诱导风信子（Hyacinthus orientalis L.）同一花被外植体不同部位细胞分化花芽的研究--外源激素的作用及内源激素的变化

诱导风信子（Hyacnthus orientalis L．）同一花被外植体上不同部位细胞分化花芽，从外源激素的作用和内探激素的变化探讨细胞脱分化启动的原因，研究了不同外源激素的组合下同一花被不同部位花芽分化的诱导频率：测定了花被上、中，下三部位切块离体培养前后的内源IAA和Z+ZR的含量;在此之前研究了GC-MS．MIM内标法测定微量植物材料内源IAA含量的可行性． GC-MS．MIM内标法是测定微量（0.5-1g）植物材料内源IAA含量的一种比较理想的方法，所需材料量一般为0.58．这一方法的材料前处理采用粗提液用C18Sep-pak柱初步分离纯化．HPLC进一步纯化，能获得纯度高的样品，且操作简便，省时省力． 风信子同一花被不同部位细胞均能分化花芽．当培养基中附加2.0mg/l Zeatin或2.0mg/16-BAP时，随着外探IAA浓度从0升高到10.0mg/l．捆胞分化花芽的部位从花被下部向上部移动。 离体培养前后同一花被上、中、下三部位内源IAA和Z+ZR含量测定结果表明．风信子同一花被内源IAA含量是上部最高，下部次之，中部最低，而内源Z+ZR含量从上向下依次增加;在附加不同外源激素的MS培养基上培养3天后，同一花被上，中、下三部位内源IAA和Z+ZR含量部有一定的变化。

Iniciação floral e ácido giberélico no florescimento e na produção da lima ácida 'Tahiti' (Citrus latifolia, Tanaka)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Regulation of strawberry growth and development

Strawberries (Fragaria sp.) are adapted to diverse environmental conditions from the tropics to about 70ºN, so different responses to environmental conditions can be found. Most genotypes of garden strawberry (F. x ananassa Duch.) and woodland strawberry (F. vesca L.) are short-day (SD) plants that are induced to flowering by photoperiods under a critical limit, but also various photoperiod x temperature interactions can be found. In addition, continuously flowering everbearing (EB) genotypes are found. In addition to flowering, axillary bud differentiation in strawberry is regulated by photoperiod. In SD conditions, axillary buds differentiate to rosette-like structures called "branch crowns", whereas in long-day conditions (LD) they form runners, branches with 2 long internodes followed by a daughter plant (leaf rosette). The number of crown branches determines the yield of the plant, since inflorescences are formed from the apical meristems of the crown. Although axillary bud differentiation is an important developmental process in strawberries, its environmental and hormonal regulation has not been characterized in detail. Moreover, the genetic mechanisms underlying axillary bud differentiation and regulation of flowering time in these species are almost completely unresolved. These topics have been studied in this thesis in order to enhance strawberry research, cultivation and breeding. The results showed that 8-12 SD cycles suppressed runner initiation from the axillary buds of the garden strawberry cv. Korona with the concomitant induction of crown branching, and 3 weeks of SD was sufficient for the induction of flowering in the main crown. Furthermore, a second SD treatment given a few weeks after the first SD period can be used to induce flowering in the primary branch crowns and to induce the formation of secondary branches. Thus, artificial SD treatments effectively stimulate crown branching, providing one means for the increase of cropping (yield) potential in strawberry. It was also shown by growth regulation applications, quantitave hormone analysis and gene expression analysis that gibberellin (GA) is one of the key signals involved in the photoperiod control of shoot differentiation. The results indicate that photoperiod controls GA activity specifically in axillary buds, thereby determining bud fate. It was further shown that chemical control of GA biosynthesis by prohexadione-calcium can be utilized to prevent excessive runner formation and induce crown branching in strawberry fields. Moreover, ProCa increased berry yield up to 50%, showing that it is an easier and more applicable alternative to artificial SD treatments for controlling strawberry crown development and yield. Finally, flowering gene pathways in Fragaria were explored by searching for homologs of 118 Arabidopsis thaliana flowering-time genes. In total, 66 gene homologs were identified, and they distributed to all known flowering pathways, suggesting the presence of these pathways also in strawberry. Expression analysis of selected genes revealed that the mRNA of putative floral identity gene APETALA1 accumulated in the shoot apex of the EB genotype after the induction of flowering, whereas it was absent in vegetative SD genotype, indicating the usefulness of this gene product as the marker of floral initiation. The present data enables the further exploration of strawberry flowering pathways with genetic transformation, gene mapping and transcriptomics methods.

Boron deficiency inhibits petiole and peduncle cell development and reduces growth of cotton

The effect of boron (B) on cotton growth and fruit shedding may be due not only to physiological or biochemical effects, but also to vascular tissue malformation. This experiment investigated petiole and floral peduncle anatomical alterations and growth of cotton supplied with deficient and sufficient B in nutrient solution. Cotton (Gossypium hirsutum cv. 'Delta Opal') plants were grown in solutions containing 0, 1.5, 3.0, 4.5, and 6.0 mu mol L-1 of B from 22 to 36 d after plant emergence (DAPE). From 36 to 51 DAPE, B was omitted from the nutrient solution. Petioles from young leaves and floral bud peduncles (first position of the first sympodial) were sampled and the cross-section anatomy observed under an optical microscope. The number of vascular bundles of the petiole was decreased in B-deficient plants and the xylem was disorganized. Phloem elements in the peduncle vascular cylinder of B-deficient plants did not show clear differentiation. The few xylem elements that were formed were also disorganized. Modifications caused by B deficiency may have impaired B and photosynthate translocation into new cotton growth. Boron accumulation in the shoot of B-deficient plants suggested that there was some B translocation within the plant. It could be inferred that cotton growth would be impaired by the decrease in carbohydrate translocation rather than by B deficiency in the tissue alone.

Structure and ontogeny of Swartzia langsdorffii (Leguminosae) pericarp

In order to elucidate the position of the Swartzieae in Leguminosae, Swartzia langsdorffii was chosen as a representative of this tribe type genus and subjected to structural studies of immature ovaries (in the floral bud and flowers) and developing and mature fruits. The external epidermis of the ovary is characterized by one layer of thin-walled polyhedral cells with a thin cuticle. Parenchyma cells have a large quantity of tannin-containing idioblasts located inside a procambial ring. The one-layered inner epidermis consists of flattened cells. In fruits the one-layered exocarp is covered by a thick cuticle. The mesocarp consists of three distinct regions, the middle region being a sclerenchymatous layer. The one-layered endocarp shows cells with little cohesion. The occurrence of canals consisting of a net of resinous cells was also observed in the mesocarp. Secretion was of an elaborate composition. Differentiation of the secretory structures begin in the floral bud ovary, where they appear as idioblasts containing tannin. The taxonomic position of this tribe, as well as the function of the mesocarp secreting canals, are discussed.

Novel Features of the Prenatal Horn Bud Development in Cattle (Bos taurus).

Whereas the genetic background of horn growth in cattle has been studied extensively, little is known about the morphological changes in the developing fetal horn bud. In this study we histologically analyzed the development of horn buds of bovine fetuses between ~70 and ~268 days of pregnancy and compared them with biopsies taken from the frontal skin of the same fetuses. In addition we compared the samples from the wild type (horned) fetuses with samples taken from the horn bud region of age-matched genetically hornless (polled) fetuses. In summary, the horn bud with multiple layers of vacuolated keratinocytes is histologically visible early in fetal life already at around day 70 of gestation and can be easily differentiated from the much thinner epidermis of the frontal skin. However, at the gestation day (gd) 212 the epidermis above the horn bud shows a similar morphology to the epidermis of the frontal skin and the outstanding layers of vacuolated keratinocytes have disappeared. Immature hair follicles are seen in the frontal skin at gd 115 whereas hair follicles below the horn bud are not present until gd 155. Interestingly, thick nerve bundles appear in the dermis below the horn bud at gd 115. These nerve fibers grow in size over time and are prominent shortly before birth. Prominent nerve bundles are not present in the frontal skin of wild type or in polled fetuses at any time, indicating that the horn bud is a very sensitive area. The samples from the horn bud region from polled fetuses are histologically equivalent to samples taken from the frontal skin in horned species. This is the first study that presents unique histological data on bovine prenatal horn bud differentiation at different developmental stages which creates knowledge for a better understanding of recent molecular findings.

Seasonal effects of foliar application of phosphonate on phosphonate translocation, in vitro pollen viability and pollen germination in `Hass' avocado (Persea americana Mill.)

Phosphonate fungicides are used widely in the control of diseases caused by Phytophthora cinnamomi Rands. For the most part phosphonate is seen as a safe to use on crops with phytotoxicity rare. However, recent research has shown that phosphonate has detrimental effects on the floral biology of some indigenous Australian plants. Since phosphonate fungicides are regularly used for the control of Phytophthora root rot in avocados, research was carried out to study the translocation of phosphonate fungicide in 'Hass' trees and any effects on their floral biology. Field-grown trees were sprayed with 0, 0.06 or 0.12 M mono-dipotassium phosphonate (pH 7.2) at summer flush maturity, floral bud break or anthesis. Following treatment, phosphonic acid concentrations were determined in leaves, roots, inflorescence rachi and flowers and in vitro pollen germination and pollen tube growth studied. Phosphonic acid concentration in the roots and floral parts was related to their sink strength at the respective times of application with concentration in roots highest (36.9.mg g±1) after treatment at summer flush maturity and in flowers (234.7 mg g±1) after treatment during early anthesis. Phosphonate at >0.03 M was found to be significantly phytotoxic to in vitro pollen germination and pollen tube growth. However, this rate gave a concentration far in excess of that measured in plant tissues following standard commercial applications of mono-dipotassium phosphonate fungicide. There was a small effect on pollen germination and pollen tube growth when 0.06 and 0.12 M mono-dipotassium phosphonate was applied during early anthesis. However, under favourable pollination and fruit set conditions it is not expected to have commercial impact on tree yield. However, there may be detrimental commercial implications from phosphonate sprays at early anthesis if unfavourable climatic conditions for pollination and fruit set subsequently occur. A commercial implication from this study is that phosphonic acid root concentrations can be elevated and maintained with strategic foliar applications of phosphonate fungicide timed to coincide with peaks in root sink strength. These occur at the end of the spring and summer flushes when shoot growth is relatively quiescent. Additional foliar applications may be advantageous in under high disease-pressure situations but where possible should be timed to minimize overlap with other significant growth events in the tree such as rapid inflorescence, and fruit development and major vegetative flushing.

Modelling temperature, photoperiod and vernalization responses of Brunonia australis (Goodeniaceae) and Calandrinia sp (Portulacaceae) to predict flowering time

Crop models for herbaceous ornamental species typically include functions for temperature and photoperiod responses, but very few incorporate vernalization, which is a requirement of many traditional crops. This study investigated the development of floriculture crop models, which describe temperature responses, plus photoperiod or vernalization requirements, using Australian native ephemerals Brunonia australis and Calandrinia sp. A novel approach involved the use of a field crop modelling tool, DEVEL2. This optimization program estimates the parameters of selected functions within the development rate models using an iterative process that minimizes sum of squares residual between estimated and observed days for the phenological event. Parameter profiling and jack-knifing are included in DEVEL2 to remove bias from parameter estimates and introduce rigour into the parameter selection process. Development rate of B. australis from planting to first visible floral bud (VFB) was predicted using a multiplicative approach with a curvilinear function to describe temperature responses and a broken linear function to explain photoperiod responses. A similar model was used to describe the development rate of Calandrinia sp., except the photoperiod function was replaced with an exponential vernalization function, which explained a facultative cold requirement and included a coefficient for determining the vernalization ceiling temperature. Temperature was the main environmental factor influencing development rate for VFB to anthesis of both species and was predicted using a linear model. The phenology models for B. australis and Calandrinia sp. described development rate from planting to VFB and from VFB to anthesis in response to temperature and photoperiod or vernalization and may assist modelling efforts of other herbaceous ornamental plants. In addition to crop management, the vernalization function could be used to identify plant communities most at risk from predicted increases in temperature due to global warming.

Regeneration of plantlets from leaf disc cultures of rosewood: control of leaf abscission and shoot tip necrosis

A method for mass production of rosewood (Dalbergia latifolia Roxb.) trees through leaf disc organogenesis was developed and standardized. Compact callus was initiated from mature leaf discs on Murashige and Skoog (MS) basal medium supplemented with 1.0 mg 1?1 2,4-dichlorophenoxy acetic acid (2,4-D), 5.0 mg 1?1 ?-naphthaleneacetic acid (NAA), 1.0 mg 1?1 6-benzylaminopurine (BAP) and 10% coconut water (CW). High frequency (15�20 shoots/g callus) regeneration of shoot bud differentiation was obtained on MS (3/4 reduced major elements) or Woody Plant Medium (WPM) or modified Woody Plant Medium (mWPM) supplemented with BAP (5.0 mg 1?1) and NAA (0.5 mg 1?1). Leaf abscission and shoot tip necrosis was controlled using mWPM. About 90% of the excised shoots were rooted in the mWPM supplemented with 2.0 mg 1?1 ?-indolebutyric acid (IBA) and 1.0 mg 1?1 caffeic acid. The in vitro-raised rooted plantlets were hardened for successful transplantation to soil. The transplanted plants were exposed to various humidity conditions and 80% transplant success was achieved. The in vitro-raised leaf-regenerated plants grew normally and vigorously in soil.

Composition of Extrafloral Nectar Influences Interactions between the Myrmecophyte Humboldtia brunonis and its Ant Associates

Ant-plant interactions often are mediated by extrafloral nectar (EFN) composition that may influence plant visitation by ants. Over a 300 km range in the Indian Western Ghats, we investigated the correlation between the EFN composition of the myrmecophytic ant-plant Humboldtia brunonis (Fabaceae) and the number and species of ants visiting EFN. EFN composition varied among H. brunonis populations and between plant organs (floral bud vs. young leaf EFN). In general, EFN was rich in sugars with small quantities of amino acids, especially essential amino acids, and had moderate invertase activity. In experiments at the study sites with sugar and amino acid solutions and with leaf or floral bud EFN mimics, dominant EFN-feeding ants differentiated between solutions as well as between mimics. The castration parasite Crematogaster dohrni (northern study site) was the least selective and did not exhibit any clear feeding preferences, while the largely trophobiont-tending non-protective Myrmicaria brunnea (middle study site) preferred higher sucrose concentrations and certain essential/non-essential amino acid mixtures. The mutualistic Technomyrmex albipes (southern study site) preferred sucrose over glucose or fructose solutions and consumed the leaf EFN mimic to a greater extent than the floral bud EFN mimic. This young leaf EFN mimic had low sugar concentrations, the lowest viscosity and sugar: amino acid ratio, was rich in essential amino acids, and appeared ideally suited to the digestive physiology of T. albipes. This preference for young leaf EFN may explain the greater protection afforded to young leaves than to floral buds by T. albipes, and may also help to resolve ant-pollinator conflicts. The differential response of dominant ants to sugar, amino acids, or solution viscosity suggests that plants can fine-tune their interactions with local ants via EFN composition. Thus, EFN can mediate local partner-choice mechanisms in ant-plant interactions.

牡丹花芽分化类型与促成连续二次开花

牡丹（Paeonia suffruticosa Andr.），芍药科芍药属植物，是我国的传统名花，因花朵硕大、花色丰富、花型齐全而显雍容华贵、富丽端庄，“惟有牡丹真国色，花开时节动京城”，深受人民的喜爱。人们在欣赏牡丹的过程中，一方面为其艳丽多姿而赞叹，同时又为其自然花期较短且集中而遗憾，“弄花一年，看花十日”，因此，如何通过栽培等技术措施使牡丹连续开花，一直是牡丹研究者探索的重要课题。近年，在对牡丹栽培的系统研究中，发现不同牡丹品种的花芽分化类型（数量、梯度）直接影响其开花数量和开花次数。为了有效地利用不同类型的牡丹，选育出更多的丰花、同株可连续开花的品种，服务于牡丹的产业化生产，本试验对4个牡丹品种群的135个品种进行了同枝条芽数的统计分析及花芽分化梯度的划分，阐明了花芽分化类型与促成连续二次开花的关系。初步测定了具有促成连续二次开花习性的牡丹品种‘High Noon’不同芽位腋芽内源激素的含量，揭示了牡丹同株连续二次开花过程中不同芽位腋芽内源激素的生理变化规律，为解决牡丹同株花期短、不能同株连续开花的难题奠定了理论基础。本研究主要结果如下： 1、牡丹花芽分化类型与自然开花的关系 通过对135个牡丹品种花芽分化数量和梯度类型的调查，将同枝条的芽数聚类为少（3-4）、中等（5-7）、多（8-10）三类;将花芽分化梯度划分为小、中、大三种类型。芽数类型和花芽分化梯度类型均与品种群有一定的关系。中原品种群中90%的品种属于芽数少的类型，47%的品种属于分化梯度大的类型;日本品种群中73%的品种属于芽数中等的类型，52%的品种属于分化梯度中的类型;法国品种群和美国品种群品种调查数量较少，但大多数品种属于芽数中等的类型，分别占80%和44%，分化梯度小的品种分别占调查总数的40%和67%。绝大部分品种的腋花芽因在枝条上着生的位置不同而有明显的异质性，上部芽顶端优势强，萌动率和开花率均高，芽数多的品种中、下部芽在春天自然开花季节常处于休眠状态。 2、牡丹花芽分化类型与促成连续二次开花的关系 花芽分化数量的多少与梯度的大小直接影响着开花次数。花芽分化数量少、梯度大的品种不建议直接用于同株促成连续二次开花栽培;花芽分化数量中等或多、梯度小的品种可以实现同株促成连续二次开花，10个试验牡丹品种中的中原牡丹品种‘如花似玉（Ru Hua Si Yu）’和美国牡丹品种‘High Noon’具有同株连续二次开花能力，且二次开花率达75%以上，两次开花品质均优良。 3、‘High Noon’不同芽位腋芽内源激素与促成连续开花的关系 通过测定美国牡丹品种‘High Noon’同枝条不同芽位腋芽萌动前期、后期内源激素含量，结果表明：萌动后期不同芽位腋芽的GA3、IAA、ZRs含量增加，尤其1位芽、2位芽含量增加显著;萌动后期ABA含量则随着芽位自上而下增加显著，可能是导致下部芽继续保持休眠状态的主要原因;萌动后期下部芽的ABA/ZRs配比增幅较高，说明ABA/ZRs配比与芽的生长与休眠关系密切。

Ethylene and polyamine production patterns during in vitro shoot organogenesis of two passion fruit species as affected by polyamines and their inhibitor

Levels of ethylene and polyamines (PAs) were measured during organogenesis of hypocotyl explants of two species of passion fruit (Passiflora cincinnata Masters and Passiflora edulis Sims f. flavicarpa Degener `FB-100`) to better understand the relationships of these regulators and their influence on cell differentiation and morphogenesis. Moreover, histological investigation of shoot ontogenesis was conducted to characterize the different events involved in cell redifferentiation and regulation of PA and ethylene levels. A delay was observed in morphogenic responses of P. edulis f. flavicarpa as compared to P. cincinnata, and these changes coincided with production of elevated levels of polyamine and ethylene levels. During differentiation, cells showed high rates of expansion and elongation, and high ethylene levels were associated with high PA levels, suggesting that the two biosynthesis pathways were highly regulated. Moreover, their interaction might be an important factor for determining cell differentiation. The addition of PAs to the culture medium did not promote organogenesis; however, the incorporation of the PA inhibitor methylglyoxal bisguanylhydrazone in the culture medium reduced shoot bud differentiation, suggesting the need to maintaining a minimum level of PAs for morphogenic events to take place.

Morfoanatomia e ontogênese do fruto e semente de Styrax camporum Pohl. (Styracaceae), espécie de cerrado do Estado de São Paulo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Entomofauna visitante de Belamcanda chinensis (L.) DC (Iridaceae) durante o período de floração

A study of the reproductive biology of B. chinensis (L.) DC. (Iridaceae) was realized comprising floral biology and breeding systems. The floral biology studies included analyses of nectar production, occurence of osmophores, corolla pigments, ultraviolet reflexion and absortion patterns, viability of pollen, pollinators and flower visitors. The breeding systems were studied taking into account the results of manual pollinators tests. B. chinensis is self-compatible bul cross-pollination is more frequent. The effective pollinators are Plebeia droryana (Friese, 1906) (45,7%), Trigona spinipes (Fabricius, 1793) (27,3%), Tetragonisca angustula (Latreille, 1811) (9,3%). Others insects visitors are considered nectar and pollen thieves. The flowering begins generally in January and February. The complete reproductive cicle, as here considered, begining with floral bud production ending with development of mature fruits, lasts January to June. Seed dispersion is ornitocoric.