中国北亚热带油橄榄(城固32)开花生物学特性研究

为研究北亚热带内陆地区油橄榄（Olea europaea L.）开花物候、开花样式及花器官特征,探讨其有性繁殖系统的特点。试验对西秦岭南坡地区油橄榄（城固32）的开花生物学进行研究,统计开花进程,雄花和两性花在花序上的着生位置和数量,测定雄花和两性花形态指标并切片观察,电镜扫描分析雄花与两性花花粉粒。结果表明：（1）在北亚热带北缘内陆气候条件下油橄榄花期集中在5月,单株花期15~20 d,盛花期持续4~6 d;（2）油橄榄具有雄全同株的性系统且花器官较小,雄花及两性花都具有正常发育的雄蕊。通过制作石蜡切片观察,发现两性花的雌蕊正常发育,而雄花只有较小的子房和败育的柱头;（3）雌蕊是两种花型花器官生物量差异的主要部位,两性花雌蕊的生物量明显比雄花大（P<0.01）,树体分化出雄花投入的资源更少;（4）雄花与两性花在花粉量、花粉粒大小上差异不显著,在着生位置上,花序轴顶花全部为两性花,雄花出现在花序轴的中部和基部的几率分别是21.13%和30.77%。油橄榄品种城固32具有典型的雄全同株现象,雄花更倾向于在花序上出现的位置在行使它雄性功能方面并无优势可言,而且雄花花粉粒在数量、活力方面也没有优势,但是雄花的出现增加了花粉数量和P/O值,提高了植株的雄性适合度,雄花的出现也降低了两性花落花导致的树体资源浪费,保障其在资源有限的环境中能够繁殖最大化。     

Synchronization of Cell Division During Flower Initiation in Third-Order Buds of Silene

Plants of Silene coeli-rosa were induced to flower with sevenlong days and then returned to non-inductive short days. Third-orderbuds were formed more than three weeks after the beginning ofinduction and third-order flowers were initiated about one weeklater. Comparison of the mitotic index with the ratio of cellsin the G2 and G1 phases of the cell cycle for each third-orderapex provided evidence for synchronization of cell divisionjust before flower initiation. It is suggested that this resultsfrom changes of competence of the apical cells to react to theirinternal environment rather than because of the arrival of afloral stimulus at the shoot apex. Silene, cell division synchrony, flowering, evocation, mitotic index, cell cycle, competence     

Apical Growth and Modification of the Development of Primordia During Re-flowering of Reverted Plants of Impatiens balsamina L

Impatiens balsamina L. was induced to flower by exposure to5 short days and then made to revert to vegetative growth byreturn to long days. After 9 long days reverted plants wereinduced to re-flower by returning them to short days. Petalinitiation began immediately and seven primordia already presentdeveloped into petals instead of into predominantly leaf-likeorgans. However, the arrangement of primordia at the shoot apex,their rate of initiation and size at initiation remained unchangedfrom the reverted apex, as did apical growth rate and the lengthof stem frusta at initiation. The more rapid flowering of thereverted plants than of plants when first induced, and the lackof change in apical growth pattern, imply that the revertedapices remain partially evoked, and that the apical growth patternand phyllotaxis typical of the flower, and already present inthe reverted plants, facilitate the transition to flower formation. Impatiens balsamina, flower reversion, partial evocation, shoot meristem, determination, leaf development     

The Interaction of Genetic, Environmental, and Hormonal Factors in Stem Elongation and Floral Development of Cucumber Plants

Hypocotyl length was found to vary between cucumber plants carryingdifferent genes controlling sex expression. Among lines havingonly unisexual flowers (genotype M/M), the homozygous monoeciousplants (st⁺/st⁺) had significantly longer hypocotyls than theirgynoecious counterparts (st/st), heterozygous gynoecious plants(st+/st) being intermediate. Similarly, hypocotyls of plantsof an andromonoecious line (st⁺/st⁺ m/m) were significantlylonger than in their hermaphrodite counterparts (st/st m/m).Differences in intemode length were also significant and inthe same direction. Since stem and particularly hypocotyl elongationin cucumber is known to be very sensitive to applied gibberellin,these findings suggest the existence of differences in the effectivelevels of endogenous gibberellins in the different sex types,higher levels being correlated with stronger male tendency.This conclusion is in good agreement with the known effect ofapplied gibberellin on sex expression (enhancement of the maletendency) in cucumber. Application of gibberellin (GA₄+GA₇) and exposure to ‘summer’conditions (long days and relatively high temperature) inhibitedthe development of pistillate flowers while ‘winter’conditions (short days, lower temperature) had a similar effecton staminate flowers. The effect was in either case specific,that is, limited to flower development. It is concluded thatexogenous and endogenous gibberellins affect not only the initiation,but also the further development, of flowers in the cucumber.     

Evidence for a Flowering Inhibitor Produced in Long Days in Kalanchoe blossfeldiana

Experiments with Kalanchoe blossfeldiana are described in whichperiods of short-day treatment were interrupted by intercalatedlong days or light breaks during long dark periods. The effectsof 24-hour dark periods preceding and following such intercalatedlong days were also investigated. The results of these experiments have shown that: Single longdays intercalated between numbers of short days have a positiveinhibitory effect on flower initiation and are not merely ineffective.The inhibitory effect expressed as the number of inductive cyclesannulled is approximately additive, provided the long days areinterspersed with short days, but not if several long days aregiven consecutively. On the average 1 long day is capable ofannulling the flower-promoting effect of about 1 short days.To a first approximation flower numbers in Kalanchoe increaseexponentially with the number of inductive cycles given—upto at least 12 short days; the inhibitory effect of long daysinterspersed with short days also fits an exponential curve;i.e. the inhibition is roughly proportional to the amount ofprevious photo-periodic induction. A light break of as littleas 30 seconds' duration given in the middle of a long dark periodis as inhibitory as a long day. If followed by a long dark periodthe inhibition of an intercalated long day is almost completelyneutralized; a long dark period preceding it has no such effect. These results have been interpreted as due to the interactionof a flowering inhibitor with a reaction leading to flowering.A mechanism involving competitive inhibition of an adaptivelyformed enzyme has been described as a possible example of thekind of reaction which could account for the results presented.     

Distribution of Cashew Flower Sex-types between Clones and Sides of Tree Canopies in Tanzania

Production of male, hermaphrodite and abnormal flowers was studiedon the north, east, south and west sides of the cashew treecanopy from Jul. to Dec. 1992 at the Agricultural Research InstituteNaliendele, Southern Tanzania. Flowers were recorded daily onselected clones throughout the main flowering season and subsequentlyyield of each clone was also recorded. Results showed differencesin the number of flower types both between clones and betweensides; however, there were consistently more male than othertypes of flower. Significant yield differences between cloneswere not detected and so could not be used to provide unambiguousevidence of the relationship between yield and flower characteristicsbut did indicate that clonal differences were present in termsof earliness of yield production. Anacardium occidentale L.; cashew; flowering; sex-types; clones; Tanzania; sides of canopy; yield     

Interaction of vernalization, photoperiod and high temperature in flowering of Arabidopsis thaliana (L.) HEYNH.

Flowering of Arabidopsis thaliana (L.) HEYNH., var. "Stockholm",plants, raised from vernalized seeds, may be modified by thephotoperiodic conditions or a short (1 week) exposure to hightemperature (32°C) following vernalization, depending onthe duration of the cold treatment. When vernalization is partial(1 to 4 weeks at 4°C), both short days (8hr light) and hightemperature have a devernalizing effect, but when the cold requirementhas been fully satisfied, after 5 to 6 weeks at 4°C, devernalizationis no longer possible. There is no interaction between photoperiodand high temperature. Fully vernalized plant flower in bothlong and short days, although flowering is delayed in shortdays. This delay is not a photoperiodic effect, however, butmay be ascribed to the decreased radiant energy available inan 8-hr photoperiod. Thus, fully vernalized Arabidopsis plantsare day-neutral. (Received November 5, 1969; )     

A gradual reduction of female structures in the pistillate flowers ofRicinus communis L. (castor-bean) with chlorflurenol (morphactin)

Chlorflurenol (morphactin) EMD 7301 W (60, 120 and 240 mg I^?1) when applied at five to seven leaf and 10–12 leaf stage induced hermaphrodite flowers in the inflorescences ofRicinus communis. The hermaphrodite flowers were mostly apical in position unlike the apical female flower in the control. With an increase in the time gap between sowing and emergence of the inflorescence there was a reduction of the female structures in the hermaphrodite flowers. The last formed inflorescences had an apical male flower in place of a female. The largest number of inflorescences with an apical male or hermaphrodite flower were produced with 60 mg 1^?1 applied at five to seven leaf stage. The hermaphrodite flowers failed to set fruits.     

Seed Germination in Amaranthus retroflexus L. as Affected by the Photoperiod and Age During Flower Induction of the Parent Plants

Seed germination in Amaranthtis retroflexus, a facultative shortday plant, was affected by the parental photoperiodic conditions.Seeds from parents grown continuously in short days (SD, 8 h)had a higher dark germination and a greater response (at 30°C) to a short irradiation or low temperature pretreatmentthan seeds from plants grown continuously in long days (LD,16 h). Daily night breaks of 1 h in the middle of the long-nightinhibited the SD induction of flowering as well as the SD promotionof germinability. Germinability of seeds produced by plantsinduced to flower in LD by 1, 2, or 3 SD was lower than thatof seeds produced by plants grown continuously in SD, and decreasedwith the age of the parent plants at the time of flower induction.     

Flowering of Stylosanthes guianensis in Relation to Juvenility and the Long-Short Day Requirement

Seedlings of Stylosanthes guianensis var. guianensis were grownin long (14 h) days in five temperature regimes for varyingperiods before transfer to short (11 h) days at 30 ?C/21 ?C.The juvenile phase before seedlings responded to inductive conditionswas c. 45–50 d, 50–60 d and 60–70 d for cv.Schofield, cv. Cook and C.P.I. 34906 respectively, which ispositively related to their critical photoperiod for flowering.Temperatures favourable for growth (e.g. 30 ?C/26 ?C) reducedthe juvenile phase in C.P.I. 34906 and in Cook, which did notflower in 11 h days unless previously exposed to more than 18long days. In a second experiment cv. Cook was confirmed as a long-shortday plant. Seedlings were grown for 50 d in a glasshouse withnatural daylength extended to 13, 14, 16 or 24 h before transferto 12 h photoperiods. Cook floral development was positivelyrelated to daylength provenance before transfer and plants incontinuous 12 h did not flower. Shortening daylength after 48 cycles of 12 h to 11.75 h didnot result in continued floral development in Cook plants butcv. Graham plants were initiated or transitional by 75 d. Key words: Stylosanthes guianensis, Photoperiod, Temperature, Flowering     

Effect of Number of Photoperiodic Cycles on Flowering and Fruiting in Early and Late Varieties of Okra (Abelmoschus esculentus (L.) Moench.)

Early and late varieties of the short day plant, Abelmoschusesculentus (L.) Moench. (= Hibiscus esculentus L.), were subjectedto various numbers of short days (SD; 10 h natural daylight)before transfer to 16 h long days. Short day treatments werestarted at the time of cotyledon release following seed germination,and their effects on the induction and development of flowersand fruits were recorded. While early okra required 6 SD cyclesfor the induction of flowering in all plants, late okra required14. However, both varieties needed more than 20 SD cycles forflower opening; flower buds produced by plants given fewer SDcycles abscinded with little or no development. In both varieties,the number of flower buds produced on each plant increased asthe number of short day cycles was increased from 5 to 20; flowerbuds were initiated at more axillary bud sites on the main stem.Three fruits were formed on each plant of both varieties subjectedto more than 30 SD cycles but, while the last formed fruit abscindedwithout development, the other two developed and became filledwith seeds. However, the greatest yield in fruit dry weightwas from plants kept under SD throughout and also in late okraplants given 55 SD. In general, the total number of seeds perplant increased as a larger number of SD cycles were imposed.     

Intra‐specific pollen polymorphism in Mimosa pigra (Mimosaceae)

Five different types of pollen tetrads were detected from the short and long stamens of the male and hermaphrodite flowers of the androdioecious species, Mimosa pigra L. Light (LM) and scanning electron microscopes (SEM) were used in this study to redescribe the pollen forms and to identify the various pollen types encountered. An identification key and relative percentages of these pollen types were also presented. The study showed that the long stamens of the male flowers and those of the hermaphrodite ones have five (I, II, III, IV and V) and two (I and V) pollen types respectively, whereas the short stamens of both male and hermaphrodite flowers have only one pollen type (type I). We report here the first incidence of intra‐specific pollen polymorphism in androdioecious species.     

Studies in the Physiology of the Onion Plant: IV. THE INFLUENCE OF DAY-LENGTH AND TEMPERATURE ON THE FLOWERING OF THE ONION PLANT

At temperatures above about 17° C. inflorescence initiationin growing onion plants, as in stored sets, is suppressed whetherthe plants are kept in long or short days. Independently ofcurrent day-length and of previous day-length treatment, ifthe plants are sufficiently large initiation begins very shortlyafter the temperature falls below c. 15° C. Emerged infiorescencesappear some ten or so weeks later. Small plants are unable toinitiate inflores cences under any of the conditions tested,and actual size (perhaps leaf area) rather than leaf or nodenumber seems to be the important factor. Inflorescence emergenceis suppressed at high temperatures in short days or long days;in long days bulb formation also suppresses emergence at lowertemperatures. In long days at temperatures sufficiently lowfor bulbing to be delayed, however, emergence is accelerated.Plants which have produced bulbs in long days in the summershow a delay of inflorescence emergence in the following winter.     

Increased Pentose Phosphate Pathway Activity Linked to Floral Induction in Apices of Spinacia oleracea during Short Days

A quantitative cytochemical study of glucose-6-phosphate dehydrogenaseactivity as a marker of the pentose phosphate pathway (PPP)was made on shoot apices of Spinacia oleracea kept either continuouslyin short days for up to eight weeks or transferred for a singleperiod of 20 h to continuous light after between three and eightweeks in short days. By the time the apices kept in continuousshort days showed morphological changes relating to the floralstate, the PPP activity was already elevated. From four weeksonwards, the apices were more readily induced to the floralstate as evidenced by the increased PPP activity. In addition,the level of PPP activity achieved in the short-day apices asthey progressed to the floral state was as great as that observedin the apices induced to flower by a 20-h day. Spinacea oleracea, pentose phosphate pathway, shoot apex, cytochemistry, glucose-6-phosphate dehydrogenase, floral induction     

Factors Affecting the Flowering of Andropogon gayanus Kunth. Responses to Photoperiod, Temperature and Growth Regulators

Andropogon gayanus is a short-day plant with a critical daylengthfor flowering between 12 and 14 h. Flowering is more intenseas the daylength is shortened from 12 h to 8 h, initiation isalso accelerated by increasing durations of short-day treatment.Plants flower more readily with increasing age. The maximumflowering response can be induced by short-day exposure of onlyone expanding leaf. A fixed number of short days distributedamong different groups of leaves on the plant gave less floweringthan the same number given to only one group. Approximately25°C was optimal for flowering. Root removal treatmentsin short day reduced both growth and flowering responses. Application of the growth regulators indol 3yl-acetic acid,abscisic acid, gibberellic acid or dimethylaminosuccinamic acid(B9) was inhibitory to flowering in all cases but gibberellicacid and B9 applied simultaneously had no inhibitory effect.Growth hormone treatments failed to stimulate flower developmentin long day. These results are discussed in relation to the internal mechanismscontrolling growth and flowering.     

Mutant dn Influences Dry Matter Distribution, Assimilate Partitioning and Flowering in Lathyrus odoratus L.

The flowering mutant dn in sweet pea was used as a tool to study¹⁴C-assimilate and dry matter partitioning with respect to nutrientdiversion theories on the control of flower initiation. Wildtype plants (Dn^h) are photoperiodic and exhibit late floweringand profuse basal branching in short days while mutant plants(dn) are day neutral, early flowering and devoid of basal laterals.In short days, dn plants exported a significantly greater proportionof assimilate acropetally than (Dn^h) plants and the upper portionof dn plants had a greater dry weight. These differences werereduced dramatically when basal laterals were excised regularlyfrom the (Dn^h) plants although the difference in flowering remained.However, the effect of dn on resource allocation within theapical region may be more important in regard to flowering thanthe effect on acropetal versus basipetal movement. In shortdays, the dn plants partitioned significantly more resourcesinto their internodes and petioles, and less into their leaflets,than Dn^h plants as shown by dry weight and ¹⁴C-assimilate measurements.These differences were apparent from as early as node 7 up tothe node of flower initiation in dn plants (node 30) and theywere not eliminated by removal of basal laterals from Dn^h plants.Differences between dn and Dn^h plants in partitioning and floweringwere largely eliminated under long days. The fact that in thisspecies a single gene influences both resource allocation andflower initiation lends further support to nutrient diversionhypotheses on the control of flowering. Key words: Assimilate partitioning, branching, flowering, mutant, sweet pea     

Inhibition of growth and synchronised cell division in the shoot apex in relation to flowering in Silene

When plants of Silene coeli-rosa (L.) Godron were induced by seven long days, then exposed to darkness for 48 h before being returned to short days, they went on to initiate flowers with a delay of about 2 d. The synchronisation of cell division which normally occurs before flower initiation was suppressed, showing that it is not essential for flowering. Periods of darkness of up to 240 h inhibited apical growth and leaf initiation but did not prevent eventual flowering in short days. The commitment of the apex to flower was therefore maintained while apical growth was inhibited.Abbreviations SD short day(s) - LD long day(s)     

Pollen vigour and composition in relation to andromonoecy in cashew (Anacardium occidentale L.: Anacardiaceae)

Summary Cashew trees produce four types of pollen from the large and small stamens of the hermaphrodite and male flower (HL, HS, ML, MS). Comparative studies were made of the grain number, structure, viability, vigour, and sugar and amino acid composition of the four pollen types. Anther and pollen grain numbers and dimensions of the four pollen types were similar, as were pollen structure and staining characteristics. The fluorescein diacetate test showed that the HL pollen had the highest percent fluorescence, and viability of all pollen types had declined by 48 h after anthesis. Following controlled hand pollination, the ML pollen had the highest capacity to germinate on the stigma and penetrate the ovule, followed by the MS, HL, and HS pollens. Glucose and fructose and 19 free amino acids were present in all pollen types, with higher levels in the hermaphrodite than in the male flower pollen. The results indicate that the pollen of the male flower is specialised for pollination and fruit set, whereas that of the hermaphrodite flower may be specialised for insect attraction.     

湿地植物大花百合种群的性系统特征

开花植物性系统特征是植物在长期适应进化过程中逐渐形成的繁殖策略, 它在一定程度上影响了物种的种群结构及其在生境中的分布格局, 因此性系统特征一直是植物进化与生态学领域的研究热点。本研究于2012年和2020年在吉林省金川泥炭沼泽湿地, 通过样地调查取样的方法, 研究了湿地植物大花百合(Lilium concolor var. megalanthum)的性系统特征以及不同性别表型植株的比例、密度及空间分布格局, 并探究了大花百合植株个体大小和其性别表达的联系, 比较了不同性别表型的花粉实际可育性和来源不同的花粉授粉处理结实后的种子活力。结果显示, 个体水平上, 大花百合具有雄花植株、两性花植株和雄花两性花同株(即雄全同株) 3种性表型; 种群水平上, 具有雄花的个体充当父本, 通过花粉向下一代传递基因, 而具有两性花的个体主要充当母本, 通过胚珠实现基因的传递。2020年大花百合雄花植株占种群内开花植株的39.14%, 相比2012年雄花植株比例增加了22.80%; 大花百合种群分布密度为0.06株/m², 较2012年下降了0.09株/m²。从2012年到2020年, 总体表现为种群密度降低, 雄花植株相对比例增加的趋势。两性花植株和雄花植株在小尺度范围主要呈聚集分布, 随着尺度增大, 趋于随机分布。雄花植株显著小于两性花植株, 但鳞茎资源分配显著高于两性花植株。大花百合植株的性表达遵循大小依赖的性分配假说: 个体较小的植株表达为雄花植株, 而个体较大的植株则为两性花植株或雄全同株。在不同授粉处理下的结籽率和种子萌发结果表明, 大花百合自花授粉结籽率和坐果率显著低于异花授粉, 雄花植株和两性花植株花粉可育性以及对两性花植株授粉后所获得种子活力无显著差异。大花百合雄花植株的出现可能是对有限环境资源条件适应的结果, 反映了湿地条件下该植物在生长和繁殖资源之间的权衡策略, 在长期的湿地演变过程中, 这种性系统特征的出现具有一定的适应性意义。     

Gynodioecy in Cirsium chikushiense Koidz. (Compositae)

A study of the morphology and function of flowers in Cirsiumchikushiense revealed that the species was distinctly gynodioecious.Self-incompatible hermaphrodite florets produced both seedsand pollen grains, while female ones produced seeds but no pollengrains at all. The degenerated stamens of females were not onlysmaller but also sometimes occurred at a lower position insidethe floral tube than in hermaphrodites. The stigmata of femalesoften developed more fully than those of hermaphrodites. Thefrequencies of female plants in natural populations varied from15·5 to 50%. Almost all the pollinators stayed on bothfemale and hermaphrodite heads only to collect nectar. The femaleplants of this species may be more specialized in their genderby saving the cost of not only pollen grains but also stamens,and may be maintained by sufficient pollinators in natural populations.This gynodioecy may provide an example of nuclear-cytoplasmicmale sterility.Copyright 1994, 1999 Academic Press Sex expression, gynodioecy, Cirsium chikushiense, Compositae, male sterility, degenerated stamen, female frequency