Gametophytic self-incompatibility causes seedlessness in ‘Kagzi Kalan’ lemon (Citrus limon)

The present study aimed to study the flower and pollen structure, pollen viability, in vitro pollen germination of ‘Kagzi Kalan’ lemon (Citrus limon (L.) Osbeck), and in vivo pollen tube growth in self- and cross pollination to understand the mechanism of seedlessness. The results revealed that Kagzi Kalan had tetra-colporate spherical shaped pollen of uniform size. The results of Acetocarmine and FDA test and in vitro germination indicated normal pollen viability and germinability in Kagzi Kalan. In vivo pollen tube growth showed > 50% pollen germination on stigma in all treatments though a greater number of pollen tubes at the mid style, base of the style, and near the ovule was found in cross pollination. Contrary to this, despite optimum pollen germination (53.51–70.37%) in self-pollination treatments, none of the pollen tubes reached the base of the style due to abnormal growth of pollen tubes, viz. curvatures, inhibition of pollen tube growth, and callose deposition. The inhibition of pollen tubes at the mid style under self-pollination treatments, and production of seeded fruits under cross pollination treatments, indicate the presence of self-incompatibility and the site of inhibition of pollen tubes. Thus, gametophytic self-incompatibility (SI) caused seedlessness in Kagzi Kalan by blocking fertilization in the ovary.     

Floral biology,pollination ecology and seed production of the ornamental plant Salvia splendens Sello

Summary

In this paper, the floral biology and pollination ecology of Salvia splendens are described. All flower characteristics (red corolla, large tubular flowers with abundant but dilute nectar) indicate that S. splendens is adapted to hummingbird pollination. Honeybees, however, were also found to be good pollinators of this plant. Apis mellifera was equally effective in pollinating S. splendens as hand pollination and open pollination, resulting in a 300% increase in seed set compared with bagged control plants. The much smaller stingless bee Tetragonisca angustula was not an effective pollinator of these flowers since during visitation its body failed to touch the stigma. Although pollination seemed not to be the only limiting factor in seed production, external pollinators enhance seed production in S. splendens, and Apis mellifera is an effective, commercially available pollination agent of this economically important ornamental plant.     

Determination and confirmation of S-RNase genotypes of apple pollinators and cultivars

Summary

We analysed the S-RNase genotypes of 23 crab apple (Malus spp.) pollinators and 102 cultivars of domestic apple (Malus pumila Mill.) by PCR amplification and digestion. Within the 23 pollinators, four pollinators, ‘Hopa’, ‘Jack’, ‘Pink Perfection’ and ‘Profusion B’, each had two unidentified S-RNase alleles. These cultivars should be useful pollinators for all domestic cultivars. Twenty-one of the domestic cultivars exhibited S-genotypes contrary to those expected from their supposed parentage, suggesting that one or both reported parents were wrong. We confirmed many of the S-RNase genotypes by pollination tests.     

Sexual compatibility within and between olive cultivars

Summary

Self- and cross-incompatibility of the olive cultivars Frantoio, Manzanillo, Kalamata, Pendolino, and Picual were investigated using a 5 × 5 diallel matrix. Pistils were collected seven days after controlled pollinations on the day of flower opening, and pollen tubes were detected by fluorescence microscopy. Diallel analysis showed significant specific combining ability, general combining ability and reciprocal effects between cultivars for pollen tube growth in the pistil. ‘Frantoio’ was cross-compatible, as either a male or female parent, with each of the other cultivars, but showed a high degree of self-incompatibility. ‘Manzanillo’, ‘Kalamata’, ‘Pendolino’, and ‘Picual’ were crossincompatible, and all except for ‘Manzanillo’, were self-incompatible. It is concluded that ‘Frantoio’ is a good general polleniser for the other cultivars investigated. Pollen tube growth decreased in discrete steps from stigma to upper style, and from upper style to lower style, with the result that only one, and rarely more, pollen tube penetrated ovules. The sex ratio of flowers, and pollen viability using fluroescein diacetate staining and in vitro germination, were examined. ‘Frantoio’, ‘Manzanillo’ and ‘Pendolino’ had more than 80% perfect flowers, while ‘Kalamata’ and ‘Picual’ had less than 30%. ‘Frantoio’ had the highest pollen viability, ‘Kalamata’ and ‘Picual’ were intermediate, and ‘Manzanillo’ and ‘Pendolino’ the lowest. Pollen staining and both in vitro and in vivo germination provided the same male fertility rankings of cultivars.     

Fruit set after self-pollination at different floral stages and its relation to pollen-tube growth and stylar S-RNase content in Japanese apricot (Prunus mume Sieb. et Zucc.)

Summary

To investigate fruit set after self-pollination at different floral stages, and its relationship to the S-RNase content of the style in Japanese apricot, which exhibits gametophytic self-incompatibility (GSI), the cultivar ‘Xiyeqing’ was selfand cross-pollinated at –6, –4, –2, 0 and +2 d after anthesis (DAA). At –6 and –4 DAA, the percentage fruit set was low, suggesting that the propensity to seed set was weak during this period. At –2 DAA, the percentage fruit set, after self-pollination, reached a maximum of 5.97%. Thus, the effective time of self-pollination to obtain inbred seed was –2 DAA. Soluble protein extracts of styles at each floral stage were subjected to iso-electric focussing. The results showed that S-RNase began to be synthesized from –6 DAA, reached its maximum expression 2 – 3 d before anthesis, and was degraded slowly after anthesis. The number of pollen-tubes arriving at the stylar base, as detected by fluorescence microscopy, varied at –2, 0, and +2 DAA. The number of pollen-tubes arriving at the stylar base, and the percentage fruit set after self-pollination, exhibited a positive correlation (r = 0.8615; P = 0.1), while the S-RNase content per style showed a negative relationship to fruit set percentage (r = –0.9640; P = 0.01), and to the number of pollen tubes arriving at the stylar base (r = –0.9380; P = 0.01) during this period. This implied that the S-RNase content in the style was mainly responsible for the low percentage fruit set and the low number of pollen-tubes arriving at the stylar base after self-pollination.     

Improving pollination of almond (Amygdalus communis L., Rosaceae) using electrostatic techniques

Summary

Supplementary pollination of almond using electrostatic techniques was tested in a three year study (1996–1998) in Northern Israel. We used an electrostatic pollination device and tested its effects on fruitlet set, fruit set, yield weight and nut weight. We also tested its ability to pollinate flowers on the tree from the distal to the proximal part of the branches. We found that when individual branches were pollinated, fruitlet set was in accordance with the expected deposition rate of pollen grains on the stigma: electrostatic 1 open pollination > non-electrostatic + open pollination + open pollination > electrostatic pollination > non-electrostatic pollination > spontaneous self pollination. Fruit set results showed the same pattern but were not as precise. Electrostatic pollination of individual trees resulted in an insignificant increase in pollen germinability on the stigma. The highest germinability was on the distal part of the branch and the lowest was on the proximal part of the branch, in all pollination treatments. Electrostatic pollination increased yield as compared with non-electrostatic and open pollination. Nut weight, however, decreased slightly with increased yield. We suggest that electrostatic pollination can be an important method for pollen supplementation in almond orchards when honeybee pollination is insuf®cient and when the trees can withstand the added portion of nuts, resulting from improved pollination.     

Physiological Breakdown in Stored Monarch Plums

Summary

Several pollination studies carried out on different, self-incompatible almond cultivars and seedlings have shown the presence of variable levels of fruit set following self-pollination that could be attributed to partial self-incompatibility (PSI). PSI is an intermediate reproductive behaviour, described in some angiosperm species, which indicates that self-incompatibility is a quantitative and plastic trait. The present study was performed to substantiate the occurrence of PSI in almond by studying ten cultivars that are traditionally considered to be self-incompatible (four of which had previously shown fruit set after self-pollination). These cultivars were analysed by microscopic observations of the progression of pollen tubes through the pistil following controlled self-pollination, determinations of fruit set after bagging flower buds, and molecular identification of the parentage of the fruits obtained using consensus PCR-primers for Prunus S-RNase alleles. The results showed that, in nearly all cases, the pollen tubes did not enter the ovary and, from a total of 5,349 bagged flower buds, only 17 fruits were obtained. In all cases, PCR analysis of the plants obtained after germination of these seeds showed a band corresponding to an S-RNase allele not present in the maternal progenitor, clearly indicating that they could only have arisen from cross-pollination.Therefore, the low fruit set values observed in some of the cultivars studied were not due to a breakdown in the self-incompatibility response that confers PSI, but to very low rates of contamination with foreign pollen. These results corroborate the self-incompatibility phenotype of the cultivars studied here, and highlight the importance of ascertaining the identity of the parentage in any progeny obtained after bagging.     

Cross-compatibility of apple cultivars possessing S-RNase alleles of similar sequence

Summary

We investigated the functional differences in three pairs of S-RNase alleles having similar sequences. It was confirmed using pollination tests that S₁₉ and S₂₈ behaved as different alleles, while S₁₇ and S₁₉ appeared to be the same allele. Our previous new allele designation of S_6b in place of S₁₇ and S₁₉, and not S₁₉ and S₂₈, from S-RNase sequence analyses was therefore confirmed. The deduced amino acid sequences of S₃ and S₁₀, although showing high similarity (94%), were functionally distinct.     

Incompatibility in apricot (Prunus armeniaca L.): Methodological considerations

Summary

The recent introduction of new self-incompatible varieties of apricot has required further research on the extent of self-incompatibility in apricot and its genetic determinism. The different laboratory and field techniques utilized to date for incompatibility studies in apricot have often given markedly diverging results, leading to difficulty of interpretation. The purpose of this study was therefore to make a critical assessment of the reliability of the various methods, to obtain a more precise tool for compatibility studies. Forty-eight apricot crosses were assessed over a two-year period and the results compared using the normal field techniques (active pollination without bagging, active pollination with bagging and passive pollination) and laboratory tests (fluorescence test). The present study reports on some aspects of the different techniques and offers methodological suggestions for improved practical application of the various tests.     

Effects of genotype and stigma development stage on seed set following intra- and inter-specific hybridization of Dianthus spp.

The caryophyllaceae is a family of flowering plants commonly known as the pink or carnation family. Members of this family are widely grown as ornamental plants. The species Dianthus chinensis, Dianthus barbatus, and Dianthus superbus include notable examples of such ornamental varieties. Intra- and inter-specific hybridization is important for the breeding of improved varieties and, therefore, it is desirable to optimize the efficiency of cross-pollination procedures within this family. Here, we conducted intra-specific pollination using four lines of D. chinensis, and inter-specific pollination between D. chinensis, D. barbatus and D. superbus genotypes. For each of these crosses we recorded information of pollen viability, stigma development stage at time of pollination, pollen germination on the stigma surface and pollen tube elongation within the stigma, and final seed set. Pollen viability levels were determined at the start of anther dehiscence, which occurred on day 1 of flower opening. The genotypes D. chinensis var. ‘Bz2’, D. barbatus var. ‘Xb’, and D. superbus wild species ‘Qm’ all displayed good levels of pollen viability (i.e. between 68% and 75%); D. chinensis vars. ‘H58III’, ‘H68I’ and ‘H6II’ showed lower levels of pollen viability (i.e. between 32% and 51%). In each Dianthus line, the stigma organs were observed to undergo morphological changes during the 1–7 d following flower opening. We have characterized these changes as five distinct development stages, namely, ‘column’ (day 1), ‘Y-like’ (day 2), ‘Y-shaped with slight curve’ (days 3–4), ‘Y-shaped horn-like’ (days 5–6), and ‘wilting’ (day 7). Pollen was artificially applied to stigma organs at each of these development stages and aniline blue staining was used to follow pollen tube germination on the stigma surface and pollen tube elongation down the length of the stigma. This showed that the ‘Y-shaped slightly curved’ stigma stage (3–4 d) was optimal for pollination. The ‘Y-shaped horn-like’ stage (5–6 d) was also receptive to pollination. By contrast, the earlier ‘Y-shaped’ (2 d) and ‘column’ (1 d) stages, and also the later ‘wilting’ (7 d) stage, were far less receptive. Parallel field experiments were conducted in which seed set was measured following the artificial pollination of flowers at different development stages. These data also indicated that the optimal time for pollination was during 3–4 d of flower opening. This conclusion held true for both intra- and inter-specific crosses of the various Dianthus lines. Thus, stigma receptivity in Dianthus does not become optimal until 3–4 d after flower opening. Since anther dehiscence occurs at 1 d (i.e. when stigma are at the unreceptive ‘column’ stage), this suggests that Dianthus employs a delayed self-fertilization strategy. We also found a significant effect of genotype on pollen tube growth and seed-set values. The highest numbers of seed per flower were achieved when the D. superbus wild species ‘Qm’ was the female parent in inter-specific crosses. Thus, genotype and stigma development are identified as key factors that determine the success of cross-pollination in Dianthus lines.     

Habitat edge effects decrease litter accumulation and increase litter decomposition in coastal salt marshes

Context

Habitat fragmentation is known to be one of the leading causes of species extinctions, however few studies have explored how habitat fragmentation impacts ecosystem functioning and carbon cycling, especially in wetland ecosystems.

Objectives

We aimed to determine how habitat fragmentation, defined by habitat area and distance from habitat edge, impacts the above-ground carbon cycling and nutrient stoichiometry of a foundation species in a coastal salt marsh.

Methods

We conducted our research in a salt marsh in the Mid-Atlantic United States, where the foundation grass species Spartina patens is being replaced by a more flood-tolerant grass, leading to highly fragmented habitat patches. We quantified decomposition rates, live biomass, and litter accumulation of S. patens at patch edges and interiors. Additionally, we measured relevant characteristics (e.g., habitat area, elevation, microclimate) of S. patens patches.

Results

Habitat edge effects, and not habitat area effects, had distinct impacts on ecosystem functioning. Habitat edges had less litter accumulation, faster decomposition rates, a warmer and drier microclimate, and lower elevations than patch interiors. Patches with low elevation edges had the fastest decomposition rates, while interiors of patches at any elevation had the slowest decomposition rates. Notably, these impacts were not driven by changes in primary production.

Conclusion

Habitat fragmentation impacts the above-ground carbon cycling of S. patens in coastal wetlands by altering litter decomposition, but not primary production, through habitat edge effects. Future research should investigate whether this pattern scales across broader landscapes and if it is observable in other wetland ecosystems.

     

Photoperiod-sensitive male-sterile mutant in tomato and its potential use in hybrid seed production

Summary

The current practice of manual emasculation of tomato ¯owers for hybrid seed production is labour-intensive and contributes signi®cantly to the high cost of seed. Here we report on a photoperiod-sensitive, single gene male-sterile mutant (7B-1) in tomato which is 100% male sterile in long days (LD, minimum of 12.h daylength) in summer ®eld conditions, but produces many male-fertile ¯owers in short days (SD, 8.h). In LD, 7B-1 ¯owers contain stamens that are pale, short and in the anthers microspore mother cells are differentiated but meiosis does not occur, i.e. microspores and pollen grains are not formed. Unlike the wild type ¯owers, the style and stigma of 7B-1 ¯owers are well exposed and this allows for ready access for pollination without emasculation. In SD, mutant ¯owers possess normal-looking orange-yellow anthers that enclose the stigma and produce normal viable pollen, which when used for pollination of 7B-1 ¯owers yield good fruit- and seed-set. The 7B-1 seed in turn generate a 100% population of male-sterile plants all of which can be used as female parents for hybrid seed production. The female fertility is not affected in 7B-1 ¯owers in both LD and SD conditions. The 7B-1 mutant has been grown in various ®eld locations including, Saskatoon, California, Florida and in Chile, and at all locations it has shown stable male sterility. The 7B-1 mutant is a simple, natural and costeffective system that has a strong potential for use in commercial-scale production of tomato hybrid seed.     

Evidence for a major role of honeybees (Apis mellifera) rather than wind during avocado (Persea americana Mill.) pollination

Summary

The purpose of this study was to determine the relative importance of honeybee (Apis mellifera) activity and wind in the pollination of avocado (Persea americana Mill.) trees. Data on the pollination rates of five cultivars of avocado, honeybee densities, ambient temperatures, and wind velocities were recorded in an orchard in Israel on 61 d over a period of 7 years. The effect of wind velocity on avocado-flower pollen under laboratory conditions was also studied. Rates of pollination showed highly positive correlations with honeybee density, whereas no correlations were observed with wind velocity. Under laboratory conditions, no effect of wind velocities equivalent to those measured in the field was observed on avocado-flower pollen. Our results agree with earlier work in which wind contributed only slightly to avocado yield. Hence, we conclude that contrasting data which show the effectiveness of wind pollination in avocado are not relevant to most avocado-growing regions, including Israel and California. It is, therefore, strongly recommended that avocado growers continue using honeybees for pollination.     

Studies on the Nutrition of Tulips and Narcissi

Summary

We explored the effects of pollination method (hand cross-, hand self-, automatic self-, and open-pollination) and pollen source on fruit set and growth in four red-skinned pitaya (Hylocereus spp.) cultivars [‘Vietnam White’ (‘VNWhite’), ‘Chaozhou 5’, ‘Orejona’, and ‘F11’] in Taiwan.‘VN-White’ has white flesh, while the other three cultivars have red flesh. There were no significant differences in pollen viability or germination rate among the four cultivars, irrespective of whether the pollen was collected at night (approx. 20.30 h) or on the following morning (approx. 08.30 h).The results also indicated that ‘VN White’ was fully self-compatible and exhibited a high fruit set percentage (80 - 96%) following all pollination treatments. This cultivar produced the largest fruit from both hand self- and openpollination, compared to the three other cultivars tested. ‘Chaozhou 5’ was partly self-compatible, and ‘Orejona’ and ‘F11’ were completely self-incompatible. Hand cross-pollination significantly increased the fruit set percentages and mean fruit fresh weights (FWs) in ‘Chaozhou 5’ and ‘Orejona’. Pollen source also significantly affected the fruit set percentage and fruit FW. ‘VN-White’ (after self-pollination) and ‘Chaozou 5’ (after crossing with ‘VN-White’) gave superior fruit set percentages and fruit FWs. Reciprocal crosses between ‘Orejona’ and ‘F11’ also resulted in high fruit set percentages as well as large fruit in both cultivars. Therefore, the source of pollen and the method of pollination can affect fruit production in some cultivars of pitaya. Self-compatibility in ‘VN-White’ concurs with the morphology of its flowers in which the anthers lie in close proximity to the stigma.The distance between the anthers and the stigma may be used an indicator of whether hand pollination is necessary for a pitaya cultivar.     

Cross- and self-compatibility in various species of the genus Rosa

Summary

Self- and cross-compatibility was evaluated under field conditions in 48 taxa belonging to all sections of subgenus Rosa and subgenus Platyrhodon in the genus Rosa. Four species exhibited fruit set through self-pollination out of the 28 diploid species tested. In contrast, nine out of 12 tetraploid species, all of pentaploid species, and four out of five hexaploid species exhibited fruit set through self-pollination. Thus, it may be generally said that the self-incompatibility in the genus Rosa breaks down with polyploidization. The relationship between self-incompatibility and ploidy level is discussed.     

The use of a New Technique in Breeding for Solidity in Radish

Summary

Field and laboratory experiments were conducted to study if rain could wash-off pollen grains from the surface of the stigma and consequently affect the efficiency of fertilisation in loquat (Eriobotrya japonica Lindl.). Flowers of the loquat cultivar, ‘Dawuxing’, growing in the field, were emasculated, pollinated by hand with pollen of the cultivar ‘Longquan No.5’, then sprayed with water to simulate the effect of rain at –8, –4, –2 h before, –0 h (immediately before hand-pollination) , +0 h (immediately after hand-pollination), and 2, 4, 8, or 12 h after pollination. A control to which no water treatment was applied was also included in the assay. Meanwhile, additional assays were performed in the laboratory to improve the resolution of the field study by using earlier treatments. Here, treatments were performed by pollinating, immersing, and shaking a branch with flowers in a container of water in the laboratory –120, –60, –30, –0, +0, 30, 60, or 120 min before or after hand-pollination. One additional sample was immersed, shaken, then hand-pollinated, and immersed and shaken (ISPIS) again. The results showed that the numbers of pollen grains that germinated, and the percentages of fruit set, differed significantly between the –4, –2, –0, or +0 h treatments and the non-water-treated control in the field assays, especially in the case of the –0 h and +0 h treatments in which the stigmas were washed immediately before or after hand-pollination. However, the –8, 2, 4, 8, and 12 h treatments did not show significant differences from the non-treated control. On the other hand, the laboratory experiments showed that all washing treatments reduced the number of germinated pollen grains retained on the stigma, and the immersion treatments at –30, –0, +0, or 30 min as well as the additional ISPIS treatment, showed significant differences from the non-treated controls in the numbers of pollen grains retained on the stigmas. In conclusion, the results showed that adhesion of pollen grains to the stigmas in loquat was rapid and strong, and that the simulated rain treatment was not able to wash-off pollen grains completely from the stigma surface, except in the –0 h and +0 h treatments.     

甘蓝自交不亲和系、自交系花粉、柱头蛋白质的等电聚焦电泳和游离氨基酸分析

结球甘兰(Brassica oleracea L. var. capitata)自交不亲和系的测定,通常是用田间自交法来进行,这种方法费工费时。自建立了用水溶性苯胺蓝显示花柱中花粉管的技术后,又逐渐发展了利用荧光染色法快速测定自交不亲和性的方法。此法根据柱头上花粉萌发的数量确定不亲和程度,尚欠精确。研究表明,孢子体自交不亲和系统的花粉与柱头的识别机制是由S等位基因编码的S蛋白质决定的。美、英、日等国已先后分离鉴定出了这类S蛋白质。本试验旨在通过对甘蓝自交不亲和系及自交系花粉、柱头的蛋白质和氨基酸组分的分析,探讨利用蛋白质特性来快速测定植物孢子体型自交不亲和性的可能性。 材料与方法 试材采用西南农大园艺系蔬菜育种教研室选育的甘蓝自交不亲和系‘二乌叶86057’、‘北黑大86035’,二系统均是多代自交、高度稳定的自交不亲和系,1983年以来田间自交亲和指数均接近于0;自交系‘虹桥86047’,该材料也为多代自交,但亲和性稳定,1986年田间自交亲和指数达13.06。 等电聚焦电泳和氨基酸分析均测试“花粉”(P)、“柱头”(S)和“受粉后柱头”( P S)三项。花粉:取自开花前套袋隔离的花枝;枝头:隔离袋内,开花前1-2天彻底去雄,     

Rain effect on pollen–stigma adhesion and fertilization in almond

The fact that rainy weather negatively affects production in almond is well-known by growers. However, as far as we know, no previous study has been carried out in this species to determine if the rain is able to wash off pollen grains from the stigma surface and consequently affect fertilization efficiency. To answer this question, flowers of the self-compatible almond cultivar ‘Antoñeta’ were emasculated on branches of trees in the field, pollinated by hand with pollen of the cultivar ‘Marcona’, and sprayed with water to simulate the rain effect at 4, 8, 24 and 48 h after pollination. A control for which no treatment was applied was also included in the assay. Seven days after spraying the flowers, the number of germinated pollen grains on the stigma was recorded in 10 pistils for each treatment by fluorescent microscopic observation. In addition, for each treatment the initial and final fruit set were determined at 30 and 60 days after pollination, respectively. The following year additional assays were performed in the field and in the laboratory in order to complete the study with earlier treatment times. Thus, an assay of rain simulation in the field at 0 and 2 h, and other consisting on immersing a branch with flowers and shaking it in a water container in the laboratory at 0, 30, 60 and 120 min after pollination were performed. One sample more was immersed, shaken, then pollinated and again immersed and shaken. The results from field assays showed that adhesion of pollen grains to the stigma was very quick and strong, and the treatments did not significantly affect pollen–stigma adhesion and subsequent fruit set. On the other hand, laboratory results showed that all washing treatments decreased the number of germinated pollen grains on the stigma, mainly when the flowers were immersed before pollination. In conclusion, the results showed that the simulated rain was not able to completely wash off pollen grains from the stigma surface, although it seems to affect adhesion in forthcoming pollinations.     

自交不亲和甘蓝亲和花粉授粉早期差异蛋白质分析

 为从蛋白质的角度揭示自交不亲和甘蓝亲和授粉早期花粉与柱头相互作用,将蛋白质组学方法应用于自交不亲和性甘蓝柱头与亲和花粉互作早期差异蛋白质的研究。结果表明,亲和授粉后3 ~ 5 min与1 h对比,有116个差异蛋白质点,而授粉后1 h与2 h差异不显著。按照特异表达与变化量大的蛋白质点优先原则,初步选取差异点中71个点做质谱分析,鉴定出31个可信差异蛋白质。与亲和授粉后3 ~ 5 min组相比,1 h组中特异表达蛋白质有19个,上调表达9个,下调表达3个。31种蛋白质的生物信息学分析表明,有两种蛋白与前人发现的与花粉管在柱头中生长发育相关蛋白相同,其他29种参与包括胁迫与防御应答在内多种生理过程。对早期差异蛋白中这种“既有促进花粉管发育的蛋白,也有与防御相关蛋白”现象分析表明,花粉管生长性侵入柱头的过程有可能伴随着柱头抗性的提高。     

Biochemical changes involved in self-incompatibility in two cultivars of olive (Olea europaea L.) during flower development

Biochemical analyses were carried out to characterise the basis of self-incompatibility in the olive (Olea europaea L.) cultivars ‘Amygdalolia’ and ‘Konservalia’. Multiple interactions between cells of different types, origin, and function occur in the pistil. Endogenous factors play important roles in ovary and fruit development before (Stage 1) and during pollination (Stage 2), and after fertilisation (Stage 3). Changes in carbohydrate, protein, H₂O_2, and calcium ion concentrations, and in peroxidase, catalase, superoxide dismutase, and ascorbate peroxidase activities in pistil tissue before and during pollination, and after fertilisation were investigated. In both cultivars, H₂O₂ concentrations were significantly higher in pistil tissue before pollination, after which they started to decrease in Stage 2 and continued non-significantly in Stage 3. Peroxidase, catalase, superoxide dismutase, and ascorbate peroxidase activities were lower at Stage 1 and Stage 2, whereas these enzyme activities increased at Stage 3 in both cultivars. The lowest concentration of calcium ions was observed at Stage 1, whereas at Stage 2, calcium ion concentrations increased and reached their highest level, then decreased at Stage 3. Calcium ion concentrations in ‘Konservalia’ were higher than in ‘Amygdalolia’. In ‘Konservalia’, the highest protein concentration was observed at Stage 2. No significant differences were found in carbohydrate concentrations between the two cultivars. The biological significance of the presence of these products may differ between Stage 1, when they have a defence function, Stage 2 when there are interactions between pollen and pistil, and Stage 3 after fertilisation. This study provides support for the hypothesis that there is a correlation between self-incompatibility, stress-related enzyme activities, and calcium ion concentrations in the pistils of olive.