《植物名实图考》中一些百合科植物考证兼论茄子在中国的栽培起源和传播——植物考据学个例研究

中国古代涉及植物学的文献可谓浩如烟海。由于中国植物种类繁多，加之方言的分化和文字的演变，古籍文献中的植物名称难以计数。距古愈久，失误愈多，渐至名称混乱难以分辨，同物异名、同名异物现象比比皆是。植物考据在这样的背景下产生了。本文确立了中国植物考据研究的范围、内容、证据、方法和目的，并以时间为线索，梳理了中国植物考据研究两千多年的历史，扼要评介了各个历史阶段的代表人物及作品。在此基础上，本文遵循“由近及远，先实后虚”的研究思路，考证了《植物名实图考》的几种百合科植物，同时选定茄子这一栽培植物，以它为点，利用中国古籍文献证据，研究它在中国的起源、驯化和传播，藉此探讨植物考据研究所能解决的植物学问题。 1. 粉条儿菜和肺筋草考 理清了近百年来“粉条儿菜”和“肺筋草”这两个植物中文名称的混乱，确认粉条儿菜一名最早见于《救荒本草》，实为菊科Compositae鸦葱属Scorzonera华北鸦葱Scorzonera albicaulis;首次记载于《植物名实图考》中的“肺筋草”才是Aletris 属植物，应为Aletris scopulorum，非前人考证的Aletris spicata。 2. 黄精属植物考 《图考》“黄精”包括了多花黄精Polygonatum cyrtonema、长梗黄精P. filipes和距药黄精P. franchetii，这三个种实际上是一个集合种 (species aggregate), 即使用现代分类的观点来看，它们之间也很难从外部形态区分开来;“黄精苗”可能为P. sibiricum或P. verticillatum;认为“滇钩吻（一）”应为点花黄精P. punctatum，这与前人的考证结果相同;“滇钩吻（二）”和“滇黄精”可能分别为卷叶黄精P. cirrhifolium和滇黄精P. kingianum中的某个种，但限于黄精属植物分类研究的程度，暂且存疑;“萎蕤”图所绘植物不属于黄精属Polygonatum，而为万寿竹属Disporum的横脉万寿竹D．trabeculatum。 3. 贝母考 《图考》贝母条下所附贝母图，不属于贝母属Fritillaria植物，而属天南星科Araceae，可能为半夏Pinellia ternata的幼苗;文中“点苍山生者”可能是鸭趾草科蓝耳草Cyanotis vaga;“张子诗”中的蔓生贝母为Bolbostemma paniculatum，这可能是中国古代最早利用的“贝母”，后来逐渐被Fritillaria属植物替代。 4. 茄子的栽培起源和传播 本文首先借助于现代系统学和遗传学的研究结果，理清茄子及其近缘种的分类、地理分布和可能的驯化过程;结合民族植物学研究和大量的野外考察，确认了茄子及其近缘种在中国的形态、分布和利用方法等等;而后将今论古，用严格的考据方法理清在浩如烟海的中国古籍文献中与茄子相关文献的科学含义。在这个基础上推演茄子在中国栽培起源和传播的途径。得到以下结论：茄子的野生种GroupF和原始栽培种Group G在中国南方热带地区存在，早在晋代记载的“茄树”很可能就是这个原始栽培种Group G;高级栽培种Group H最早在公元前一世纪就有记载，有可能在中国四川盆地南部山区的暖温带地区被首先驯化;中国有些茄子的高级栽培种Group H也有可能从印度传来，但传播路线应该是沿着由南向北的西南丝绸之路，而非如一些学者所认为的自西向东由西北丝绸之路首先传入长安;在中国，茄子的高级栽培种由成都平原向长江中下游地区传播，继而在公元五到六世纪传播到黄河中下游地区，栽培技术已经成熟，利用方法越来越多, 到了宋代已经遍布整个中国;茄子在中国的选育是向着果实体积变大、味道变甜的方向进行, 宋代茄子发生了明显的品种分化，出现了世界上最早的茄子图。

Sexual selection in a tropical fruit fly : role of a plant derived chemical in mate choice

The specific mechanisms by which selective pressures affect individuals are often difficult to resolve. In tephritid fruit flies, males respond strongly and positively to certain plant derived chemicals. Sexual selection by female choice has been hypothesized as the mechanism driving this behaviour in certain species, as females preferentially mate with males that have fed on these chemicals. This hypothesis is, to date, based on studies of only very few species and its generality is largely untested. We tested the hypothesis on different spatial scales (small cage and seminatural field-cage) using the monophagous fruit fly, Bactrocera cacuminata. This species is known to respond to methyl eugenol (ME), a chemical found in many plant species and one upon which previous studies have focused. Contrary to expectation, no obvious female choice was apparent in selecting ME-fed males over unfed males as measured by the number of matings achieved over time, copulation duration, or time of copulation initiation. However, the number of matings achieved by ME-fed males was significantly greater than unfed males 16 and 32 days after exposure to ME in small cages (but not in a field-cage). This delayed advantage suggests that ME may not influence the pheromone system of B. cacuminata but may have other consequences, acting on some other fitness consequence (e.g., enhancement of physiology or survival) of male exposure to these chemicals. We discuss the ecological and evolutionary implications of our findings to explore alternate hypotheses to explain the patterns of response of dacine fruit flies to specific plant-derived chemicals.

Influence of host plant structure and microclimate on the abundance and behaviour of Tephritid fly

Microclimate and host plant architecture significantly influence the abundance and behavior of insects. However, most research in this field has focused at the invertebrate assemblage level, with few studies at the single-species level. Using wild Solanum mauritianum plants, we evaluated the influence of plant structure (number of leaves and branches and height of plant) and microclimate (temperature, relative humidity, and light intensity) on the abundance and behavior of a single insect species, the monophagous tephritid fly Bactrocera cacuminata (Hering). Abundance and oviposition behavior were signficantly influenced by the host structure (density of foliage) and associated microclimate. Resting behavior of both sexes was influenced positively by foliage density, while temperature positively influenced the numbers of resting females. The number of ovipositing females was positively influenced by temperature and negatively by relative humidity. Feeding behavior was rare on the host plant, as was mating. The relatively low explanatory power of the measured variables suggests that, in addition to host plant architecture and associated microclimate, other cues (e.g., olfactory or visual) could affect visitation and use of the larval host plant by adult fruit flies. For 12 plants observed at dusk (the time of fly mating), mating pairs were observed on only one tree. Principal component analyses of the plant and microclimate factors associated with these plants revealed that the plant on which mating was observed had specific characteristics (intermediate light intensity, greater height, and greater quantity of fruit) that may have influenced its selection as a mating site.

Somatic embryogenesis, organogenesis and plant regeneration in taro (Colocasia esculenta var. esculenta)

Callus was initiated in three different ‘‘esculenta’’ taro cultivars by culturing corm slices in the dark on half-strength MS medium supplemented with 2.0 mg/l 2,4- dichlorophenoxyacetic acid (2,4-D) for 20 days followed by subculture of all corm slices to half-strength MS medium containing 1.0 mg/l thidiazuron (TDZ). Depending on the cultivar, 20–30% of corm slices produced compact, yellow, nodular callus on media containing TDZ. Histological studies revealed the presence of typical embryogenic cells which were small, isodiametric with dense cytoplasms. Somatic embryos formed when callus was transferred to hormone-free medium and *72% of the embryos germinated into plantlets on this medium. Simultaneous formation of roots and shoots during germination, and the presence of shoot and root poles revealed by histology, confirmed that these structures were true somatic embryos. Plants derived from somatic embryos appeared phenotypically normal following 2 months growth in a glasshouse. This method is a significant advance on those previously reported for the esculenta cultivars of taro due to its efficiency and reproducibility.

Initiation of embryogenic cell suspensions of taro (Colocasia esculenta var. esculenta) and plant regeneration

Embryogenic callus was initiated by culturing in vitro taro corm slices on agar-solidified half-strength MS medium containing 2.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) for 20 days followed by transfer to 1.0 mg/L thidiazuron (TDZ). Callus was subsequently proliferated on solid medium containing 1.0 mg/L TDZ, 0.5 mg/L 2,4- D and 800 mg/L glutamine before transfer to liquid medium containing the same components but with reduced glutamine (100 mg/L). After 3 months in liquid culture on an orbital shaker, cytoplasmically dense cell aggregates began to form. Somatic embryogenesis was induced by plating suspension cells onto solid media containing reduced levels of hormones (0.1 mg/L TDZ, 0.05 mg/L 2,4-D), high concentrations of sucrose (40–50 g/L) and biotin (1.0 mg/L). Embryo maturation and germination was then induced on media containing 0.05 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-acetic acid (IAA). Histological studies of the developing embryos revealed the presence of typical shoot and root poles suggesting that these structures were true somatic embryos. The rate of somatic embryos formation was 500–3,000 per mL settledcell volume while approximately 60% of the embryos regenerated into plants.

A cost-based optimization of a fiberboard pressing plant using Monte-Carlo simulation (a reliability program)

In this research the reliability and availability of fiberboard pressing plant is assessed and a cost-based optimization of the system using the Monte- Carlo simulation method is performed. The woodchip and pulp or engineered wood industry in Australia and around the world is a lucrative industry. One such industry is hardboard. The pressing system is the main system, as it converts the wet pulp to fiberboard. The assessment identified the pressing system has the highest downtime throughout the plant plus it represents the bottleneck in the process. A survey in the late nineties revealed there are over one thousand plants around the world, with the pressing system being a common system among these plants. No work has been done to assess or estimate the reliability of such a pressing system; therefore this assessment can be used for assessing any plant of this type.