Floral biology and artificial pollination in Dioscorea alata L.

Summary Floral biology of Dioscorea alata L. was studied. Anthesis occurred in male flowers by 12.30 h and in female flowers between 13.00 h and 14.30 h. Male flowers remained open for 4–5 hours and female flowers for 9–11 days.Natural pollination was practically absent but parthenocarpic fruit development was observed in rare cases. For hand pollination a simple and efficient pencil method was standardised. Pollen remained viable for 4–5 hours whereas stigma receptivity lasted for 9–10 days. The optimum time of pollination was found to be between 12.00 h and 15.00 h. Several factors like high relative humidity, atmospheric temperatures below 30°C and non-bagging the female flowers were found to promote fruit set.     

Different sex phenotypes of Cucumis sativus L. and C. melo L. and their endogenous gibberellin activity

Summary Gibberellins were extracted from seeds and green plants of different sex types of the closely related species Cucumis sativus L. (cucumber) and C. melo L. (muskmelon). Both seeds and green plants of monoecious and andromonoecious lines of C. sativus contained significantly higher gibberellin levels at all growth stages tested than did a gynoecious line. Gibberellin activity in the monoecious and andromonoecious C. sativus line reached a maximum at the growth stage corresponding to flower differentiation at cotyledonary and first leaf axils. Vernalization of seeds of gynoecious plants resulted in increased male tendency correlated with increased gibberellin activity. In contrast, monoecious and andromonoecious lines of C. melo were gibberellin deficient relative to hermaphroditic and gynoecious lines.Journal Article No 5534 from the Michigan Agricultural Experiment Station. This work was supported by a grant from the Herman Frasch Foundation.     

白蜡属植物的开花特性和动态观察

研究花器官形态结构和开花特性,为白蜡授粉受精提供理论依据。本研究选取了3个白蜡品种（‘鲁蜡2号’、‘鲁蜡5号’和‘金箭’）,对其开花特性、花器官构造进行观察。结果表明,白蜡品种雄株花期为11～13天,开花时间比雌株早13～15天;雌株‘鲁蜡2号’的花期为5～6天。3个白蜡品种的小花密集,开花后苞片2裂,花萼钟状4深裂,无花冠。雄花开花后露出舟形花药,花丝极短。雌花苞片开裂后露出雌蕊,柱头成熟时两裂,呈粉红色,花柱极短。扫描电镜下的3个白蜡品种苞片和花萼表面均有盾毛分布,不同品种间盾毛的形态有差异;‘金箭’、‘鲁蜡5号’的花药与花粉结构无显著差异;‘鲁蜡2号’整个雌蕊表面都有不规则褶皱分布。本研究可为进一步开展白蜡属植物的育种和种质资源创新利用研究提供参考。     

新疆核桃主栽品种开花及散粉特性研究

【目的】对新疆主栽核桃品种的开花物候期、花粉活力和散粉规律方面进行研究,旨在揭示开花及散粉规律,对提高授粉受精效果以及科学配置授粉树提供依据。【方法】以新疆‘新新2’、‘温185’ 两个主栽早实核桃品种为材料,在花期通过对花粉量统计测算,花粉活力测定、开花物候期观测、花期散粉量和日散粉量测定等研究。【结果】⑴两个品种每花蕾中花粉粒个数,‘温185’平均为7.70万粒,‘新新2’ 平均为7.14万粒。⑵两个主栽品种散粉量在空间方向基本一致,依次为：南部＞东部＞西部＞北部＞内部;同一方向散粉量,中部＞内部＞外部。⑶平均气温20―24℃是两个主栽品种最为适宜的核桃散粉温度。⑷‘新新2’与‘温185’ 雌雄花期可遇,同为约4d,但‘新新2’可进行自花授粉,而‘温185’因雌花失去可授性,不能进行自花授粉。【结论】温度在核桃散粉的过程中起着重要的作用;雄花在树冠不同空间方位存在散粉差异;自然条件下‘新新2’可进行自花授粉。     

Some observations on the floral biology of the carrot (Daucus carota L.)

The production of carrot seed sometimes presents the problem of the occurrence of seedless umbels. During an investigation into the cause of this phenomenon, a number of floral-biological data have been collected which are valuable both for the seed production and breeding of this crop.

1. 1.
   The distribution of male flowers and bisexual flowers. Both in the wild carrot and in 2 cultivated varieties the tendency to produce male flowers was encountered. In all forms tested the percentage of male flowers was practically negligible in the main umbel and was found to increase regularly in umbels of higher order. There were, however, clear differences in the mean percentage between the forms tested. Presumably the tendency to produce male flowers is determined genetically, but it may also be affected by the environment.     
   
   

灰色局势决策法在苦瓜强雌系育种中的应用

为了开展苦瓜强雌系育种多因素综合评估,有效选择苦瓜优异种质资源及筛选优良组合,应用灰色局势决策法,对配制的9个苦瓜强雌系杂交组合F1代的各主要性状进行综合评判。结果表明,9个组合的13个性状的权重系数大小顺序为：总产量＞单瓜重＞结果数＞横径＞单瓜长＞前期产量＞肉厚＞雌花率＞茎粗＞叶面积＞节间距＞第1朵雌花开放的天数＞主蔓第1朵雌花开放时节位。综合测度结果表明,43×K1综合效果测度值最高,为0.9343,定为优良组合重点配制。     

雄性不育野生茶树开花生物学特性

为观察野生茶树雄性不育株开花生物学特性,探讨野生茶树雄性不育表型特征。以野生茶树雄性不育株及可育株为试材,田间观察了野生茶树的开花物候期、单花发育进程和花器形态特征,并采用离体萌发法、染色法测定其花粉活力和柱头可授性。结果表明：野生茶树雄性不育株开花物候期为9月上旬—10月上旬,全花期持续约29~33天,花期与对照材料相近。雄性不育花从花芽分化至花瓣凋谢平均历时约107天,比对照长14天。雄性不育花器结构具有典型的雄不育特征,表现为花冠开展度小,花丝弯曲畸形,花药彼此粘连,皱缩干瘪,不裂药,花药内无花粉或有微量败育花粉。雄性不育花雌性器官发育正常,柱头从开花前1天至开花后4天具有可授性,最佳授粉时间为开花后1天。所调查的野生茶树雄性不育类型属于花药败育型和花粉败育型。     

Poor fruit setting in strawberries. I

In 1949 at least one of the Jucunda strawberry clones selected in the Netherlands was found to have a strong tendency to bad fruit setting, causing malformed fruits, nubbins, and resulting in entire or partial crop failure. This phenomenon was by no means new and has since been of more or less frequent occurrence.In the present paper a survey is given of the possible causes of a poor fruit set in strawberries in general; in a second article the investigations of the Jucunda variety will be dealt with.External causes of poor fruit setting are spring frost during the blooming period; damage caused to flowers by parasites, either insects, mites or fungi; unfavourable weather conditions during flowering; in growing under glass insufficient air circulation and insufficient pollination by bees due to keeping the frames closed too much; insufficient pollination in overcrowded beds; and unfavourable structure of the soil. However, these external factors can be eliminated to some extent by cultural measures.Therefore a more serious problem is presented by sterility or incomplete fruit setting, which is very complicated and determined genetically. Genetically, two types of strawberries can be distinguished: the all-female type, which is heterozygous for the sex factor, and the more or less hermaphrodite-male type, which is homozygous for that factor. In this latter group all kinds of intermediate forms are encountered between the all-male type with entirely sterile pistils and the almost entirely female type with only very few stamens.A good variety should have both well-developed stamens and entirely fertile pistils. Besides a fairly large number of varieties of which the stamens are well- or fairly well-developed and which have a high to moderate percentage of good pollen, there areA good variety should have both well-developed stamens and entirely fertile pistils. Besides a fairly large number of varieties of which the stamens are well- or fairly well-developed and which have a high to moderate percentage of good pollen, there are some varieties of which the stamens are usually much less developed and which produce only a low percentage of good pollen.Pistil-sterility is reflected on the one hand in all pistils of one or more of the later flowers of the inflorescence failing to set, owing to which the receptacle does not swell and berries are not developed. This phenomenon is regularly encountered in seedlings. On the other hand a certain number of the pistils of a flower may fail to set, resulting in malformed fruits.     

Emasculation of Tartary buckwheat (<Emphasis Type="Italic">Fagopyrum tataricum</Emphasis> Gaertn.) using hot water

Hot water treatment was applied to Tartary buckwheat (var. ‘Hokkai T8’) for emasculation. Apical clusters of flower buds were soaked in a constant temperature water bath (42–44°C) in the afternoon and then the flowers which opened in the next morning were used for the investigation of self-fertilization and the artificial pollination. Hand pollination was carried out by rubbing the anthers taken from the male parent (var. ‘Hokkai T10’) to the stigma of the flowers treated by hot water. The seed set by self-fertilization was almost 0% when treated at 42°C for 8 min or more, at 43°C for 5 min or more and at 44°C for 3 min or more. With artificial pollination, the best performance was obtained when treated at 44°C for 3 min, in which the seed set was 55.1% and the matured seed was obtained 37.7% of the hand-pollinated flowers. Nine out of 26 progeny seedlings emerged and the cotyledonal color of them were all reddish green, probably indicating the hybrid of ‘Hokkai T8’ and ‘Hokkai T10’. The hybridization was reconfirmed by the segregation in F₂. The hot water treatment at 44°C for 3 min was available to other seven varieties. From 24.5% to 100% of the hand-pollinated flowers set mature seeds though only one self-fertilized seed remained without artificial pollinations. This hot water treatment must be practically useful in hybridization breeding of Tartary buckwheat.     

华山松种子园花粉管理的技术研究

从1986年起,我们对平坝华山松幼龄林种子园进行开花习性,人工辅助混合授粉和施肥促进开花的研究。研究结果表明,幼龄林种子园具有一定的结实能力,开雌花株数达45.5%。但是雌球花败育率高(73%),有雄花株少(12%),着果率低(59%)。通过人工辅助混合授粉,可提高着果率16.7%,施肥可增加雄球花花数1倍以上。     

Induction of male flowering in gynoecious cucumbers (Cucumis sativus L.) by silver ions

Summary Silvernitrate (AgNO₃) and silverthiosulphate (Ag(S₂O₃)₂ ^3-) effectively induced male flowering in many nodes of 7 gynoecious cucumber genotypes in 3 glasshouse trials. A single spraying of the plants in the first true leaf stage with 3 mM Ag⁺ as Ag(S₂O₃)₂ ^3- or AgNO₃ (500 ppm) yielded many more staminate flowers than GA-3 (1500 ppm) and almost as many as 3 consecutive sprayings of GA-4/7 (50 ppm).Male flowering started about 3 weeks after treatment and lasted for a period of up to 4 weeks thereafter. Plants treated with silver ions did not elongate and grew normally; effective concentrations of AgNO₃ proved phytotoxic only in poor growing conditions, while Ag(S₂O₃)₂ ^3- never gave deleterious side-effects. Even very strongly female lines can be induced to male flowering with silver ions, thus increasing the feasibility of large scale seed production of gynoecious × gynoecious cucumber hybrids.     

Interspecific hybrids between kenaf (Hibiscus cannabinus) and roselle (H. sabdariffa)

The successful interspecific cross is reported for the first time between kenaf (Hibiscus cannabinus L.), a diploid species (2n=36) and roselle (Hibiscus sabdariffa L.), a tetraploid species (2n=72). Kenaf, grown for its bast fiber and also under investigation as a source of paper pulp, is fast-growing and well adapted to mechanical harvesting, but susceptible to root-knot nematodes. Roselle, also grown for its bast fiber, is slower growing, not well adapted to mechanical harvesting, but certain varieties are resistant to root-knot nematodes. Five hybrid plants were produced from the pollination of 4,445 flowers of kenaf with pollen from roselle; no hybrid plants were produced from 2,655 pollinations made in the reciprocal direction. One line of roselle was the parent of 3 of the 5 hybrids; one line of kenaf was the parent of 2 of these 3. The F₁ hybrids were triploid, and varied in vigor, growth habit and vegetative morphology, but had similar flowers. Two of the F₁ hybrids showed high pollen fertility, apparently as a result of restitution at first meiotic division leading to unreduced spores. These two hybrids each produced a small amount of seed, which gave rise to an F₂ population of 22 plants. The F₂ plants vary in vigor but are morphologically uniform, have thick leaves with mosaic sectors, and are presumably spontaneous allohexaploids. The theoretical possibilities of increasing the percentage of recovery of the F₁ interspecific hybrids and of developing a synthesized hybrid variety useful for bast fiber and paper pulp are discussed.     

四季蜜龙眼夏季开花坐果特性及传粉昆虫种类调查

为了解四季蜜龙眼夏季开花坐果特性和传粉昆虫种类,于夏季开花期间选定花穗记录雌雄花和果实数量,并以随机网捕方式采集传粉昆虫进行鉴定。结果表明:四季蜜龙眼夏季花期平均每穗开花天数为12.9天,雌雄花比例为1:6.57,授粉受精期的温度处于25～36℃之间,在较高的温度条件下雌花坐果率达到27.6%;雌花脱落占雌花数的11.1%,小果脱落占雌花数的61.3%。传粉昆虫有5目13科21种,以花金龟科的种类最多,占总数的33.3%;其次为蜂类和蝇类昆虫,分别占总数的30.1%和24.1%。     

Breeding Scorzonera hispanica L. by the polycross method

1. 1.
   Scorzonera is somewhat erratic in seed setting, but outdoor pollination is much better than pollination in glass structures. Selfing the plants by bagging some flowers of each plant together with flies did not give a lower seed setting than open pollination under the same conditions (see table 1). Vegetative propagation of Scorzonera-roots is relatively easy.     
   
   

矮壮素和赤霉素对黄芩生物量及根中黄酮类成分产量的影响

【研究目的】探讨外源矮壮素和赤霉素对黄芩生物量及根中黄酮类成分产量的影响,为中药材生产中外源激素的合理利用提供依据。【方法】对黄芩幼苗叶面分别喷施2ml 200mg/L矮壮素和赤霉素,第26天后,观察植株形态,测定植株高度、地下和地上部分生物量,并利用HPLC法和乙酰溴法分别测定地下部分黄酮类成分含量和地上部分木质素含量。【结果】(1)与对照组相比,矮壮素使植株叶片变绿变厚、花增多、花期延长、节间变短、茎粗大;赤霉素显著增加株高的同时,使叶片变小、绿色变浅、茎变细、腋芽生长明显。(2)矮壮素和赤霉素均使黄芩地上部分生物量增加,同时地下部分生物量降低。(3)矮壮素和赤霉素均使地下部分黄酮类成分的含量显著下降,同时显著提高地上部分木质素的含量。【结论】该实验表明,矮壮素和赤霉素使黄芩中碳源的分配集中于地上部分的生长和木质素的合成,不利于地下部分生物量和黄酮类成分的累积,因此不适于黄芩的中药材生产,并且可能也不适于以根或根茎为药用部位的其它中药材的生产。     

Gynoecious sex expression and stability in cucumber (Cucumis sativus L.)

Summary Results indicated that gynoecious stability in the F₁ is governed by partial dominance. The degree of gynoecious stability is dependent upon genotypes, stages of plant for AgNO₃ application and number of sprays. Depending upon the genotypes, the one-true-leaf stage and one spray of 250 ppm AgNO₃ showed more gynoecious stability in the F₁. Twice application of AgNO₃ at the two-true-leaf stage produced the maximum number of male flowers. Plants exposed to light for longer time (10.00 h) after AgNO₃ application produced less flowers than when exposed for shorter time (15.00 and 20.00 h).Present address: Division of Vegetable Crops, Indian Agricultural Research Institute, New Delhi-110012, India.     

化学药剂处理对蓖麻性别的影响

为明确不同浓度的化学药剂对蓖麻性别的影响,本试验以蓖麻两性系（E09004、E09009和E09002）和E09002单雌系为材料,分析了喷施不同浓度的GA3、NAA、乙烯利、6-BA和AgNO3对蓖麻雌雄花率的影响。结果表明：100 mg/L GA3有利于蓖麻雌花的形成,250 mg/L GA3则有利于雄花的分化,前者表现为雌花率上升,后者表现为雌花率降低;NAA和6-BA使雌花率增加,出现了纯雌株;乙烯利有利于雄花的分化,一定浓度的乙烯利可使两性株雄性化;AgNO3促雄效果明显,使两性株雄花率增加,单雌株出现少量雄花;同时试验还获得少数花性特殊（如全雄、纯雌）的材料。本研究为蓖麻的性别逆转诱导、单雌材料的繁殖及性别分化研究提供参考。     

The inheritance of winter hardiness in Pisum I

An F₃ hybrid population of the cross Early Perfection x Austrian Winter peas was fall planted at East Lansing, Michigan. The segregates that overwintered indicated that hardiness is inherited independently from other phenotypic characteristics. Thus, the possibility exists that the winter hardy character can be transferred from the Austrian Winter pea to commercial varieties. The development of a compact rosette of tillers is essential for winter survival and the hardy segregates must be able to form this rosette under fall growing conditions which normally force commercial types to flower and fruit. Differential survival of segregating populations under variable depths of snow demonstrated a strong protective influence of even shallow snow cover. Accordingly, air temperatures are less desirable than surface soil temperatures in determining cold endurance.     

5个美国山核桃优良品种开花等性状比较

为解决安徽地区美国山核桃品种少、产量低等问题,连续13年对引种的美国山核桃实生品种对比观察,筛选出‘安农1号’等5个优良适生品种。并对这5个品种的新枝及叶萌发生长节律、雌雄花开花物候、花期长短等特性进行观测分析。结果表明,5个品种新枝平均长度差异达到6.5 cm,叶平均长度差异3.3 cm;枝梢、叶、雄花序生长量最大均为温度最高日期;5个品种雄花盛花期持续时间相差不大;‘安农5号’雌花盛花期持续10天,比其他4个品种长3~5天;‘安农1号’、‘安农3号’、‘安农5号’均为同时型品种,‘安农2号’为雄先型品种,‘安农4号’为雌先型品种。