scholarly journals Understanding the cone scale in Cupressaceae: insights from seed-cone teratology in Glyptostrobus pensilis

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4948 ◽  
Author(s):  
Veit Martin Dörken ◽  
Paula J. Rudall
Keyword(s):  
Vascular Bundle ◽  
Central Position ◽  
Wild Type ◽  
Cone Axis ◽  
Seed Cone ◽  
Seed Scale ◽  
Short Shoots ◽  
Sterile Seed ◽  
Fertile Seed ◽  
Cone Scale

Both wild-type and teratological seed cones are described in the monoecious conifer Glyptostrobus pensilis and compared with those of other Cupressaceae sensu lato and other conifers. Some Cupressaceae apparently possess a proliferation of axillary structures in their cone scales. In our interpretation, in Glyptostrobus each bract of both typical and atypical seed cones bears two descending accessory shoots, interpreted here as seed scales (ovuliferous scales). The primary seed scale is fertile and forms the ovules, the second is sterile and forms characteristic tooth-like structures. The bract and the two axillary seed scales are each supplied with a single distinct vascular bundle that enters the cone axis as a separate strand; this vasculature also characterises the descending accessory short shoots in the vegetative parts of the crown. In wild-type seed cones, the fertile seed scale is reduced to its ovules, and the ovules are always axillary. In contrast, the ovules of some of the teratological seed cones examined were located at the centre of the cone scale. An additional tissue found on the upper surface of the sterile lower seed scale is here interpreted as the axis of the fertile seed scale. Thus, the central position of the ovules can be explained by recaulescent fusion of the upper fertile and lower sterile seed scales. In several teratological cone scales, the ovules were enveloped by an additional sterile tissue that is uniseriate and represents an epidermal outgrowth of the fertile seed scale. Close to the ovules, the epidermis was detached from lower tissue and surrounded the ovule completely, except at the micropyle. These teratological features are potentially significant in understanding seed-cone homologies among extant conifers.

Seed cone traits and insect damage in Tsuga canadensis (Pinaceae)

2004 ◽  
Vol 34 (1) ◽  
pp. 261-265 ◽  
Author(s):  
Jean J Turgeon ◽  
Chuck Jones ◽  
M Isabel Bellocq
Keyword(s):  
Seed Production ◽  
Tsuga Canadensis ◽  
Insect Damage ◽  
First Report ◽  
Seed Cone ◽  
Length Width ◽  
Maximum Proportion ◽  
Sterile Seed ◽  
The Impact ◽  
Filled Seeds

We measured seed cones of Tsuga canadensis (L.) Carrière, assessed seed potential (number of fertile scales × 2) and seed efficiency (number of filled seeds/seed potential), and estimated the impact of Eupithecia mutata Pearsall (Lepidoptera: Geometridae) and Megastigmus hoffmeyeri Walley (Hymenoptera: Torymidae) on seed production. Mean length, width, and volume of healthy cones varied little among sites from Ontario. Cones had about 28 scales; 13 were sterile. Seed potential and seed efficiency differed among sites, ranging from 25 to 31 ovules and 24% to 72%, respectively. The number of scales (both sterile and fertile) increased with cone volume, but the proportion of fertile scales was independent of cone size. The maximum proportion of cones infested by E. mutata was 21%. On average, each larva destroyed >90% of the filled seeds from each cone, thus from a practical perspective, the proportion of T. canadensis seeds destroyed per site was equivalent to the proportion of seed cones infested. The proportion of cones infested by M. hoffmeyeri ranged from 9% to 40%, but the proportion of seeds destroyed per site (range: 1.1%–6.1%) was much lower than that of E. mutata. The maximum number of M. hoffmeyeri-infested seeds per cone was seven. To our knowledge, this is the first report documenting cone traits of T. canadensis and the impact of E. mutata and M. hoffmeyeri.

Taxonomy and origin of present-day morphometric variation in Picea glauca (×engelmannii) seed-cone scales in North America

2006 ◽  
Vol 84 (7) ◽  
pp. 1129-1141 ◽  
Author(s):  
W.L Strong ◽  
L.V. Hills
Keyword(s):  
Rocky Mountains ◽  
Picea Glauca ◽  
White Spruce ◽  
Black Hills ◽  
Picea Engelmannii ◽  
Morphometric Variation ◽  
Engelmann Spruce ◽  
Seed Cone ◽  
Northern United States ◽  
Cone Scale

White spruce ( Picea glauca (Moench) Voss) and Engelmann spruce ( Picea engelmannii Parry ex Engelm.) seed-cones from 676 sites in Canada and the northern United States were analyzed to determine the degree and spatial extent of interspecific hybridization. Fifteen cone-scale variables were analyzed, with percent free-scale and scale shape considered best for differentiating these taxa. The results show that putative Engelmann spruce and their hybrids occur mostly in the vicinity of the Rocky Mountains. Putative white spruce occurs across Canada east of the Rocky Mountains, whereas white × Engelmann hybrids occur eastward to Manitoba and northward to 68° latitude in northwest Canada. To explain the occurrence of the latter taxon hundreds of kilometres from an Engelmann spruce pollen source, it is hypothesized that palaeohybridization occurred during the Wisconsinan glacial period, probably in the southern Montana – Wyoming – Black Hills (South Dakota) region, with the resulting hybrids spreading north and northeastward into interior Canada following the retreat of the Laurentide glacier. White and Engelmann spruce have morphologically distinct cone-scales, whereas their hybrids have intermediate characteristics. An emended species ( Picea albertiana ) and two subspecies (P. albertiana subsp. albertiana and P. albertiana subsp. ogilviei) are proposed to account for morphological intermediates between the parent species.

Seed cones of Metasequoia milleri from the Middle Eocene of southern British Columbia

1984 ◽  
Vol 62 (2) ◽  
pp. 281-289 ◽  
Author(s):  
James F. Basinger
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Close Association ◽  
Single Species ◽  
Metasequoia Glyptostroboides ◽  
Adaxial Surface ◽  
Close Resemblance ◽  
Cone Axis ◽  
Living Species ◽  
Cone Scale

Permineralized ovulate cones of Metasequoia milleri Rothwell and Basinger (Taxodiaceae) are preserved in silicified peats of the Middle Eocene Allenby Formation near Princeton, B.C., Canada. Cones are about 17 mm wide and 25 mm long and are borne terminally on sparsely leaved stalks or peduncles. Twenty to 30 cone scales are arranged decussately on the cone axis. Externally, cone scales are broadly hexagonal and labiate in appearance owing to a medial cleft. Several ovules, with micropyles directed toward the cone axis, are attached to the adaxial surface of the cone scale. Seeds are 3–4 mm wide and about 5 mm long, with two lateral wings each approximately equal in size to the central seed body. Anatomical similarity to and close association with pollen cones and vegetative remains of M. milleri indicate that all organs belong to a single species. The vegetative body and pollen cones of M. milleri differ in few respects from those of living Metasequoia glyptostroboides Hu and Cheng. The seed cones of M. milleri cannot be distinguished from those of the living species. The close resemblance of the two species indicates evolutionary near stasis, at least structurally, throughout the Tertiary.

scholarly journals Morphological Characterization and Transcriptome Analysis of New Dwarf and Narrow-Leaf (dnl2) Mutant in Maize

2022 ◽  
Vol 23 (2) ◽  
pp. 795
Author(s):  
Lulu Han ◽  
Chenggong Jiang ◽  
Wei Zhang ◽  
Hongwu Wang ◽  
Kun Li ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Growth ◽  
Plant Height ◽  
Vascular Bundle ◽  
Secondary Cell Wall ◽  
Leaf Shape ◽  
Wall Structure ◽  
Wild Type ◽  
Narrow Leaf ◽  
Leaf Phenotype

Lodging is the primary factor limiting high yield under a high plant density. However, an optimal plant height and leaf shape can effectively decrease the lodging risk. Here we studied an ethyl methanesulfonate (EMS)-induced dwarf and a narrow-leaf mutant, dnl2. Gene mapping indicated that the mutant was controlled by a gene located on chromosome nine. Phenotypic and cytological observations revealed that dnl2 showed inhibited cell growth, altered vascular bundle patterning, and disrupted secondary cell wall structure when compared with the wild-type, which could be the direct cause of the dwarf and narrow-leaf phenotype. The phytohormone levels, especially auxin and gibberellin, were significantly decreased in dnl2 compared to the wild-type plants. Transcriptome profiling of the internodes of the dnl2 mutant and wild-type revealed a large number of differentially expressed genes enriched in the cell wall biosynthesis, remodeling, and hormone biosynthesis and signaling pathways. Therefore, we suggest that crosstalk between hormones (the altered vascular bundle and secondary cell wall structure) may contribute to the dwarf and narrow-leaf phenotype by influencing cell growth. These results provide a foundation for DNL2 gene cloning and further elucidation of the molecular mechanism of the regulation of plant height and leaf shape in maize.

Regarding the structure and possible function of the columella in seed cones of Callitroideae (Cupressaceae): a morpho-anatomical approach

2017 ◽  
Vol 65 (5) ◽  
pp. 471 ◽  
Author(s):  
Veit Martin Dörken ◽  
Armin Jagel
Keyword(s):  
Chemical Defence ◽  
The Past ◽  
Cone Axis ◽  
Seed Cone ◽  
Resin Glands

‘Columella’-named structures in seed cones of callitroid Cupressaceae were investigated. In the past, the term columella was used for different structures, which should not be summarised and treated under the same name. We suggest that all apices should be called columella, which exclusively represent the prolonged tip of the cone axis and do not reach the periphery of the seed cone and do not take part in it. The three distal lobes in Fitzroya Lindl. represent a sterile, strongly reduced, distal whorl of cone scales and not naked nucelli or resin glands as suggested in former studies. They should not be termed columella. The columellae and also the three lobes in Fitzroya may play a role within the pollination process and possibly in the chemical defence against pathogens. The columella, as it is defined here, is not restricted to the Callitroideae and is also present in other Cupressaceae, including Cupressus L. and Thujopsis Siebold & Zucc.

Pityostrobus mcmurrayensis sp.nov., a permineralized pinaceous cone from the Cretaceous of Alberta

1981 ◽  
Vol 59 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Ruth A. Stockey
Keyword(s):  
Early Cretaceous ◽  
Vascular Tissue ◽  
Secondary Xylem ◽  
Resin Canal ◽  
Seed Structure ◽  
Thin Sections ◽  
Mcmurray Formation ◽  
Cone Axis ◽  
Resin Canals ◽  
Cone Scale

A new pinaceous species is described from the Early Cretaceous (Albian) McMurray Formation of Alberta. The cone is partially lignitic with permineralized ovules, 13 cm long × 4 cm wide, and occurs in a siliceous sandstone matrix. Thin sections were made after embedding with bioplastic and infiltration of cut faces with epoxy. Externally the helically arranged flattened cone scales resemble those of extant Picea. Scales bear two inverted, winged ovules containing shrunken nucellar and megagametophyte tissue. The cone axis is slender and contains small wedges of secondary xylem lacking resin canals. Vascularization of the cone–scale complex is similar to the non-Pinus species of the Pinaceae with bract and scale traces separate at their origins. One large abaxial resin canal, 1 mm in diameter, accompanies the traces out into the scale for 1 cm before branching. Two large bundles of sclerenchyma accompany the scale vascular tissue and may have served to open the cone at maturity. The bract, small and triangular in outline, has a terete trace and two lateral resin canals. Cone and seed structure are closely comparable to fossil pinaceous genera Pseudoaraucaria and Pityostrobus and the non-Pinus genera of the extant Pinaceae.

scholarly journals Serotiny in southern hemisphere conifers

2013 ◽  
Vol 61 (6) ◽  
pp. 486 ◽  
Author(s):  
P. G. Ladd ◽  
J. J. Midgley ◽  
A. P. Nield
Keyword(s):  
Southern Hemisphere ◽  
Fire Regime ◽  
Dry Weight ◽  
Simple Relationship ◽  
Morphometric Measurements ◽  
The Family ◽  
Selection Of Species ◽  
Sterile Seed ◽  
Fertile Seed ◽  
Selection Of

Serotiny is a widespread trait in angiosperms in the southern hemisphere; however, it is less common in conifers and has been little examined in the only two genera of southern conifers (Callitris and Widdringtonia) that have serotinous cones. There is variation across the family in the size of cones, the amount of seed contained and the time over which the cones stay closed on the plant. Cones from most of the species were collected in the field and various morphometric measurements made including cone wet and dry weight, the number of seeds contained and their likely viability. Cones from a selection of species with different cone sizes were heated to increasing temperatures, to investigate the ability of cones to protect the contained seeds from heat. In comparison to the flowering plants, serotiny has developed comparatively recently in southern conifers (in the last 10–20 million years). In Widdringtonia, serotiny is relatively weak, whereas in Callitris, it varies from strong to non-existent. Cone size and fertile-seed production across the two genera varies and the number of fertile seeds produced is positively related to the size of the cone. In some species, there are sterile seed-like bodies. These may have developed to confuse seed predators, so fertile seeds have a better chance of survival. Larger (heavier) cones are more effective in protecting the contained seeds from the heat of fires than are smaller ones. There is no simple relationship between the cone size and type of environment occupied by the species. In regions where fire is unlikely, predictable but mild or completely unpredictable, the species tend to be non-serotinous. In temperate regions where hot fires are likely to have been a selective agent, the species tend to be more strongly serotinous, although fire is not essential to open the cones. The community and environment in which a species has evolved is likely to have influenced the development of the degree of serotiny for each species and this may still be a variable property among populations of some species, depending on the fire regime of the area in which they grow.

Production and distribution of seed and pollen cones on Larixlaricina trees in young plantations

1991 ◽  
Vol 21 (4) ◽  
pp. 446-454 ◽  
Author(s):  
Kathleen J. Tosh ◽  
G. R. Powell
Keyword(s):  
Seed Cone ◽  
Production And Distribution ◽  
Long Shoots ◽  
Short Shoots ◽  
Pollen Cone

Numbers and distributions of seed and pollen cones were assessed on 90 Larixlaricina (Du Roi) K. Koch trees of 5, 6, and 7 years. Respectively, 27, 90, and 96% of the trees bore seed cones and 0, 62, and 96% bore pollen cones. Numbers of seed cones per tree averaged 9, 206, and 390 and of pollen cones, 0, 42, and 838. Ninety-nine, 88, and 30% of the seed cones were borne laterally on long shoots. At ages 6 and 7 years, 22 and 2% of the pollen cones were borne laterally. Seed cones occurred equally on side or lower surfaces of parent long shoots, but pollen cones were mainly on lower surfaces. Lateral cones were mainly borne proximally on the parent long shoots at first production; later, some were medial and a few were distal. Proportions of short shoots bearing seed cones increased acropetally. More short shoots bearing pollen cones were medial than proximal or distal. At age 6, proximal short shoots bearing pollen cones exceeded distal ones: the reverse occurred at age 7. Seed-cone and pollen-cone zones were not separate in the crowns, but within any shoot category, seed cones predominated on stronger shoots and pollen cones on weaker shoots.

Bud development in Larix occidentalis. II. Cone differentiation and early development

1979 ◽  
Vol 57 (14) ◽  
pp. 1557-1572 ◽  
Author(s):  
John N. Owens ◽  
Marje Molder
Keyword(s):  
Shoot Elongation ◽  
Larix Occidentalis ◽  
Short Shoot ◽  
Bud Development ◽  
Seed Cone ◽  
Long Shoots ◽  
Short Shoots ◽  
Old Trees ◽  
Mother Cells ◽  
Pollen Cone

The time and method of cone-bud differentiation and the phenology of cone-bud development were studied in 10- to 20-year-old trees growing outside their natural range and three 50-year-old trees growing within their natural range.Both pollen-cone and seed-cone buds of western larch (Larix occidentalis Nutt.) normally differentiated on short shoots that were at least 1 year old. Pollen-cone buds were commonly on proximal nonvigorous, often pendant vegetative long shoots in lower regions of the crown, whereas seed-cone buds were usually found on distal short shoots on vigorous but less pendant vegetative long shoots in upper regions of the crown.All potential cone buds were indistinguishable from potential vegetative short shoot buds during bud-scale initiation. In early June, when vegetative short shoots had begun to initiate leaves, cone-bud apices entered a period of differentiation during which time the mitotic frequency of the apices greatly increased followed by a marked increase in apical size. During differentiation, pollen-cone apices did not initiate any basal foliar organs and a short stalk resulted at the base of the cone, whereas seed-cone apices initiated a few basal foliar primordia before bract initiation began. Microsporophyll initiation began during the last half of June and initiation occurred rapidly until the end of July. Micros porangial development occurred from August to late October when fully developed pollen-cone buds became dormant. Pollen mother cells began meiosis before dormancy and overwintered at the diffuse stage. Bract initiation began about the end of June, was rapid until mid-August, then continued more slowly until seed-cone buds became dormant in late October. Ovuliferous scales were initiated acropetally from mid-August until dormancy. Cone-bud differentiation occurred at about the end of the period of vegetative lateral long shoot elongation at all locations.

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