Allometry of within-fruit reproductive allocation in subtropical dicot woody species

Angiosperm fruits typically consist of pericarp and seed, which collectively function to maximize plant reproductive success. Within-fruit reproductive allocation has been scarcely examined across a wide range of fruit types and taxa although it is critical to the understanding of the evolution of fruit size and seed size. We investigated seed size, fruit size, seed number per fruit (SNF), and within-fruit biomass allocation between seed mass and pericarp mass for 62 dicot woody species (27 deciduous and 35 evergreen species) of a subtropical evergreen forest in southwest China. At the fruit level, total pericarp mass (TPM) isometrically scaled with increasing total seed mass (TSM) in the evergreen species and in the pooled data set, while TPM increased faster than TSM in the deciduous species. The slope difference is possibly due to the difference in the timing of fruit development between the two species groups. At the seed level, seed package (pericarp mass per seed) isometrically scaled with increasing seed size in the deciduous group, but less than isometrically in the evergreens and in the pooled data set. SNF was negatively correlated with seed size but positively correlated with the proportion of pericarp within fruits. In conclusion, within-fruit biomass allocation is significantly affected by seed size, fruit size, and SNF in both deciduous and evergreen species. The implications of the observed scaling relationships are discussed in relation to seed size evolution and global patterns of seed size variation.     

狗枣猕猴桃果实发育的解剖学观察

对狗枣猕猴桃果实发育进行了显微和超微结构观察。其主要过程可分为：1. 早期胚胎发育：多心皮合生子房,通常具16个心室,中轴胎座。中轴上着生大量倒生胚珠,单珠被,具珠被绒毡层。胚囊蓼型。授粉后约2～4h花粉萌发。授粉后约120h花粉管到达胚珠。受精后,初生胚乳核分裂先于合子。胚乳发育为细胞型。2. 果壁：果壁可分为果皮、果肉和果心三部分。果皮较薄,由2～3层薄壁细胞组成。外表面光滑无毛,但覆有角质层,气孔下陷,分布于其中。果肉的大部分由薄壁细胞组成,分大、小两种细胞 ,小细胞含较多淀粉粒,淀粉粒的水解是果实软化的原因之一。果肉薄壁组织细胞还含有叶绿体及两种异细胞,一种异细胞内含物为结晶,普遍存在;另一种含被番红染成红色的絮团状物。果心由维管束和薄壁细胞组成,维管束不发达。3. 种子：种皮外表面呈蜂窝状,种皮较硬,由两层细胞构成。线性直立胚,胚乳发达,主要贮藏物是蛋白质。     

Inheritance of egusi seed type in watermelon

An unusual seed mutant in watermelon (Citrullus lanatus var. lanatus) has seeds with a fleshy pericarp, commonly called egusi seeds. The origin of the phenotype is unknown, but it is widely cultivated in Nigeria for the high protein and carbohydrate content of the edible seeds. Egusi seeds have a thick, fleshy pericarp that appears during the second to third week of fruit development. We studied the inheritance of this phenotype in crosses of normal seeded Charleston Gray and Calhoun Gray with two plant introduction accessions, PI 490383w and PI 560006, having the egusi seed type. We found that the egusi seed type is controlled by a single recessive gene, and the symbol eg was assigned.     

Endogenous Levels of Phenolics in Tomato Fruit during Growth and Maturation

Changes in the metabolism of several types of phenolics in the pulp and pericarp of tomato (Lycopersicon esculentum) fruit var. Ailsa Craig and Pik-Red were related to the stage of development. The highest levels of chlorogenic acid were found in the pulp and pericarp at the earliest stage of fruit development, and quantities declined rapidly during fruit ripening. Levels of rutin, found only in the pericarp, followed a similar pattern of change. The p-coumaric acid conjugate of rutin was found in low levels through fruit growth and ripening. High levels of p-coumaric acid glucoside were detected in the pulp only as the fruit matured with no rapid decline in levels during ripening. The decline of chlorogenic acid and rutin levels during fruit ripening paralleled the decline in indole-3-acetic acid levels measured previously in the pericarp tissues of these two varieties of tomato fruit during maturation. These phenolics are among those that have been suggested as regulants of auxin metabolism. Received April 30, 1996; accepted December 26, 1996     

濒危植物凹叶厚朴种实特性

凹叶厚朴(Magnolia officinalis subsp.biloba)为中国二级保护植物。本文对该树种不同分布群体的种实性状进行了研究。结果表明:凹叶厚朴结实数量较少,平均结实3.19个;种实特征在不同种群间差异显著,其变异主要来源于单株间及单株内,其中果实性状的方差分量要大于种子性状,表明果实的性状较易受环境的影响;果实性状与郁闭度及土壤养分含量存在显著或极显著的相关性,种子宽与种子质量与海拔呈显著负相关,种子厚度与海拔呈极显著负相关,而与生境及土壤条件相关性并不明显。凹叶厚朴在野生状态下单株结实率低,单果出种率低是其濒危的重要原因之一。     

Centuries-Old Viable Fruit of Sacred Lotus Nelumbo nucifera Gaertn var. China Antique

During the Sino-Japanese conflict of the 1920s, Japanese botanist Ichiro Ohga was presented single-seeded fruit of Nelumbo nucifera var. China Antique collected by a local farmer from a dry lakebed in Northeast China (then, “Manchuria”). Ohga studied the fruit and published his findings. Years later, we tested the germination of Nelumbo fruit from the same locality. The oldest seed sprouted, having a germination time of ~3 days, was radiocarbon dated to be ~1300 years old. These cold- and drought-tolerant seeds exhibited shoot-before-root emergence and a primary green plumule capable of “dim-light” photosynthesis. Such traits and the notable long-term viability of the fruit spurred the interest of Ray Ming, University of Illinois that has now led to the sequencing of the Nelumbo genome. Analyses of this genome may provide insight into the biochemistry of Nelumbo on wax-biosynthesis genes, and application of aging-related thermostable proteins to the extension of seed-life and improvement of food quality of economic crops. Here, we review the history of these long-lived Nelumbo fruit, and their occurrence, discovery, collection, propagation, and methods of seedling care. The robust impermeable wax- and suberin-covered pericarp is a major factor contributing to their remarkable longevity. New findings are presented on the modern and 459- and 464-year-old pericarp anatomy, impermeability to water, and whole fruit and pericarp mechanical properties, and comparison of the mode of fruit weight-gain during imbibition and germination time relative to fruit maturity.     

Purine Alkaloids of the Fruits of Camellia sinensis L. and Coffea arabica L. during Fruit Development

The amounts of two purine alkaloids, caffeine and theobromine,in the fruit of tea (Camellia sinensis L.) increased markedlyduring the growing season until the fruit was full-ripened anddried. In the dry fruit, the pericarp contained the most alkaloids,but there were also considerable amounts in the seed coat and,to a lesser extent, the fruit stalk and the seed. The shed seedsalso contained significant amounts of the alkaloids, especiallyin the seed coats. In contrast with the dry fruit of tea, seedsand pericarp of coffee (Coffea arabica L.) fruit contained aconsiderable amount of caffeine and a small amount of theobromide.A small amount of theophylline was also present in the pericarpof the ripened fruit. Relationships between growth and purinealkaloid content in tea and coffee fruits and their roles duringseed formation are discussed. Camellia sinensis L., tea, Coffea arabica L., coffee, purine alkaloids, fruit development, seed, seed coat, caffeine, theobromine, theophylline     

黄连木果实中油体的发育

黄连木（Pistacia chinensis）是一种重要的木本油料植物,其果实中贮存着大量的油脂,这些油脂分子主要存在于果皮、种皮和胚的油体中。在光学显微镜下观察发现,果皮中油的积累开始于果实发育晚期,果皮开始变红时;种皮中油体的发育开始于果实发育早期;胚中油体的发育开始于球形胚时期。透射电子显微镜观察结果显示,种皮和胚中的油体形成于内质网,而果皮中的油体则分别由内质网、质体和液泡形成。尼罗红荧光标记显示,内质网形成的油体始终以独立单元的形式存在。种皮和胚中也贮藏蛋白体,但发育晚于油体。果皮、种皮和子叶中都贮存少量的淀粉粒。     

Phloem unloading in developing walnut fruit is symplasmic in the seed pericarp and apoplasmic in the fleshy pericarp

The sieve element-companion cell (SE-CC) complex of the sepal bundles feeding the fleshy pericarp of developing walnut (Juglans regia L.) fruit is structurally symplasmically isolated, but the SE-CC complex of the minor ventral carpellary bundles located in the seed pericarp and feeding the seed is structurally symplasmically connected to its adjacent parenchyma cells. 14C-autoradiography indicated that the phloem of both the sepal and carpellary bundles was functional for unloading. Confocal laser scanning microscopy imaging of carboxyfluorescein unloading showed that the dye is confined to the phloem strands of the sepal bundles in the fleshy pericarp, but released from the phloem strands of the minor ventral carpellary bundles into the surrounding parenchyma cells in the seed pericarp. A 60-kDa acid invertase was immunolocalized to the cell wall of SE-CC complex and parenchyma cells in both the fleshy and seed pericarp. These data provide clear evidence for an apoplasmic phloem unloading pathway in the fleshy pericarp and a predominant symplasmic phloem unloading pathway parallel with a possible apoplasmic path as suggested by the presence of the extracellular invertase in the seed pericarp. A model of complex phloem unloading pathways in developing walnut fruit has been proposed.     

A systematic histological study of palm fruits. III. Subtribe Iguanurinae (Arecaceae)

This study represents a preliminary sampling of the pericarp histology of the subtribe Iguanurinae (tribe Areceae, subfamily Arecoideae) of the family Arecaceae. At least one sample from each of the 27 recognized genera was examined and illustrated with a line drawing. This sampling serves to characterize fruit structure in the subtribe as a whole, to illustrate the diversity of pericarp adaptations found in the subtribe, to characterize the monotypic genera, to provide hypotheses about the characterization of the larger genera, and to test existing phylogenetic hypotheses about the Iguanurinae. There are no unique tissues present in the pericarp in this subtribe, but genera can be readily characterized by unique combinations and distributional patterns in common tissues. These patterns, and some prominent evolutionary trends, parallel those in related subtribes of Areceae, such as the Ptychospermatinae and Arecinae. Significant in this subtribe is variation in the distribution of tanniniferous cells, raphide-bearing cells and brachysclereids, in the sculpturing of the seed and the locular epidermis, in the thickness of the locular epidermis, in the thickness of the fibrous vascular bundle sheaths, and especially in the number, orientation and distribution of nonvascular fibrous bundles. One major trend is the formation of systems of separate fibrous bundles and their progressive displacement toward the outer layer of the fruit, where a complex exocarp may form. The diversity of pericarp structure in the Iguanurinae is far greater than in the two subtribes previously studied.     

Rhus coriaria var. zebaria (Anacaridaceae), a new variety from Iraq

Rhus coriaria var. zebaria from Duhok/Aqrae, Kurdistan, Iraq is described as a variety new to science. Field expeditions started in spring 2011, continued during 2012 and 2013 with the aim of collecting sumac specimens from different physiographic regions of Kurdistan, Iraq. A total of ten plants for each variety were sampled. An equal number of tagged herbarium specimens were prepared. The holotype was designated and deposited together with other herbarium specimens in the herbarium of the Faculty of Agriculture and Forestry, Univ. of Duhok. Morphological characters of the leaf, inflorescence, flowers, infructescence, and fruit were studied. The pH value of the pericarp in addition to the hilum length was measured. Results were compared with Rhus coriaria L. var. coriaria. The most distinctive feature of the new variety is the dull whitish brown color of the drupe pericarp of var. zebaria as compared to the reddish brown color of the drupe pericarp of var. coriaria. The whitish color of the drupes of var. zebaria, in combination with their larger size, represents diagnostic characters for distinguishing this variety. In contrast, most leaf characters are of little or no taxonomic value in this species. Only shape, apex and marginal teeths of the leaflets show minor differences for separating the two varieties. Female and male inflorescences and flowers characters show no significant differences. Both hilum length and pH value characters may be useful for taxonomic application if mean values are taken in consideration.     

Significance of achene characteristics and within-achene resource allocation in the germination strategy of tetraploid Aster pilosus var. pilosus (Asteraceae)

The interrelationships among achene weight, allocation to embryo and pericarp, and germination time were determined for 500 stratified achenes of tetraploid Aster pilosus Willd. var. pilosus. Only 52.6% of the achenes germinated. Germinated achenes were significantly heavier than ungerminated achenes. Germination time was independent of achene weight and embryo weight, but varied inversely with pericarp weight. Variable achene weight is evolutionarily advantageous. Heavy achenes are at an advantage in that their proportionately larger embryos and thinner pericarps facilitate germination, promoting competitive establishment of seedlings. Lighter achenes are also at an advantage through increased dispersibility, and their relatively thick pericarp provides a persistent seed bank. Evolutionary pressures presumably maintain the variability in achene weight of var. pilosus. These results are discussed in the context of the early midsuccessional ecology of var. pilosus.     

Fruit and seed ontogeny related to the seed behaviour of two tropical species of Caesalpinia (Leguminosae)

Caesalpinia echinata and C. ferrea var. ferrea have different seed behaviours and seed and fruit types. Comparison of the seed ontogeny and anatomy partly explained the differences in seed behaviour between these two species of Brazilian legumes; some differences were also related to fruit development. The seed coat in C. ferrea consisted of two layers of osteosclereids, as well as macrosclereids and fibres, to form a typical legume seed coat, whereas C. echinata had only macrosclereids and fibres. In C. echinata , the developing seed coat had paracytic stomata, a feature rarely found in legume seeds. These seed coat features may account for the low longevity of C. echinata seeds. The embryogeny was similar in both species, with no differences in the relationship between embryo growth and seed growth. The seeds of both species behaved as typical endospermic seeds, despite their different morphological classification (exendospermic orthodox seeds were described for C. echinata and endospermic orthodox seeds for C. ferrea ). Embryo growth in C. ferrea accelerated when the sclerenchyma of the pericarp was developing, whereas embryonic growth in C. echinata was associated with the conclusion of spine and secretory reservoir development in the pericarp. Other features observed included an endothelial layer that secreted mucilage in both species, a nucellar summit, which grew up into the micropyle, and a placental obturator that connected the ovarian tissue to the ovule in C. ferrea . © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 57–70.     

Growth and respiration patterns of snap bean fruits

The relationship of respiration and growth of seed, pericarp tissue and whole fruit of snap beans (Phaseolus vulgaris L.) was studied. The whole fruit exhibited an apparent climacteric type of respiration pattern. This pattern resulted from an increase in CO₂ production by the enlarging seed followed by a rapid decrease in CO₂ evolution by the pericarp tissue, and the pattern was not associated with any concomitant increase in ethylene production. Therefore, the apparent climacteric respiration pattern of a developing bean fruit is not comparable to the phenomenon that occurs in other ripening fruits.     

Hardness as a basis of fruit choice in two sympatric primates

Fruit color and size are significant determinants of food choice in mammals and birds, but hardness, an important physical property of fruit and seeds, has generally been overlooked as a determinant of food choice in studies of mammalian foraging behavior. Two methods were used to determine fruit hardness during a field study of two sympatric primates, the black spider monkey (Ateles paniscus) and the bearded saki monkey (Chiropotes satanas) in Surinam. We measured both puncture resistance of fruit pericarp and crushing resistance of seeds. Puncture resistance of the pericarp of some fruit opened by Chiropotes was as much as 15 times greater than that of all fruit successfully opened by Ateles. In contrast, crushing resistance of species of seeds masticated by Chiropotes was significantly lower than that of seeds swallowed by Ateles. These data demonstrate that hardness of both fruit pericarp and seed may play a significant role in food choice among sympatric vertebrates. Measurements of both puncture resistance of the pericarp and crushing resistance of the seed are necessary for understanding the significance of fruit hardness in these primates.     

Sucrose-to-Starch Metabolism in Tomato Fruit Undergoing Transient Starch Accumulation

Immature green tomato (Lycopersicon esculentum) fruits undergo a period of transient starch accumulation characterized by developmental changes in the activities of key enzymes in the sucrose (Suc)-to-starch metabolic pathway. Activities of Suc synthase, fructokinase, ADP-glucose (Glc) pyrophosphorylase, and soluble and insoluble starch synthases decline dramatically in parallel to the decrease in starch levels in the developing fruit. Comparison of "maximal" in vitro activities of the enzymes in the Suc-to-starch pathway suggests that these same enzymes are limiting to the rate of starch accumulation. In contrast, activities of invertase, UDP-Glc pyrophosphorylase, nucleoside diphosphate kinase, phosphoglucoisomerase, and phosphoglucomutase do not exhibit dramatic decreases in activity and appear to be in excess of starch accumulation rates. Starch accumulation is spatially localized in the inner and radial pericarp and columella, whereas the outer pericarp and seed locule contain little starch. The seed locule is characterized by lower activities of Suc synthase, UDP-Glc pyrophosphorylase, phosphoglucomutase, ADP-Glc pyrophosphorylase, and soluble and insoluble starch synthases. The outer pericarp exhibits comparatively lower activities of ADP-Glc pyrophosphorylase and insoluble starch synthase only. These data are discussed in terms of the developmental and tissue-specific coordinated control of Suc-to-starch metabolism.     

Seed coat development in Leucospermum cordifolium (Knight) Fourcade (Proteaceae) and a clarification of the seed covering structures in Proteaceae

MANNING, J. C. & BRITS, G. J., 1993. Seed coat development in Leucospermum cordifolium (Knight) Fourcade (Proteaceae) and a clarification of the seed covering structures in Proteaceae . The development of the seed coat and pericarp is studied in Leucospermum cordifolium from ovule to mature seed. The ovule and seed are characterized by a tegmic pachychalaza. The pericarp is adnate to the integuments from anthesis and remains unthickened to maturity. The outer integument forms the seed coat and the seed is endotestal: the outer epidermis becomes tanniniferous and the inner epidermis develops into a crystalliferous palisade. The inner integument degenerates at an early stage. Examination of the literature reveals that the crystal palisade layer of the outer integument has been erroneously assumed to constitute an endocarp. This finding indicates that a re-interpretation of all published information on the seed coat in indehiscent Proteaceae is necessary before any speculations on the phylogenetic significance of the seed coat can be entertained.     

Postprandial Changes of Free Amino Acids in the Rumen Fluid of Steers Fed with or without Monensin

The distribution and the relaxation times of water in tomato fruits were measured by ¹H-NMR imaging with a resolution of 0.2 × 0.2 mm² area and 1 mm thickness. Water with a long relaxation time was preferentially accumulated in seeds and seed envelopes in immature green fruit. The total amount of water increased in mature red fruit, where water with a long relaxation time was localized in outer walls of the pericarp and water with a shorter relaxation time was distributed throughout all tissues except for seeds and seed envelopes. ¹ H-NMR imaging apparently distinguished the physiological variations among different types of tissues and the physiological changes during maturation of tomato fruit.     

Kaffeinsynthese in Früchten und Gewebekulturen von Coffea arabica

Summary During fruit development the relative caffeine content of the pericarp falls from 1.68% to 0.24% on a dry weight basis, but remains more or less constant in the seed (about 1.25%). On an absolute basis, the pericarp has twice as much and the seed twenty times as much caffeine at maturity as at the beginning of fruit development. Tissue cultures of seed tissue (endosperm) produce caffeine and release it into the growth medium. Both pericarp and endosperm fed with NaH¹⁴CO₃ synthesize ring-labelled caffeine. Light strongly stimulates the methylation step of caffeine synthesis in the pericarp.

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Diese Arbeit wurde vom Schweizerischen Nationalfonds für wissenschaftliche Forschung unterstützt.