别山五针松种子败育率较高,且种子质量较低,这也是该种类濒危的重要原因之一。