The seed cone Eathiestrobus gen. nov.: Fossil evidence for a Jurassic origin of Pinaceae

? Premise of the study: Pinaceae and nonpinoid species are sister groups within the conifer clade as inferred from molecular systematic comparisons of living species and therefore should have comparable geological ages. However, the fossil record for the nonpinoid lineage of extant conifer families is Triassic, nearly 100 million years older than the oldest widely accepted Lower Cretaceous record for Pinaceae. An anatomically preserved fossil conifer seed cone described here extends the stratigraphic range of Pinaceae nearly 30 million years, thus reducing the apparent discrepancy between evidence from the fossil record and inferences from systematic studies of living species. ? Methods: Material was prepared as serial thin sections by the cellulose acetate peel technique, mounted on microscope slides, and viewed and photographed using transmitted light. ? Key results: A large cylindrical cone consisting of bract-scale complexes that diverge from the cone axis in a helical phyllotaxis has bracts and scales that separate from each other in the midregion and are of equal length and of nearly equal width. The cone has two inverted and winged seeds that are attached to the adaxial surface of each cone scale and, thus, represents an early member of the Pinaceae. ? Conclusions: Eathiestrobus mackenziei gen. et sp. nov. extends the fossil record for well-documented members of the family Pinaceae from the Lower Cretaceous to the Kimmeridgian Stage of the Upper Jurassic. This species also clarifies the set of characters that are diagnostic for seed cones of Pinaceae and reveals possible plesiomorphic characters for seed cones of the family.     

松科早期球果研究的历史和现状

本文主要对早白垩世到老第三纪渐新世这段时间的松科化石球果的研究作了系统回顾和总结。松科化石球果的研究经历了一个由分散、幼稚到系统、成熟的发展过程,现在将松科化石球果分为三个属：Pityostrobus、Pseudoaraucaria 及Pinus。其中Pseudoaraucaria及Pinus为两个自然属,Pseudoaraucaria已经绝灭。Pityostrobus作为一个器官属,包括那些在松科中分类位置不明的球果。对松科化石球果进行细致的外部形态及内部结构的研究主要目的在于演化关系的探讨上：对于Pinus,主要探讨这个属内各个亚属、组、亚组之间的演化关系;对于Pityostrobus和Pseudoaraucaria,通过绝灭类型的分析,探索松科内各个类群(包括绝灭的)的演化关系进而完成进化树是研究的主要方向,现在这方面已有了Pinus中心说及Pseudoaraucaria分支说两个假说。     

松科早期球果研究的历史与现状

本文主要对早白垩世到老第三纪渐新世这段时间的松科化石球果的研究作了系统回顾和总结。松科化石球果的研究经历了一个由分散、幼稚到系统、成熟的发展过程,现在将松科化石球果分为三个属：Ｐｉｔｙｏｓｔｒｏｂｕｓ、Ｐｓｅｕｄｏａｒａｕｃａｒｉａ及Ｐｉｎｕｓ。其中Ｐｓｅｕｄｏａｒａｕｃａｒｉａ及Ｐｉｎｕｓ为两个自然属,Ｐｓｅｕｄｏａｒａｕｃａｒｉａ已经绝灭。Ｐｉｔｙｏｓｔｒｏｂｕｓ作为一个器官属,包括那些在松科中分类位置不明的球果。对松科化石球果进行细致的外部形态及内部结构的研究主要目的在于演化关系的探讨上：对于Ｐｉｎｕｓ,主要探讨这个属内各个亚属、组、亚组之间的演化关系;对于Ｐｉｔｙｏｓｔｒｏｂｕｓ和Ｐｓｅｕｄｏａｒａｕｃａｒｉａ,通过绝灭类型的分析,探索松科内各个类群（包括绝灭的）的演化关系进而完成进化树是研究的主要方向,现在这方面已有了Ｐｉｎｕｓ中心说及Ｐｓｅｕｄｏａｒａｕｃａｒｉａ分支说两个假说。     

Seed cone anatomy of Cheirolepidiaceae (Coniferales): Reinterpreting Pararaucaria patagonica Wieland

? Premise of the study: Seed cone morphology and anatomy reflect some of the most important changes in the phylogeny and evolutionary biology of conifers. Reexamination of the enigmatic Jurassic seed cone Pararaucaria patagonica reveals previously unknown systematically informative characters that demonstrate affinities with the Cheirolepidiaceae. This paper documents, for the first time, internal anatomy for seed cones of this important extinct Mesozoic conifer family, which may represent the ghost lineage leading to modern Pinaceae. ? Methods: Morphology and anatomy of cones from the Jurassic La Matilde Formation in Patagonia are described from a combination of polished wafers and thin section preparations. New photographic techniques are employed to reveal histological details of thin sections in which organic cell wall remains are not preserved. Specific terminology for conifer seed cones is proposed to help clarify hypotheses of homology for the various structures of the cones. ? Key results: Specimens are demonstrated to have trilobed ovuliferous scale tips along with a seed enclosing pocket of ovuliferous scale tissue. Originally thought to represent a seed wing in P. patagonica, this pocket-forming tissue is comparable to the flap of tissue covering seeds of compressed cheirolepidiaceous cones and is probably the most diagnostic character for seed cones of the family. ? Conclusions: Pararaucaria patagonica is assigned to Cheirolepidiaceae, documenting anatomical features for seed cones of the family and providing evidence for the antiquity of pinoid conifers leading to the origin of Pinaceae. A list of key morphological and anatomical characters for seed cones of Cheirolepidiaceae is developed to facilitate assignment of a much broader range of fossil remains to the family. This confirms the presence of Cheirolepidiaceae in the Jurassic of the Southern Hemisphere, which was previously suspected from palynological records.     

濒危植物梵净山冷杉的球果与种子性状研究北大核心CSCD

梵净山冷杉(Abies fanjingshanensis)为国家一级保护濒危植物。为了揭示梵净山冷杉球果发育和成熟过程的性状特征,以确定成熟球果的适宜采种期。该研究对梵净山冷杉自然生长区内成年结实母树的球果进行跟踪观测和定期采集,通过物理解剖和形态学参数测定,比较分析不同采种期梵净山冷杉的球果、种鳞和种子的性状差异。结果显示:(1)梵净山冷杉的球果每年7月中旬开始形成,10月中旬开始成熟,发育早期至发育后期球果的长度和宽度显著增加,发育后期至成熟期形态和颜色均无明显变化。(2)成熟球果平均长、宽、鲜重、干重和相对含水量分别为7.18 cm、3.84 cm、36.98 g、20.33 g和45.06%。(3)成熟球果的平均种鳞层数为30.76层,种鳞总数为250.67片,平均出种量436.67粒,平均种子饱满率82.49%。(4)成熟球果基部、中部、上部的种子性状不同,且球果中部的种子性状参数最大,饱满率最高,种子平均长、宽、厚分别为9.14、2.30、2.37 mm,千粒重11.44 g。研究表明,梵净山冷杉的球果从形成至成熟过程约3个月,成熟球果的最佳采种时间为10月下旬,发育后期和成熟球果的形态和颜色差异不明显,不能以颜色和形态作为球果成熟的判定依据;种鳞与球果的发育和成熟同步,球果中部的种鳞能够完全发育,且形状参数最大,孕育的种子最饱满;梵净山冷杉成熟球果出种量大、饱满率高,但是种子小、重量轻。     

Structure and affinities of the petrified plants from the cretaceous of Northern Japan and Saghalien. XII.Obirastrobus gen. nov., petrified pinaceous cones from the Upper Cretaceous of Hokkaido

Two new species of pinaceous cones belonging toObirastrobus gen. nov. are described from the Upper Cretaceous of Hokkaido. Bract-scale complexes are arranged helically and each consists of a small bract and a large scale. The bract and scale are separated. The scale tapers distally and its apex does not become papery. The anatomy of the bracts, scales, and seeds shows a combination of features unique in the Pinaceae and resembling those of the extant genusKeteleeria and the extinct genusPseudoaraucaria. Consecutive number from the previous paper (Ohsawaet al., 1992). Supported by Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture Nos. 63540545 and 02640533 to Makoto Nishida.     

AGAMOUS subfamily MADS-box genes and the evolution of seed cone morphology in Cupressaceae and Taxodiaceae

In this comparative developmental genetics study, we test hypotheses based on fossil and morphological data on reproductive organ morphology and evolution in conifers--specifically, the ovule-bearing organ in Cupressaceae and Taxodiaceae. Genes homologous to the Arabidopsis gene AGAMOUS are expressed in ovuliferous scales of spruces (Picea) throughout development. Previous studies have shown that the AGAMOUS subfamily of MADS-box genes predates the split between angiosperms and gymnosperms, and that these genes have in part conserved functions in reproductive development among seed plants, especially in the specification of identity of the ovule-bearing organs. These data indicate that their expression in conifer families other than Pinaceae might be used as markers for organs homologous to the Pinaceae ovuliferous scale. Here we have isolated putative AGAMOUS orthologs from Cupressaceae and Taxodiaceae and analyzed their expression pattern in seed cones to test for the presence of morphological homologs of ovuliferous scales. Our results were not congruent with the hypothesis that the tooth of the Cryptomeria seed cone is homologous to the Picea ovuliferous scale. Likewise, the hypothesis that the bracts of Thujopsis and Juniperus contain fused ovuliferous scales was not supported. However, we found expression of AGAMOUS homologs in the sterile bracts of Cupressaceae seed cones at late developmental stages. This expression probably represents a novel gene function in these conifer families, since no corresponding expression has been identified in Pinaceae. Our study suggests that the evolutionary history of modern conifer cones is more diverse than previously thought.     

Measuring the impact of Leptoglossus occidentalis (Heteroptera: Coreidae) on seed production in lodgepole pine using an antibody-based assay

We measured the impact of Leptoglossus occidentalis on seed production in lodgepole pine, Pinus contorta variety latifolia Engelmann, using an antibody marker developed to detect residual saliva in fed-on seeds. Nymphs, adult females, and adult males were caged on cones during early, mid- and late season cone development. Individual analysis of 12,887 seeds extracted from 365 cones revealed that 37.3% seeds tested positive for seed bug saliva. The antibody assay was 38 times more effective than radiography at detecting seed bug damage. Radiography can detect partially emptied seed but cannot discriminate between aborted seeds and those emptied by seed bugs. The antibody marker was least sensitive in detecting early season damage compared with mid- and late season damage. We hypothesize that residual saliva in seeds fed on early in the season was either absorbed by the damaged seed or degraded over time. Early season feeding resulted in the greatest number of seeds fused to cone scales and the extraction efficiency for cones exposed to feeding during this time was reduced by 64% compared with control cones. Adding fused seeds to antibody-positive seeds raised the proportion of damaged seeds to 48.3%. At all stages of cone development, adult females were the most destructive life stage, damaging up to two seeds per day late in the season. When seed losses were adjusted to damage per degree-day, female damage was greatest early in the season, while males caused the same amount of damage regardless of cone development period. The results of the antibody assay provide baseline data for developing damage prediction formulae, and establish L. occidentalis as a potentially serious pest in lodgepole pine seed orchards.     

不同区域典型树木的空间分布格局及关联性

以温带长白山(CBS)、暖温带关帝山(GDS)、亚热带黑石顶(HSD)样地监测数据为基础,采用成对相关函数g(r)分析了3个样地共有的3科(松科、壳斗科、蔷薇科)树木的空间分布格局及其关联性.结果表明:不同样地3科树木分布数量及结构特征存在差异.松科在GDS分布数量较多,呈双峰型径级结构,在CBS和HSD分布数量少,径级结构近似正态分布;壳斗科在CBS和GDS分布数量少,分别呈双峰型和偏正态径级结构,在HSD分布数量多,呈倒"J"型径级分布;蔷薇科在GDS分布数量多,呈"L"型径级分布,在CBS和HSD分布相对较少,径级结构分别呈倒"J"型和"L"型分布.3科树木空间分布格局在不同样地表现也不同,松科的大径级个体在CBS和GDS小尺度上呈均匀分布,在HSD呈聚集分布,中、小径级在3个样地均呈聚集分布;壳斗科在CBS以大径级个体为主,呈近似随机分布,在GDS和HSD以中、小径级为主,呈聚集性分布格局;蔷薇科在3个样地均为聚集分布.3科树木的聚集程度均随尺度增加而降低.大径级的壳斗科个体在CBS和HSD与松科呈不相关或小尺度负相关关系,中、小径级的壳斗科在CBS和GDS与松科呈负相关关系,但在HSD与松科表现为正相关;松科与蔷薇科在3个样地均表现为负相关;中、小径级的壳斗科与蔷薇科在CBS和GDS呈正相关关系,但在HSD呈负相关关系.总之,3科树木空间分布格局及关联性随径级、尺度而变化且在不同样地内有不同表现.     

Morphological "primary homology" and expression of AG-subfamily MADS-box genes in pines, podocarps, and yews

The morphological variation among reproductive organs of extant gymnosperms is remarkable, especially among conifers. Several hypotheses concerning morphological homology between various conifer reproductive organs have been put forward, in particular in relation to the pine ovuliferous scale. Here, we use the expression patterns of orthologs of the ABC-model MADS-box gene AGAMOUS (AG) for testing morphological homology hypotheses related to organs of the conifer female cone. To this end, we first developed a tailored 3'RACE procedure that allows reliable amplification of partial sequences highly similar to gymnosperm-derived members of the AG-subfamily of MADS-box genes. Expression patterns of two novel conifer AG orthologs cloned with this procedure-namely PodAG and TgAG, obtained from the podocarp Podocarpus reichei and the yew Taxus globosa, respectively-are then further characterized in the morphologically divergent female cones of these species. The expression patterns of PodAG and TgAG are compared with those of DAL2, a previously discovered Picea abies (Pinaceae) AG ortholog. By treating the expression patterns of DAL2, PodAG, and TgAG as character states mapped onto currently accepted cladogram topologies, we suggest that the epimatium-that is, the podocarp female cone organ previously postulated as a "modified" ovuliferous scale-and the canonical Pinaceae ovuliferous scale can be legitimally conceptualized as "primary homologs." Character state mapping for TgAG suggests in turn that the aril of Taxaceae should be considered as a different type of organ. This work demonstrates how the interaction between developmental-genetic data and formal cladistic theory could fruitfully contribute to gymnosperm systematics.     

Foraging ecology of the South Australian glossy black‐cockatoo (Calyptorhynchus lathami halmaturinus)

The endangered South Australian glossy black‐cockatoo (Calyptorhynchus lathami halmaturinus Mathews 1912) feeds almost exclusively on the seeds of the drooping sheoak (Allocasuarina verticillata), and shows marked preferences for individual trees. This field study investigated foraging ecology and tree selection through observations of foraging birds and measurements of trees and seed cones. The cockatoos spent the vast majority of their foraging time (94%) handling seed cones, and handling behaviour was highly stereotyped. Handling time per cone was correlated primarily with cone size, while seed intake rate was correlated primarily with seed mass per cone. The cockatoos fed mostly in trees with signs of previous feeding. They tended initially to sample trees with large seeds, and to stay for long feeding bouts in trees with high ratios of seed‐to‐cone mass. As a result of these biases, feeding was concentrated in trees with high seed mass per cone. Preferred trees were also larger, with higher ratios of seed‐to‐cone mass and larger seeds containing more lipid and protein. By feeding from selected trees the cockatoos increased both their seed intake rate and the nutritional quality of the seeds ingested, thereby increasing their energy intake rate by an estimated 28%. They did not discriminate against trees that had re‐grown from basal shoots after fires. Insect larvae were present in some seed cones but the cockatoos did not appear to actively seek them. Males foraged 19% more efficiently than females, resulting in greater daily food intake. The characteristics of individual A. verticillata trees that determined the cockatoos’ feeding rates were also correlated with their distribution on a regional scale. This suggests that the distribution of this endangered cockatoo depends not only on the presence of food trees, but also on their regionally varying feeding profitability.     

REPRODUCTIVE BIOLOGY OF THE CERRO CUADRADO (JURASSIC) FOSSIL CONIFERS: PARARAUCARIA PATAGONICA

Seventy-two silicified cone specimens of Pararaucaria patagonica Wieland from the Cerro Cuadrado (Jurassic) petrified forest in Patagonia were studied by use of thin sections and reflected light. Traces from the cone axis stele to the bract and ovuliferous scale are separate at their origins. In cross section the abaxially concave ovuliferous scale trace and massive circular bract trace branch half-way out into the cone-scale complex. Two triangular-shaped bundles of fibers follow the scale trace into the laminar part of the ovuliferous scale. Both surfaces of the ovuliferous scale possess hairs which may have assisted in cone closure. Cones typically contain one flattened, winged seed per ovuliferous scale. Multi-layered seed integuments are represented by an inner fleshy layer of large cells filled with a black amorphous material, a sclerotesta consisting of wedges or fan-shaped groups of sclereids oriented at right angles to the seed surface, and a thin, often crushed fleshy layer. Seed wings consist of anastomosing, branched cells resembling glandular hairs and containing many intercellular spaces. Well-preserved polycotyledonous embryos containing up to eight cotyledons are present in several cones. Tissues of the embryo including the shoot apex, calyptroperiblem, hypocotyl, and cotyledons are described. On the basis of anatomical and morphological features, specimens of P. patagonica are compared to members of both extant and extinct families of conifers including the Araucariaceae, Taxodiaceae, Pinaceae, Cupressaceae, and Cheirolepidaceae.     

A NEW TAXODIACEOUS SEED CONE FROM THE OLIGOCENE OF WASHINGTON

Cunninghamiostrobus goedertii is described as a new species based on permineralized seed cones from the Early Oligocene of Washington. The fossils come from the Makah Formation and were found on the northern shore of the Olympic Peninsula. The cone consists of numerous bract-scale complexes arranged helically around a central axis. Each bract-scale complex has a large bract bearing a small flap of tissue adaxially that represents the ovuliferous scale. Up to three seeds were produced on each complex. The vascular trace to the bract-scale complex diverges from the vascular cylinder of the cone axis as a concentric strand. This divides in the outer cortex of the axis to form a large collateral bract tract abaxially and a minute scale trace adaxially. The latter continues outward to supply the ovuliferous scale. The bract trace divides, forming many strands outward which occur in a row with transfusion tissue between them. Many resin canals also occur in the bract. The new cone combines features found in modern cones of Athrolaxis, Cunninghamia, and Taiwania but is most similar to Cunninghamiostrobus yubariensis from the Late Cretaceous of Japan.     

Seed dispersal of the Korean pine,Pinus koraiensis,by the red squirrel,Sciurus vulgaris

Seed hoarding behavior of the red squirrel,Sciurus vulgaris, was studied in relation to the amount of dispersed seeds of the Korean pine,Pinus koraiensis, and the distribution of its seedlings. After removing a cone from a tree, squirrels sat on the ground and ripped off its cone scales before transporting it. A mean of 3.2 seeds were scatter-hoarded per hole. Of 7.7×10⁴ mature seeds produced in a 0.21 ha planted Korean pine forest, 22% were estimated to be directly eaten by four squirrels, 9% were hoarded by them in the pine forest and 65% were cached outside the forest. Squirrels rediscovered hoarded seeds frequently, until the ground was covered with snow, during the period from snow fall until seed germination the next spring, few hoarded seeds were utilized. Korean pine seedlings were found up to 600 m from their mother trees. Scatter-hoarding by squirrels extensively contributes to seed dispersal to places suitable for the regeneration of the Korean pine. The large size of the cone, the absciss-layer at the cone penduncle, the infrequent dehiscence of cone scales, the large and wingless seeds, and the thick seed-coats have probably all been specialized to facilitate utilization by GenusSciurus.     

Cones structure and seed traits of four species of large‐seeded pines: Adaptation to animal‐mediated dispersal

Seed dispersal selection pressures may cause morphological differences in cone structure and seed traits of large‐seeded pine trees. We investigated the cone, seed, and scale traits of four species of animal‐dispersed pine trees to explore the adaptations of morphological structures to different dispersers. The four focal pines analyzed in this study were Chinese white pine (Pinus armandi), Korean pine (P. koraiensis), Siberian dwarf pine (P. pumila), and Dabieshan white pine (P. dabeshanensis). There are significant differences in the traits of the cones and seeds of these four animal‐dispersed pines. The scales of Korean pine and Siberian dwarf pine are somewhat opened after cone maturity, the seeds are closely combined with scales, and the seed coat and scales are thick. The cones of Chinese white pine and Dabieshan white pine are open after ripening, the seeds fall easily from the cones, and the seed coat and seed scales are relatively thin. The results showed that the cone structure of Chinese white pine is similar to that of Dabieshan white pine, whereas Korean pine and Siberian dwarf pine are significantly different from the other two pines and vary significantly from each other. This suggests that species with similar seed dispersal strategies exhibit similar morphological adaptions. Accordingly, we predicted three possible seed dispersal paradigms for animal‐dispersed pines: the first, as represented by Chinese white pine and Dabieshan white pine, relies upon small forest rodents for seed dispersal; the second, represented by Korean pine, relies primarily on birds and squirrels to disperse the seeds; and the third, represented by Siberian dwarf pine, relies primarily on birds for seed dispersal. Our study highlights the significance of animal seed dispersal in shaping cone morphology, and our predictions provide a theoretical framework for research investigating the coevolution of large‐seeded pines and their seed dispersers.     

Variation in seed packaging of a fleshy‐fruited conifer provides insights into the ecology and evolution of multi‐seeded fruits

• The study of intraspecific seed packaging (i.e. seed size/number strategy) variation across different populations may allow better understanding of the ecological forces that drive seed evolution in plants. Juniperus thurifera (Cupressaceae) provides a good model to study this due to the existence of two subspecies differentiated by phenotypic traits, such as seed size and cone seediness (number of seeds inside a cone), across its range.
• The aim of this study was to analyse seed packaging (seed mass and cone seediness) variation at different scales (subspecies, populations and individuals) and the relationship between cone and seed traits in European and African J. thurifera populations.
• After opening more than 5300 cones and measuring 3600 seeds, we found that seed packaging traits followed different patterns of variation. Large‐scale effects (region and population) significantly contributed to cone seediness variance, while most of the seed mass variance occurred within individuals. Seed packaging differed between the two sides of the Mediterranean Sea, with African cones bearing fewer but larger seeds than the European ones. However, no differences in seed mass were found between populations when taking into account cone seediness. Larger cones contained more pulp and seeds and displayed a larger variation in individual seed mass.
• We validated previous reports on the intraspecific differences in J. thurifera seed packaging, although both subspecies followed the same seed size/number trade‐off. The higher seediness and variation in seed mass found in larger cones reveals that the positive relationship between seed and cone sizes may not be straightforward.We hypothesise that the large variation of seed size found within cones and individuals in J. thurifera, but also in other fleshy‐fruited species, could represent a bet‐hedging strategy for dispersal.

     

The phylogenetic positions of the conifer genera Amentotaxus,Phyllocladus, and Nageia inferred from 18s rRNA sequences

To determine the evolutionary positions of the conifer genera Amentotaxus, Phyllocladus, and Nageia, we obtained 18S rRNA sequences from 11 new taxa representing the major living orders and families of gymnosperms. With the published Chlamydomonas as an outgroup, phylogenetic analyses of our new data and available sequences indicate that (1) the Gnetales form a monophyletic group, which is an outgroup to the conifers, (2) the conifers are monophyletic, (3) Taxaceae, Cephalotaxaceae, Cupressaceae, and Taxodiaceae form a monophyletic group, (4) Amentotaxus is closer to Torreya than to Cephalotaxus, suggesting that Amentotaxus is better to be classified as a member of Taxaceae, (5) Phyllocladus, Dacrycarpus, Podocarpus, and Nageia form a monophyletic group, and (6) Pinaceae is an outgroup to the other families of conifers. Our finding that Phyllocladus is a sister group of the Podocarpaceae disagrees with the suggestion that the phylloclade of the genus is an ancient structure and that the genus is a terminal taxon within the Podocarpaceae. The genus Nageia is more closely related to Podocarpus than to Dacrycarpus and was derived from within the Podocarpaceae. In conclusion, our data indicate that in conifers, the uniovulate cone occurred independently in Taxacaeae and Cephalotaxaceae, and in Podocarpaceae after the three families separated from Pinaceae, and support the hypothesis that the uniovulate cone is derived from reduction of a multiovulate cone.Correspondence to: S.-M. Chaw