Histochemical localization of enzymes in the stigma and style of Gossypium hirsutum L. during pre- and post-pollination stages.

The distributional pattern of some enzymes (esterase, beta-D-galactosidase, succinate dehydrogenase and malate dehydrogenase) is described in the dry stigma and closed style of Gossypium Hirsutum L. during pre- and post-pollination stages. All the four enzymes indicated granular reaction and increased activity in the transmitting tissue and its surrounding cells during post pollinated stage. The possible physiological role of these enzymes in pollen tube growth in vivo in stigma and style is discussed.     

Structure of a sugar chain of a protease inhibitor isolated from barbados pride (Caesalpinia pulcherrima Sw.) seeds

An asparagine-linked sugar chain of a protease inhibitor from barbados pride (Caesalpinia pulcherrima Sw.) was liberated by hydrazinolysis. After N-acetylation, the reducing end residue of this carbohydrate unit was coupled with 2-aminopyridine and the pyridylamino (PA-) derivative was purified by gel-filtration and reversed-phase HPLC. The structure of the resulting PA-sugar chain was determined mainly by stepwise exoglycosidase digestions and 500 MHz 1H-NMR spectroscopy and proved to be as follows: (formula; see text).     

Calcium snapshots in the stigma and style of medlar (Lycium barbarum L.) during pollen germination and pollen tube growth suggest active calcium oscilations

Abstract

The stigma (tip of the pistil) of medlar is wet and covered with stigmatic exudate at anthesis. The exudate contains many vesicles with abundant calcium precipitates. After deposition on the stigma, the pollen grain undergoes hydration, displaying signs of calcium ion (Ca²⁺) transfer from the exudate vesicles into the pollen grains. Calcium precipitates in the pollen cytoplasm are concentrated into small vacuoles that fuse to form large vacuoles, which provide turgor pressure to push the cytoplasm to the apical region of the growing pollen tube. Many calcium precipitates are present in the stylar transmitting tract, which displays a calcium gradient: fewer precipitates are localised in the distal (upper) transmitting tissue below the stigma, and more precipitates are present in the transmitting tract at the style base. The emporal and spatial distribution of calcium in the stigma and style of medlar suggests that it satisfies the demand for calcium in vivo and played some functional significance.     

Evaluation of pollen tube growth ability in Petunia species having different style lengths

Pollen tube growth is essential for the fertilization process in angiosperms. When pollen grains arrive on the stigma, they germinate, and the pollen tubes elongate through the styles of the pistils to deliver sperm cells into the ovules to produce the seeds. The relationship between the growth rate and style length remains unclear. In previous studies, we developed a liquid pollen germination medium for observing pollen tube growth. In this study, using this medium, we examined the pollen tube growth ability in Petunia axillaris subsp. axillaris, P. axillaris subsp. parodii, P. integrifolia, and P. occidentalis, which have different style lengths. Petunia occidentalis had the longest pollen tubes after 6 h of culture but had a relatively shorter style. Conversely, the pollination experiments revealed that P. axillaris subsp. parodii, which had the longest style, produced the longest pollen tubes in vivo. The results revealed no clear relationship between the style lengths and the growth rate of pollen tubes in vitro. Interspecific pollinations indicated that the styles affected pollen tube growth. We concluded that, in vitro, the pollen tubes grow without being affected by the styles, whereas, in vivo, the styles significantly affected pollen tube growth. Furthermore, interspecific pollination experiments implied that the pollen tube growth tended to be suppressed in the styles of self-incompatibility species. Finally, we discussed the pollen tube growth ability in relation to style lengths.     

Observation of Flowering Process of Grape (<i>Vitis vinifera</i> L.)—Insight into the Starting of Pollination of Flower Hiding in Calyptras (Cap)

It is generally agreed that many Vitis vinifera L. cultivars are self-fertile, where self-pollination often occurs before capfall in a process called cleistogamy. Therefore, it is difficult to identify the right time to remove stamens before self-pollination during the cross-breeding of grape. For this paper, we observed the process of grape flowering and measured the pollen viability and stigma receptivity of grape flowers of ‘Shine Muscat’ in order to identify the starting time of self-pollination before capfall and to provide useful information for improving the efficiency of cross-breeding. The results demonstrate that the anther is not cracked during the visible clusters and separated clusters stages. Meanwhile, in the separated floral buds, flowering begins, and full bloom stages, the pollen viability is 60.7%, 73.2% and 80.3%, respectively; however, at the berry set stage, pollen viability drops to zero. The top of the mature stigma is composed of a layer of nearly cylindrical papillary cells, and the stigma receptivity for pollen changes with the development of flowers: in particular, no reaction was observed in the visible clusters stage; weak positive reaction at the separated clusters stage; strong positive reaction at the separated floral buds, flowering begins, and full bloom stages; and no reaction at the berry set stage. In the separated floral buds stage, pollen tubes were seen germinating in the style. In the flowering begins stage, more pollen tubes were observed at the entry of the ovary. During the full bloom stage, most pollen tubes elongated into the ovary base and some entered the pearl hole. At the berry set stage, newborn endosperm nucleus could be seen in the ovule. From the above, we can conclude that the initiation time of closed fertilization for ‘Shine Muscat’ grape can be judged as the separated floral buds stage, and it is best to discard the stamen before the separated floral buds stage when conducting cross-breeding.     

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。     

Response of in vitro pollen germination and pollen tube growth of groundnut (Arachis hypogaea L.) genotypes to temperature

Air temperatures of greater than 35 °C are frequently encountered in groundnut‐growing regions, especially in the semi‐arid tropics. Such extreme temperatures are likely to increase in frequency under future predicted climates. High air temperatures result in failure of peg and pod set due to lower pollen viability. The response of pollen germination and pollen tube growth to temperature was quantified in order to identify differences in pollen tolerance to temperature among 21 groundnut genotypes. Plants were grown from sowing to harvest in a poly‐tunnel under an optimum temperature of 28/22 °C (day/night). Pollen was collected at anther dehiscence and was exposed to temperatures from 10° to 47·5 °C at 2·5 °C intervals. The results showed that a modified bilinear model most accurately described the response to temperature of percentage pollen germination and maximum pollen tube length. Genotypes were found to range from most tolerant to most susceptible based on both pollen characters and membrane thermostability. Mean cardinal temperatures (T_min, T_opt and T_max) averaged over 21 genotypes were 14·1, 30·1 and 43·0 °C for percentage pollen germination and 14·6, 34·4 and 43·4 °C for maximum pollen tube length. The genotypes 55‐437, ICG 1236, TMV 2 and ICGS 11 can be grouped as tolerant to high temperature and genotypes Kadiri 3, ICGV 92116 and ICGV 92118 as susceptible genotypes, based on the cardinal temperatures. The principal component analysis identified maximum percentage pollen germination and pollen tube length of the genotypes, and T_max for the two processes as the most important pollen parameters in describing a genotypic tolerance to high temperature. The T_min and T_opt for pollen germination and tube growth, rate of pollen tube growth were less predictive in discriminating genotypes for high temperature tolerance. Genotypic differences in heat tolerance‐based on pollen response were poorly related (R² = 0·334, P = 0·006) to relative injury as determined by membrane thermostability.     

The vitality of the Serbian spruce (Picea omorika) pollen during the long-term cryopreservation

Abstract

This article studies differences in the vitality (germination rate and pollen tube length) of fresh pollen and pollen stored at ?20 °C for 14 years of Serbian spruce (Picea omorika [Pan?i?] Purkyne). Fresh pollen was sampled from 24 trees from a Serbian spruce seed stand area on the site of Bela zemlja (43° 48′ 32″ N, 19° 44′ 25″ E) in the area of Mount Zlatibor (Serbia) in two successive years. Six nutrition media with different sucrose concentrations (0%, 5%, 10%, 15%, 20% and 25% aqueous solution) were used to assess the vitality of the pollen. Variance analysis shows significant differences among years of pollen sampling, years of cryopreservation, trees, and sucrose treatments for pollen germination for both germination rate and pollen tube length. The results indicate that climate conditions preceding the pollen maturation period had an impact on the pollen quality as well as on the pollen vitality during the years of cryopreservation. Inter-individual variability (differences between trees genetic variability) was very pronounced and enabled selection of pollinator trees that retained their initial vitality during the period of cryopreservation. This periodicity in Serbian spruce full flowering might have significant practical application in the breeding of this important species.     

凯特杏花粉的离体培养及影响因子分析

采用离体培养法,在不同培养基组分含量、pH值、温度及植物生长调节物质的培养条件下,对凯特杏(Prunus armeniacaL.cv Katy)花粉的离体萌发和花粉管生长状况进行观察研究。结果表明:(1)凯特杏花粉离体萌发及花粉管生长的适宜培养基为20%蔗糖 0.04%硼酸 0.01?Cl2,最适pH为6.0,最适温度为20℃,培养20 h后,花粉的萌发率达68.76%,花粉管长度达1 083.53μm。(2)不同植物生长调节物质对花粉萌发和花粉管生长作用不同,赤霉素浓度为5~8 mg/L、矮壮素浓度为10~150 mg/L、多效唑浓度为5~10 mg/L时对凯特杏花粉萌发和花粉管生长都有促进作用,但国光丁酰肼对凯特杏花粉萌发和花粉管生长均有抑制作用。     

Organization of the Stigma and Transmitting Tissue of Rice,Oryza sativa (L.)1

Abstract: The stigma of Oryza sativa (L.) is typically dry and plumose. The pistil is bifurcated just above the ovary. The distal parts of the two main branches are densely covered by multicellular, multiseriate papillae. The papillae are covered by a cuticle‐pellicle layer. The pecto‐cellulosic wall of the papillae is distinctly three‐layered. The transmitting tracts of the two main axes are not clearly demarcated, and are made up of several compactly arranged cell layers around the vascular bundle. The cells of the transmitting tissue are polygonal, narrow and elongated. They show plasmodesmata on the transverse, as well as longitudinal walls. The extracellular matrix in the transmitting tissue, containing polysaccharides and pectic substances, is restricted to the corners of the cells, forming long, narrow, linear canals along the axes.     

Environmental Effects on Components of Pollen Performance in Faramea occidentalis (L.) A. Rich. (Rubiaceae)1

Studies focusing on gametophytic competition have focused on differences in pollen performance (e.g., pollen germination rate and pollen tube growth rate) among donors in order to examine genetic sources of variation in siring success among them. Donors that produce the fastest growing pollen tubes are expected to fertilize more ovules relative to donors with slow growing pollen tubes under conditions of gametophytic competition. However, the performance of pollen in the field is known to be influenced by environmental conditions in addition to the genotype of donor plants. This field study of Faramea occidentalis was conducted to: (1) determine the effect of environmental conditions during pollination on pollen performance; (2) measure differences among pollen donors in pollen performance; (3) determine if the pollen of different donors responds differently to a variety of environmental conditions surrounding pollinated flowers; and (4) measure differences among pollen recipients in pollen performance. Single-donor crosses were made between four pollen donors and four pollen recipients under a variety of environmental conditions. Pollen performance was then quantified as the growth rate of the fastest pollen tube, the mean pollen tube growth rate, and by a pollen germination index. Pollination environment (the environment surrounding a pollinated flower) and recipient significantly affected all three measures of pollen performance. Pollen donors did not differ overall in pollen performance. However, there was significant among-donor variation in two of the five pollination environment conditions. Future studies of variation in relative siring success may benefit by considering pollination environment in addition to donor and recipient identity.     

植物生长调节物质对丰水梨花粉萌发和花粉管生长的影响

采用花粉液体培养法研究了植物生长调节物质对梨花粉萌发和花粉管生长的影响,结果表明：较低浓度的赤霉素、三十烷醇、吲哚乙酸及2,4-D均能促进花粉萌发和花粉管生长,而超过一定浓度时却起抑制作用,最适宜于花粉萌发和花粉管生长的赤霉素浓度为50～300mg／L,三十烷醇为3～100mg／L,吲哚乙酸为5～25mg／L,2,4-D为5～10mg／L。萘乙酸对花粉萌发和花粉管生长有抑制作用,抑制程度随培养基内其浓度的增大而加强。多效唑和脱落酸对花粉萌发有抑制作用,其抑制程度随浓度的上升而增强,但他们对花粉管生长却有促进怍用,其最适宜于花粉管生长的浓度分别为400mg／L和60mg／L,超过此浓度后,促进作用又有所下降,甚至出现抑制作用,如多效唑浓度达到1000mg／L时,能强烈地抑制花粉管生长。     

淫羊藿花粉萌发及花粉管生长研究

运用方差分析、多重比较和正交实验方法对淫羊藿花粉的萌发和花粉管生长进行了研究.结果表明:培养基内硼酸、硝酸钙、蔗糖在一定浓度范围内,对花粉萌发及花粉管生长起促进作用,但超过一定浓度时则起抑制作用;镁和钾对花粉萌发及花粉管生长影响不显著.在正交实验中蔗糖和H3BO3对淫羊藿花粉萌发有显著影响,而培养基组分间没有明显的交互作用.淫羊藿最适花粉液体培养基为15%蔗糖 40 mg/L H3BO3 40 mg/LCa(NO3)2·4H2O;在pH值为5.0、25℃和600 lx光照时淫羊藿花粉萌发和花粉管生长最好.     

培养基组分及pH值对梨花粉萌发和花粉管生长的影响

采用花粉液体培养法研究不同培养基组分和pH值对梨花粉萌发和花粉管生长影响.结果表明:培养基内硼酸、氯化钙、PEG-4000、蔗糖、葡萄糖、麦芽糖、山梨醇、果糖在一定浓度范围内,对花粉萌发及花粉管生长起促进作用,但超过一定浓度时起抑制作用;最适的培养基组分为:30mmol/LMES、0.01%硼酸、0.03%CaCl2·2H2O、15%PEG-4000、5%果糖 或5%山梨醇、10%蔗糖 ,最适的pH值为6.5.在该培养基内梨花粉萌发率约为59.2%,花粉管生长长度为966.3μm.     

桔梗花粉萌发与花粉管生长研究

以2年生桔梗植株为材料,采用液体培养法研究了培养基种类、PEG、蔗糖、pH以及培养温度、培养时间对桔梗花粉离体萌发生长的影响,结果表明:(1)浓度为100~150 g.L-1的PEG可显著促进桔梗花粉萌发和花粉管的生长;200~250 g.L-1PEG显著促进花粉萌发,但对花粉管生长的作用不显著。(2)100 g.L-1的蔗糖有利于花粉萌发和花粉管生长,高浓度蔗糖(200 g.L-1)有明显抑制作用;(3)桔梗花粉离体萌发和花粉管生长的适宜培养基为ME3+BK+10%蔗糖+150 g.L-1PEG(pH5.8);(4)25~40℃条件下桔梗花粉均可较好萌发,以30℃培养1.5 h为最佳培养条件。     

Temperatures during flower bud development affect pollen germination,self‐incompatibility reaction and early fruit development of clementine (Citrus clementina Hort. ex Tan.)

• One of the key environmental factors affecting plant reproductive systems is temperature. Characterising such effects is especially relevant for some commercially important genera such as Citrus. In this genus, failure of fertilisation results in parthenocarpic fruit development and seedlessness, which is a much‐prized character. Here, we characterise the effects of temperature on flower and ovary development, and on pollen–pistil interactions in ‘Comune’ clementine (Citrus clementina Hort. ex Tan.).
• We examine flower bud development, in vitro pollen germination and pollen–pistil interaction at different temperatures (15, 20, 25 or 30 °C). These temperatures span the range from ‘cold’ to ‘hot’ weather during the flowering season in many citrus‐growing regions.
• Temperature had a strong effect on flower and ovary development, pollen germination, and pollen tube growth kinetics. In particular, parthenocarpic fruit development (indicated by juice vesicle growth) was initiated early if flowers were exposed to warmer temperatures during anthesis.
• Exposure to different temperatures during flower bud development also alters expression of the self‐incompatibility reaction. This affects the point in the pistil at which pollen tube growth is arrested and confirms the role of sub‐ and supra‐optimal temperatures in determining the numbers of pollen tubes reaching the ovary.

     

Pollen viability,germination capability and pollen production level of some grape varieties (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

In this study, pollens of Burdur dimriti, Sariemin, Tilki kuyrugu, Razaki, Buzgulu, Siyah buzgulu, and Siyah gemre table grape varieties (Vitis vinifera L.) grown in Isparta, Turkey were tested in vitro for viability, germination capability, and production level. It was determined that active pollen levels varied between 23.8 % and 80.8 % in FDA (flourescein diacetat), 31.5 % and 68.8 % in TTC (2,3,5-triphenyl tetrazolium chloride) tests. In respect to pollen germination rates, the best medium in hanging drop method and saturated petri method were 20 % sucrose concentration and 1 % agar+15 % sucrose solution, respectively. The highest and the lowest pollen production levels per flower were determined 9000 in Siyah gemre and 2906 in Siyah dimrit grape varieties, respectively.     

梅花个体内花柱长度的变异及其对繁殖成功的影响

植物个体内花型的变异影响繁殖成功, 雌性繁殖性状的变异可能影响雌性的繁殖成功, 也可能作为花粉的受体影响雄性的繁殖成功。然而, 植物个体内不同花柱长度的花产生的花粉是否影响植物的繁殖成功却少有研究。梅(Armeniaca mume)是原产我国的重要木本花卉和经济果树, 我们的野外观察发现在同一植株内, 不同花的花柱长度有变异, 存在长柱型、短柱型和雄花型(雌蕊败育)三种花型, 是比较雌性繁殖性状的变异对两性繁殖成功的影响的理想材料。本文主要测量了不同花型的花部特征, 统计花期, 并开展体外花粉萌发以及人工控制授粉实验。结果表明: 长柱型的花冠直径、雌蕊长、单花花粉数、花粉体积显著大于短柱型和雄花型。长柱型的单花期以及雌花期显著长于短柱型。长柱型、短柱型以及雄花型花粉在活体柱头上的萌发率没有显著性差异, 雄花型的花粉管长度显著高于长柱型和短柱型。长柱型为母本的花粉萌发率以及花粉管的长度要显著高于短柱型。长柱型、短柱型、雄花型花粉授粉与自然对照处理的坐果率没有显著性差异, 而长柱型为母本的坐果率要显著高于短柱型为母本的坐果率。这些结果表明野生梅花的长柱型为母本有利于花粉的萌发和花粉管的伸长, 有高的坐果率; 但其作为花粉供体的雄性功能与其他花型没有差异。