越南篦齿苏铁传粉媒介的研究

利用排除法和引入昆虫的方法相结合,研究越南篦齿苏铁(Cycas elongata)的传粉媒介.结果表明,越南篦齿苏铁靠风媒传粉和虫媒传粉的雌株结实率分别55.3%和57.2%,自然传粉的结实率为63.5%,说明风和象鼻虫都是越南篦齿苏铁的有效传粉媒介.越南篦齿苏铁散粉高峰在白天,夜间散粉很少,在3.0 m以内风传花粉的密度较高,3.0 m之外的密度急剧下降.可见,风媒和虫媒都是越南篦齿苏铁的有效传粉途径,与泽米铁类植物为专一寄主性昆虫传粉的结论不一致.     

杜鹃红山茶花粉萌发力及贮藏耐性的研究

以2～3年生嫁接的杜鹃红山茶(Camellia azalea)花粉为实验材料,研究了不同培养基、不同培养温度对其萌发的影响,同时探讨了不同贮藏条件和贮藏时间下花粉生活力的差异。结果表明:杜鹃红山茶花粉在不同培养时间下其萌发率呈抛物线型,花粉在15%蔗糖+0.02%硼酸的培养基上萌发率最高,30℃的培养温度比25℃、20℃更适合杜鹃红山茶花粉萌发。-20℃冷冻保存和液氮保存都是适合杜鹃红山茶花粉长期保存的方式。     

二乔玉兰花粉贮存条件的比较研究

探讨了二乔玉兰(MagnoliasoulangeanaSoul.-Bod.)花粉在不同温度和贮存条件下的活力。结果表明:二乔玉兰花粉在5%蔗糖 0.01%硼酸及5%蔗糖 0.1%硼酸两种培养液上萌发较好,萌发率均达到70%以上。随着保存时间的延长,花粉萌发率不断降低,降低速度从快到慢依次为室温、5℃和-20℃。超低温(-196℃)保存花粉的萌发率并没有随着保存时间的延长而降低,液氮保存2a的花粉萌发率达到79.3%,与新鲜花粉的萌发率差异不显著。超低温反复冻存6次的花粉萌发率与新鲜花粉没有显著变化。     

三种苏铁植物呈现出迥异的水力安全边界北大核心CSCD

为探究苏铁植物的水力安全边界(hydraulic safety margins,HSM),该试验选用经典的自然干燥法和最新发表的抽气法测定三种同质园苏铁植物抗旱性(即叶轴木质部脆弱性曲线),获得抗旱指标P_(50)和P_(88)(导水率丧失或气体抽取量分别为50%和88%时的木质部水势),与叶片正午水势计算HSM,结合管胞性状分析。结果表明:(1)苏铁(Cycas revoluta)、越南篦齿苏铁(C.elongata)、摩瑞大泽米苏铁(Macrozamia moorei)的管胞长度分别为(4413±378)、(5146±730)、(6954±862)μm,苏铁、越南篦齿苏铁与摩瑞大泽米苏铁差异显著(P<0.05)。(2)两种方法测定的脆弱性曲线都呈典型的“S”型,苏铁、越南篦齿苏铁、摩瑞大泽米苏铁的P_(50H)(导水率丧失50%时的木质部水势)和P_(50P)(气体抽取量为50%时的木质部水势)分别为-2.5、(-2.4±0.5)MPa,-2.3、(-3.6±0.7)MPa,-1.5、(-1.8±0.2)MPa,在已发表的裸子植物数值范围内。P_(50)和P_(88)具有显著一致性(除了越南篦齿苏铁的P_(50P)比P_(50H)更低,表示更强抗旱性),与已发表的其他木质部管胞物种通过水力学法和抽气法获得的P_(50)和P_(88)比较分析,具有显著相关性(R^(2)=0.72,P=0.0081;R^(2)=0.87,P=0.0007)。(3)自然干燥法和抽气法计算的HSMs具有相同的趋势,摩瑞大泽米苏铁为负值,而苏铁和越南篦齿苏铁为正值。综上所述,三种苏铁植物的抗旱性均在已发表的裸子植物范围内,两种方法都适于测定木质部管胞结构的苏铁类植物脆弱性曲线,苏铁、越南篦齿苏铁与摩瑞大泽米苏铁具有不同的水力安全边界。利用脆弱性曲线和正午水势探讨苏铁植物的水力安全边界,为苏铁植物的水分监测、管理和保育提供依据。     

福建苏铁调查研究初报

对福建苏铁经过三年多的调查、观察和研究,基本完成福建苏铁原产地的调查,认为福建原产两种苏铁,即苏铁与四川苏铁。本文还对福州树木园引种栽培的苏铁进行分类研究,有苏铁、四川苏铁、海南苏铁、攀枝花苏铁、广东苏铁、台东苏铁、元江苏铁、暹罗苏铁、石山苏铁、篦齿苏铁、越南苏铁、叉叶苏铁、多羽叉叶苏铁、多歧苏铁、刺叶苏铁等,另有三种形态特征比较特殊的苏铁也在本文进行了简要描述。     

福建苏铁调查研究初报

对福建苏铁经过三年多的调查、观察和研究 ,基本完成福建苏铁原产地的调查 ,认为福建原产两种苏铁 ,即苏铁与四川苏铁。本文还对福州树木园引种栽培的苏铁进行分类研究 ,有苏铁、四川苏铁、海南苏铁、攀枝花苏铁、广东苏铁、台东苏铁、元江苏铁、暹罗苏铁、石山苏铁、篦齿苏铁、越南苏铁、叉叶苏铁、多羽叉叶苏铁、多歧苏铁、刺叶苏铁等 ,另有三种形态特征比较特殊的苏铁也在本文进行了简要描述。     

八种苏铁植物叶轴的比较解剖研究

对苏铁科和泽米铁科8种苏铁植物,即台湾苏铁(Cycas taiwaniana)、海南苏铁(C·hainanensis)、元江苏铁(C·parvulus)、单羽苏铁(C·simplicipinna)、滇南苏铁(C·diannanensis)、越南篦齿苏铁(C·elon-gata)、长刺大泽米铁(Macrozamia longispina)、双子铁(Dioon edule)的叶轴横切面结构进行了比较研究,以期为苏铁植物的系统演化和分类进一步提供解剖学依据,并探讨其解剖结构与生态的适应机制。结果表明,较原始的苏铁科和较进化的泽米铁科叶轴的横切面结构无论在表皮、机械组织、基本组织和维管组织,还是在后含物方面都存在着明显的不同;泽米铁科的大泽米铁属与双子铁属差异也较大;苏铁科科内的6个种则相似性稍大,表明它们是亲缘关系较密切的类群,但每个种都有各自的结构特点。越南篦齿苏铁的维管束排列方式和数目的增加方式与泽米铁科两个种的相似,因此推断它处于较进化的地位。研究还发现苏铁科种类的叶轴的近轴面均像叶片那样具有栅栏组织状同化组织存在。苏铁类植物叶轴具有旱生植物的解剖结构特征:角质层较厚、表皮细胞壁厚、机械组织发达、晶体较多、分泌道和维管束数目较多等结构特征。这些对研究苏铁纲各科及种类之间的进化与亲缘关系提供了佐证,同时揭示了苏铁纲这类古老的植物类群其多个属的种类能够经历如此漫长的地质年代而幸存下来,是由于其在长期演化过程中均形成了这些独特的结构特征,因而具备了相对应的生理功能,能够在恶劣的自然环境下,具备耐干旱、贫瘠、高温及耐盐碱等逆境的结果。     

培养基组分、激素及pH值对转基因白桦花粉萌发的影响

采用花粉离体培养法研究了培养基不同组分、激素及pH值对转基因白桦（Betula platyphylla Suk.）花粉萌发的影响。结果表明,培养基组分在一定范围内促进花粉萌发,转基因白桦花粉萌发对硼酸和Ca^2＋的反应敏感,培养基中缺乏该物质时花粉不萌发。激素类物质低浓度时促进萌发,高浓度时抑制萌发。最适合培养基组分为蔗糖18%,硼酸0.015%,Ca^2＋ 0.020%,pH6.0,NAA 10mg/ml,6-BA 1mg/ml。并对不同保存条件（4℃,-20℃）下转基因白桦花粉的萌发率进行了比较,4℃下干燥保存更有利于保持转基因白桦花粉的活力。     

培养条件及贮藏温度和时间对木麻黄花粉萌发率的影响

用离体培养的方法研究了不同蔗糖、硼酸浓度,以及不同贮藏温度和贮藏时间对木麻黄(Casuarina)花粉萌发的影响.结果表明:15%的蔗糖是木麻黄花粉萌发的最佳浓度;在15%蔗糖培养基上添加硼酸显著促进木麻黄花粉萌发,250 mg kg-1硼酸是木麻黄花粉萌发的最佳浓度;添加了琼脂的固体培养基更有利于木麻黄花粉萌发;在常温下木麻黄生活力丧失很快,但低温下花粉的萌发力可保持较长时间.     

金银忍冬花粉离体萌发初探

以金银忍冬[Loniceramaackü(Rupr.)Maxim.]为试材,研究了不同种类糖、硼酸、钙离子、pH值、光照等单因子对花粉萌发的影响.结果表明,培养基中分别含有25%的蔗糖、0.01%的硼离子、0.02%～0.05%的钙离子以及pH6.7时较适合金银忍冬的花粉萌发,萌发率分别为85.63%、59.23%、78.12%和75.27%;培养基中不同种类的糖对花粉萌发的影响不同,以乳糖最适宜,其次是葡萄糖、蔗糖和果糖;在光照(0.5625 μmol m-2s-1)与黑暗下培养,金银忍冬花粉的萌发率没有明显的变化,但黑暗条件更利于花粉管的生长.金银忍冬花粉在含有25%蔗糖、0.01%硼离子、0.02%钙离子、pH为6.7的培养基上光照培养3 d,其花粉萌发率均达到80%以上,最高的萌发率可达88.1%.     

Histological and Morphological Studies of Pollen Grains from Elongata, Reduced Elongata and Staminate Flowers in Carica papaya L.

The quality and quantity of pollen from three types of flowers; elongata, reduced elongata and staminate from the commercialized Thai papaya cultivar ‘Khak Nual’ were determined using pollen morphology, pollen physical characters and pollen development processes. Pollen development progressed at the same pace in the three types of pollen-producing flowers and was consistent with pollen development in many angiosperms. Pollen morphology showed that papaya pollen grains are tricolporate, with three apertures, and there is no significant difference in diameter (25.18–25.72 μm) and weight (11.76–15.45 ng) among pollen sources. The staminate flower shows the lowest amount of pollen, with 12,368 pollen per anther, but higher viability and germination rates of 95.53 % and 53.64 %, respectively. In contrast, the elongata type shows the highest amount of pollen grains with 14,884 pollen per anther and the lowest viability and germination rates, 93.06 % and 46.33 % respectively. The physical characteristics of pollen grains from reduced elongate and elongate flowers are similar. Reduced elongate flower type can donate pollen without self-pollinating.     

小果短柱茶花粉离体培养系统的研究

山茶的短柱茶组是优良种质资源,有必要对小果短柱茶(Camellia confusa Chang 1941)的花粉萌发和花粉管生长的生理特性进行研究.本文研究了花粉生活力、培养温度及pH对小果短柱茶花粉萌发和花粉管生长的影响.结果表明:最适离体萌发培养基为5%蔗糖、0.003%的硼酸,0.005%的氯化钙和12%的PEG...     

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.     

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。     

Storage of Pollen Grains in Organic Solvents: Effect of Organic Solvents on Leaching of Phospholipids and its Relationship to Pollen Viability

In vitro germinability and membrane integrity (as revealed bythe fluorochromatic reaction (FCR) test) of pollen grains ofCrotalaria retusa L. stored in various organic solvents forsix months at –20±2 °C were studied and correlatedwith leaching of lipids, phospholipids, sugars and free aminoacids from pollen grains into organic solvents during storage.Pollen grains stored in organic solvents with low dielectricconstants (a measure of their non-polar nature), such as hexane,cyclohexane and diethyl ether, showed high scores for germinationand FCR and very little leaching of phospholipids, sugars andamino acids. Pollen grains stored in solvents with high dielectricconstants (a measure of their polar nature) such as isopropanoland methanol did not show germination or positive FCR scores,but showed extensive leaching of phospholipids, sugars and freeamino acids. The viability of pollen grains stored in organicsolvents seems to be determined largely by the effect of theorganic solvents on pollen phospholipid composition, which inturn affects membrane integrity and consequently pollen viability. Crotalaria retusa, organic solvents, pollen storage, viability, phospholipids     

Loss of viability of tomato pollen during long-term dry storage is associated with reduced capacity for translating polyamine biosynthetic enzyme genes after rehydration

The possibility that a loss of pollen viability during dry storage in a freezer is caused by the reduced pollen capacity to enhance polyamine biosynthetic enzyme activity after rehydration was investigated using pollen grains of tomato (Solanum lycopersicum=Lycopersicon esculentum) stored at -30 degrees C under dry conditions for up to 42 months. Pollen grains showed normal germinability for at least 12 months in storage, but those stored for longer than 24 months exhibited a significant reduction in germinability and fruit-setting ability. This age-dependent reduction in pollen viability coincided with the extent to which the pollen lost the capacity to increase arginine decarboxylase (ADC) and S-adenosylmethionine decarboxylase (SAMDC) activities and polyamine contents upon rehydration. Immunoblot analysis indicated that the capacity of pollen to translate ADC and SAMDC mRNAs was impaired in accordance with the loss of viability. Also, the capacity to synthesize proteins in general decreased with the increase in storage duration. The addition of 1 mM putrescine, spermidine, or spermine to incubation medium promoted germination, impregnation of pollen grains with 1 mM spermidine restored fertilization ability, and the addition of 1 mM spermidine to incubation medium promoted protein synthesis exclusively in pollen grains which had been stored for a long time. These results indicate that the reduction in viability of tomato pollen during long-term dry storage in a freezer involves a decline in the capacity to enhance gene translation for polyamine biosynthetic enzymes upon rehydration.     

Evaluation of Viability,Shedding Pattern,and Longevity of Pollen from Genetically Modified (GM) Herbicide-tolerant and Wild-type Zoysiagrass (<Emphasis Type="Italic">Zoysia japonica</Emphasis> Steud.)

Knowledge about pollen viability is important when evaluating the risk of genetically modified (GM) plants. Here, staining via iodine potassium iodide (IKI) or triphenyl tetrazolium chloride (TTC) could not distinguish between live and dead pollen from Zoysia japonica. Therefore, to obtain a reliable assessment of such viability and longevity, we developed an optimum germination medium containing 20% sucrose and 50 ppm H₃BO₃. Pollen grains transferred to the germination medium at about 1000 hours had a germination rate of >90%. Pollen was most predominantly shed at approximately 1000 hours, with viability declining to nearly 0% at 1200 hours. All germinability was lost within 150 min when stored at 25°C. No significant difference was found between GM and non-GM plants in their pollen viability or longevity.     

Storage in an Organic Solvent as a Means for Preserving Viability of Pollen Grains

Pollen grains of Lilium auratum, Lilium longiflorum, Camellia sasanqua and Impatiens balsamina were soaked in various kinds of organic solvents such as acetone, benzene, petroleum benzine, benzyl alcohol, butanol, ethanol, methanol, isopropanol, diethyl ether, petroleum ether and choroform, and stored at 4-6 C for 24 hr. All pollen grains except in benzyl alcohol showed evidence of viability, and grains which had been stored in acetone, benzene, petroleum benzine, diethyl ether, petroleum ether and chloroform produced longer pollen tubes than grains of fresh pollen, especially Camellia sasanqua, whose pollen grew tubes 3 times as long as those of a control. Lilium auratum pollen grains had retained their viability after 80 days in acetone, benzene, petroleum benzine, diethyl ether and petroleum ether, and generative nuclei in pollen thus stored divided to form 2 sperm nuclei in artificial culture.     

In vitro maturation and germination of <Emphasis Type="Italic">Orychophragmus violaceus</Emphasis> microspores

Microspores cultured in vitro can be regarded as a system to study gene regulation, cell fate determination and cell differentiation during pollen development as well as an alternative method of genetic transformation in plants. In our study, pollen development and viability in Orychophragmus violaceus in vivo were determined and then pollen from the late unicellular stage was cultured in vitro. MS liquid medium + White vitamins + 2% (V/V) coconut milk + 0.5 M maltose, pH = 7.0 was the most appropriate for in vitro culture of Orychophragmus violaceus microspores. With this medium, the rates of in maturation and germination were 19.3% and 4.7%, respectively. Liquid medium with 0.6 M maltose + 1.6 mM boric acid + 2.9 mM Ca(NO₃)₂ + 29.6 μM vitamin B1, pH = 7.0 was optimal for germination of pollen matured in vivo. The rate of germination was 70.7%. Pollen matured in vitro cultured in similar medium exhibited a rate of germination of 62.7%. Hence, the experimental study showed that in vitro maturation of microspores is feasible and this experimental system can be applied to further theoretical and practical research.     

STUDIES ON POLLEN GERMINATION OF CERTAIN CUCURBITACEAE

Vasil , I. K. (Delhi U., Delhi, India.) Studies on pollen germination of certain Cucurbitaceae. Amer. Jour. Bot. 47(4) : 239—247. Illus. 1960.—Pollen grains of 8 members of the family Cucurbitaceae were cultured in artificial nutrient media. Among the sugars, sucrose proved to be the best for germination of pollen. Although growth regulators, vitamins, antibiotics and some other chemical substances also improved germination of pollen and length of pollen tubes, the effect of boric acid (0.005—0.02%) and borax (0.01%) was most outstanding. The role of sugars and boron in the germination of pollen is discussed.