阴雨对‘大五星’枇杷柱头可授性和花粉活力的影响

以‘大五星’枇杷为试材,研究了阴雨天气对枇杷柱头可授性和花粉活力的影响。结果表明:阴雨天气的持续均可以使枇杷柱头可授性和花粉活力不同程度地降低,降低授粉效率,对枇杷生产均有负面影响。此外柱头可授性检测表明,‘大五星’枇杷柱头可授期为开花当天至花后第5天,在此期任何一天只要天气晴朗,柱头随即恢复并具有较强的可授性,此特性可以一定程度地减少阴雨天气带来的负面影响。     

The Effect of Summer Nitrogen Applications on The Quality of Apple Blossom

A summer application of nitrogen was used to induce the production of “ strong ” flowers for comparison with the " normal ” flowers produced on trees of Worcester Pearmain given only a spring application of nitrogen.

The flowers were given various pollination treatments to provide material for an assessment of flower quality. These included the following : auto and alio self-pollination and cross-pollination with diploid apple or pear at anthesis, cross-pollinations and self-pollinations at additional daily intervals subsequent to anthesis.

The stigmas of strong flowers remained receptive for a longer period than those of normal flowers.

After cross-pollination with a diploid apple, fertilization took place in 6-7 days. After self-pollination a typical incompatibility reaction was apparent. Pear pollen tubes showed an intermediate response.

Egg sacs in strong flowers continued to enlarge after those of corresponding normal flowers had ceased to grow. The fertilized ovules and embryo sacs of strong flowers showed a more rapid acceleration in growth rate than those of normal flowers.

Cell division in unfertilized ovules also continued for a longer period in strong flowers and appeared to be correlated with the behaviour of the egg sac.

Ovule longevity provided the most striking difference between the two flower types. The ovules of strong flowers remained capable of fertilization for almost twice as long as those of normal flowers.

Abnormalities of several types were seen in ovules. The most common was the production of secondary egg sacs, a feature of strong flowers which had been self-pollinated. Three types of secondary sac, micropylar, lateral and chalazal are described and illustrated.

The effects of rate of pollen tube growth, ovule longevity and the period of stigma receptivity in limiting the effective pollination period, are discussed. It is suggested that some variations in fruit set may be due to differences in flower quality. The use of summer or early autumn nitrogen is advocated as a method of improving blossom quality in certain varieties.     

小苍兰开花特性与繁育系统研究

综合运用杂交指数、花粉活力及柱头可授性、花粉/胚珠比、人工控制授粉试验等,对小苍兰的花部结构及繁育系统进行研究。结果表明：小苍兰雄蕊和雌蕊空间分离,花药紧贴花柱外侧,低于柱头约2 mm,在花朵开放的整个过程中雌、雄蕊的相对位置不变。小苍兰雌雄异熟现象明显,花药开裂时间与柱头可授期不同步,当花粉活力达到最高值时,柱头可授性还较低。小苍兰杂交指数（OCI）为 5,花粉/胚珠比（P/O）为1 614,人工授粉的坐果率高于自然传粉,由此判断其交配方式是以异交为主,自交为辅,繁育系统为兼性异交。     

肋柱花开花动态及繁育系统的研究

以肋柱花[Lomatogonium rotatum（L.）Fries ex Nym.]为材料,通过野外定点观察其花器官形态特征、开花动态和传粉昆虫,并采用花粉活力、柱头可授粉性、花粉/胚珠比（P/O）与杂交指数（OCI）估算及人工控制授粉等方法对其繁育系统进行测定。结果表明：（1）肋柱花单花花期6 ~ 7 d,单花开放分为花蕾期、初开期、盛开期、衰落期和凋落期,整个开放过程中柱头始终高于花药,开花后2 ~ 3 d花粉活力和柱头可授性均较强;（2）花粉/胚珠比（P/O）为551.02,杂交指数（OCI）为4,繁育系统以异交为主,部分自交亲和,需要传粉者,以蓟马为主要传粉媒介;去雄后套袋不授粉,果实结籽率为0,说明不存在无融合生殖。     

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.     

Effect of pistil age and pollen parent on pollen tube growth and fruit production of pistachio

Female pistachio (Pistacia vera) trees were hand pollinated with pollen from three different male genotypes 0,1,2,3 and 4 d after anthesis. Results were measured by mature fruit set and by fluorescence microscopy of pollen germination and tube growth in the pistil. Maximum pollen tube growth and fruit set of split nuts was achieved following pollination within two days of anthesis. Three day old pistils supported pollen tube growth, but fruit set was low. Four day old pistils supported little pollen tube growth or fruit set. Significant differences were also apparent between pollen parents, with low pollen tube growth and fruit set following interspecific pollination with P. atlantica pollen. All pollen tubes were observed to penetrate chalazogamously, and parthenocarpic production of blank fruits occurred in both unpollinated and pollinated treatments. The results indicate that for optimum fruit production of pistachio, pollen transfer must be achieved within 2 d of anthesis and pollination by P. atlantica should be avoided.     

莼菜传粉生物学及杂交技术研究

对莼菜花器官的结构、开花物候期、开花动态、柱头可授性、花粉活力、花粉/胚珠（P/O）、繁育系统、传粉方式及杂交技术进行初步研究。结果表明：莼菜群体花期为5月初～6月初,30 d左右,单朵花期2 d,同一朵花内的雌雄蕊在时间和空间上隔离。莼菜不存在无融合生殖现象,柱头可授期主要在开花第1天,人工授粉（第1天开放的花）结实心皮的比例为27.8 %,高于自然授粉（20.9 %）;花粉活力在自然条件下保持4～5 d。P/O平均为14 947,属专性异交（Obligate xenogamy）型。     

蜀葵开花与繁育特性研究

通过野外观察,对蜀葵自然居群的花部特征、开花过程、花粉/胚珠比、花粉生活力和柱头可授性及繁育特性等进行初步研究。结果表明:蜀葵群落花期约91 d,单花持续时间为(3.57±0.14)d。雄性先熟,雄性持续时间为(2.45±0.16)d,雌性持续时间为(1.55±0.16)d。花柱伸出时为直立状态,属柱头探出式雌雄异位,与花药间距离约3 mm。柱头伸出后约2~4 h后开始弯曲,直至与花药接触,此时的花粉生活力为42.33%,柱头可授性最强,存在潜在的延迟自交。授粉处理的结果表明,蜀葵不存在无融合生殖,自交亲和,以异交为主。其柱头裂片的反转运动有可能保证传粉者不足或缺乏时传粉的成功发生。     

Flower emasculation accelerates ovule degeneration and reduces fruit set in sweet cherry

Flower emasculation is commonly used to make flowers unattractive to pollinating insects and to carry out controlled pollinations. In sweet cherry, we have observed recurrent low fruit set after flower emasculation and compatible pollination without apparent causes. This led us to evaluate its effect on the progress of the reproductive phase and on fruit set in this species. Flower emasculation reduced by more than a half the fruit set obtained in crosses made during two consecutive years. This effect could be traced back to the first week after anthesis where weight increase of pistils from emasculated flowers was smaller and ovule degeneration was accelerated compared to pistils from non-emasculated flowers. Pollen tubes, which behaved similarly at the stigma-style level in emasculated and non-emasculated flowers, lost their directionality in the area close to the degenerated ovule in the ovary. While flower emasculation is valid to evaluate pollen tube performance in the style and to determine incompatibility relationships, the lower fruit set registered after emasculation alerts on its use in fruit set experiments and breeding programs.     

果梅花不同发育阶段花粉原位萌发及花粉管生长特性

为探明自花、异花花粉在果梅花的不同发育阶段原位萌发及生长的特性,以细叶青果梅为材料,取开花前6、4、2d、开花当天和花后2d的花(花蕾),分别于自花、异花授粉(莺宿)后12、24、48、72、96h切取花柱,用FAA固定液处理,荧光染色后压片观察。结果表明,自花花粉在柱头上的萌发率略低于异花(开花前4d存在显著差异),开花前6、4d极显著低于其他各阶段,花蕾越幼小花粉萌发越差,开花当天花粉萌发率超过80%;开花前4d之前的花柱内异花花粉管数量显著低于开花前2d及之后各期的,果梅开花前4d以前的花发育不充分;开花后2d生长到花柱基部的异花花粉管数量较多,属于有效授粉期。果梅在开花前4d开始具备抑制自花花粉管生长的能力,并且随着花的发育逐渐增强,开花当天最强,开花后开始减弱。果梅自交授粉期以开花前2～3d为宜。     

天山天池二倍体棱叶蒜的开花动态及交配系统

以分布于新疆天山天池的二倍体棱叶蒜(Allium caeruleum)为研究对象,观察记录了开花进程,测定其花粉活力和柱头可授性,并采用去雄、套袋、人工授粉等方法对其交配系统进行检测。结果表明:(1)伞形花序平均直径为(29.07±1.17)mm,花被片天蓝色,花期6—8月;两性花,平均小花数205.67±19.88个,密集,无株芽;小花开放历经弹头、张口、吐药、展开、抱合和萎蔫等过程,历时5~7 d;小花开放进程中花药和柱头间存在空间隔离,从第1枚花药伸出至6枚花药全部脱落以及柱头伸长至萎蔫各需要2~3 d;阴天比晴天分别延长散粉以及延迟柱头萎蔫0.5~1 d。棱叶蒜具有雄蕊先熟、雌雄异熟、雌雄异位以及吸引昆虫避免自交的花部特征。(2)花药开裂散粉4 h时花粉活力最强(79.23%±1.97%的花粉具有活力),36 h后降至很低,属于短寿命花粉。(3)联苯胺—过氧化氢和MTT法检测柱头可授性;花丝、花柱等长期部分柱头开始具有可授性,花丝、花柱合拢期至花丝萎蔫期柱头可授性最强。同一朵花雄蕊和雌蕊的可育期存在部分时间重叠,防止了杂交失败。(4)单花花粉量为31 275±3 651,胚珠数6,P/O值为5 212±608;杂交指数OCI为5;无自发的自花传粉现象,不存在风媒传粉和无融合生殖;倾向于异交为主、自交可育,具备兼性异交并需要传粉媒介的混合交配系统的特征。天山天池二倍体棱叶蒜还以种子休眠、鳞芽无性繁殖的生殖补偿方式保证特殊地理环境下的种群繁衍。     

菱传粉生物学研究

以6 个菱品种为试材，对花器形态特征、群体花期及单花开花动态、开花时间、柱头可授性、花粉活力、杂交指数 及传粉形式等进行观察测定。结果表明：菱花单生，两性，单花花期15 h，群体花期在5～10 月，盛花期在7～8 月；不同 品种在一天中的开花高峰期存在差异；柱头可授期主要在萼片开裂后2 h 内，结实率在50% 以上；花粉在自然授粉条件下活 力可保持7.5 h；以自花授粉为主，同时存在一定程度的无融合生殖和少量异花授粉。     

白及的花部特征与繁育系统

 通过野外观察、授粉特性分析、杂交指数估算及人工控制授粉试验等方法对白及野生居群的花部特征和繁育系统进行了研究。结果表明：在自然条件下,白及4-5月开花,群体花期约44 d,群体盛花期约12 d,集中在4月29日-5月10日,单株花期11 ~ 27 d,单花花期6 ~ 8 d。总状花序上具两性花3 ~ 11朵。在花朵开放的整个过程中,花药始终高于柱头且两者之间存在隔离。花粉成熟时由粘性物质聚结成团,无法散落至柱头。开花后3 d 内花粉活力和柱头可授性均较高。白及杂交指数为4。无论去雄与否,套袋后的花均不结实,说明其不能进行自然的自花授粉和无融合生殖。白及人工自花授粉、同株异花授粉和异株授粉的结实率分别为93.33%、90.00%和93.33%,自然条件下的结实率为5.26%。花粉成熟时由粘性物质聚结成团和缺乏有效的传粉媒介可能是白及自然条件下结实率低的主要原因。     

牛角瓜花部综合特征与繁育系统

野外调查发现,牛角瓜（Calotropis gigantean）的自然坐果率较低,影响了利用其种子纤维的开发前景。研究了牛角瓜的传粉生物学,观察了云南元江牛角瓜居群的开花进程、花部特征和访花昆虫,检测了其花粉活力与柱头可授性,并对其进行了人工授粉辅助试验。结果表明：（1）牛角瓜花为聚伞形花序,花冠蓝紫色,花期全年,单花花期7 ~ 8 d,在开花整个过程中花粉一直保持较强活力且柱头具有可授性,花药一直低于柱头,由蜡质薄膜包裹的花粉粒形成花粉块,无法散落至柱头,花药和柱头间存在空间隔离。（2）牛角瓜的杂交指数为4,说明其繁育系统以异交为主,部分自交亲和,需要传粉者。（3）人工授粉试验显示,牛角瓜不能在柱头表面完成授粉,而是在柱头腔中,且存在一定的传粉限制;没有自发的自花传粉现象,在自然条件下也没有无融合生殖现象,人工异株授粉结实率比自花授粉结实率高。（4）昆虫借助足部特殊结构将花粉块移出并将花粉块通过花药裂口插入柱头腔中以完成授粉;牛角瓜访花昆虫共有10余种,传粉昆虫主要有膜翅目的黑小蜜蜂、圆柄木蜂和木蜂。花粉限制是牛角瓜坐果率低的主要原因,可通过放养传粉昆虫来提高牛角瓜的坐果率,从而增加其种毛纤维的产量。     

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.     

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.     

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.     

Hand and Machine Pollination of Kiwifruit

ABSTRACT

Two artificial pollination field trials were carried out in Central Chile (32°S. Lat.) during the 1999-2000 season with ‘Hay-ward’ kiwifruit plants (Actinidia deliciosa (Chev.) Liang et Ferguson). The treatments for both trials used pollen collected from ‘Matua’ and included: flower to flower hand pollination; hand pollination using a velvet pad attached to a handle; and mechanical pollination using a portable pollen (1:1, pollen: licopodium) dusting machine; and a control treatment without artificial pollination. Trial 1 did not include bee hives as did Trial 2. In Trial 2, half of the selected shoots in each plant were isolated from bee pollination by means of a light fabric bag. A block design with 5 replications of one plant each was used in Trial 1, while in Trial 2 a fully random split plot (with and without isolation) with 5 replications was used. In both trials, flower to flower and pad pollination increased fruit set, fruit size, seeds and fertilized locules per fruit. Mechanical pollination also increased these variables but to a lesser degree. In the split plot design carried out in the Trial 2, even though there was an interaction between isolation and pollination treatment, the supplementary bee pollination tended to increase fruit size, seeds and fertilized locules per fruit.     

Flower morphology and number of aubergine (Solanum melongena L.) in relation to fruit load and auxin application

The effect of fruit load and auxin application on the flower morphology and flower number of two aubergine cultivars was investigated under greenhouse conditions. The flowers of plants that did not set fruit showed only minor fluctuations in flower and pistil mass, and in style and anther length. However, when plants were allowed to set fruit by pollination, flower and pistil mass, and style (but not anther) length were significantly reduced during the stage of fruit growth. Style length was also reduced in flowers formed after fruit had been set parthenocarpically by the application of auxin (IAA), but there was no significant effect of IAA on style length in the absence of fruit development. The number of flowers was reduced in the presence of IAA (with or without fruit set), or following fruit set by pollination. It is suggested that fruit load and development affect flower mass and style length of aubergine whereas auxin influences the number of flowers.     

艾比湖沙拐枣的花部特征与繁育系统

野外定点观察艾比湖沙拐枣（Calligonum ebi-nuricum）的花部特征和开花进程,运用杂交指数、花粉/胚珠比、花粉活力及柱头可授性、人工授粉试验等方法对其繁育系统进行测定。结果表明：在自然条件下,艾比湖沙拐枣5-7月开花,群体花期约70 d,单花花期4 ~ 6 d,单花开放进程分为5个阶段：花蕾期、初开期、盛开期、衰落期和凋谢期。艾比湖沙拐枣的花为两性花,在花朵开放的整个过程中花药始终高于柱头。雌雄异熟,雄蕊先熟,花粉在开花1 ~ 4 d具有较强的活力,柱头在开花2 ~ 5 d可授性较强。杂交指数等于5,花粉/胚珠比为2 464,结合人工授粉试验结果可以确定其繁育系统为异交为主,部分自交亲和,需要传粉者。访花昆虫主要有蜂类、蚁类、蝇类、甲虫类,其中蜂类数量最多,是有效的传粉者。