ABSTRACT Tyloses are protoplasmic swellings of parenchyma cells into the lumen of adjacent conducting cells. They develop as part of the heartwood formation process, or in response to embolism or pathogen infection. Here, we report the oldest fossil evidence to date of tylosis formation that occurs in permineralized wood of the (pro)gymnosperm Dameria hueberi from the Tournaisian (lower Mississippian, ca. 350 Ma) of Australia. Different developmental stages of tylosis formation are recognizable that range from small bubble-like protrusions to dense tyloses entirely filling the lumen of the conducting cells. The trigger for the development of tyloses in D. hueberi remains unknown. A survey of the fossil record of tyloses shows their occurrence in most groups of vascular plants since the Carboniferous. Future research in this field will screen even older (Devonian) fossils for evidence of tyloses and aim to understand the roles these structures have had in plant–pathogen interactions and plant hydraulic properties in the past.

ABSTRACT An unknown species of Psammothidium (Achnanthidiaceae) was found in core sediment (~4000 cal yr BP) collected from Xingu ria, located in eastern Amazon Basin (Brazilian Amazon). The detailed morphology of the new species was examined and described using light (LM) and scanning electron (SEM) microscopy. The new species described here is mainly characterized by small valve dimensions, an irregular and expanded central area in rapheless valve (RLV) clearly visible in LM. Under SEM observations, the new species show slightly radiate striae with rectangular to rounded areolae present both on the surface and the valve mantle. Morphology and ecology of the new species is compared to those already described for the genus. Moreover, information about core chronology and the co-occurrence of other diatom species in the sample are also provided.

ABSTRACT Upper Triassic deposits of the Leigh Creek Coal Measures in South Australia yield exquisitely preserved plant fossils of a typical mid- to high-latitude Gondwanan flora. Here, we present a detailed cuticular analysis of the ginkgoalean leaf Sphenobaiera insecta J.M. Anderson et H.M. Anderson nov. emend., which is characterized by an unlobed or once-lobed, elliptic to oblanceolate lamina, abundant round to fusiform resin bodies, and absence of interveinal striae. We also propose an emendation to the genus diagnosis so that Sphenobaiera encompasses also unlobed leaves such as most of those attributed to S. insecta. Such leaves may be distinguished from morphologically similar co-occurring leaf taxa, such as Heidiphyllum elongatum (Pinales) and Rochipteris spp. (Petriellales), based on the characteristic resin bodies and sporadic occurrence of vein dichotomies in the central lamina. Sphenobaiera insecta leaves show common evidence of a particular type of herbivory damage along the leaf margin in the form of small (1–1.5-mm-long) semi-circular patches each lined by a crescent-shaped, darkened reaction rim.

ABSTRACT Several anthropogenic activities can impact forest carbon (C) dynamics. In the Himalaya, insufficient studies are available on the intensity and impacts of multiple anthropogenic activities on forest C stocks. Here, we studied the changes in tree C stock in temperate forest stands of Kashmir Himalaya due to anthropogenic disturbances. We sampled forest sites with High-Disturbance (HD) and Low-Disturbance (LD) by randomly generating points in Arc GIS 10.1. A total of 24 square plots (0.1 ha size), comprising 12 in each disturbance level, were laid for the estimation of tree C stock. The tree cutting and the mean basal area of cut stems per hectare was greater in HD sites as compared to LD sites. The rapid rate of tree cutting was indicated by a low stem/stump ratio of 1.7 on HD sites. At LD sites, the live trees contributed more to the C stock (94%) than in HD sites (80%). The intensity of tree cutting was far higher near human settlements, contributing with 28.9 Mgha−1 of carbon loss at the HD sites. Our results reveal that the cumulative impacts of anthropogenic disturbances, especially near human settlements where road connectivity and ease of access lead to faster logging, may change the forest structure and C stock potential in the temperate forests of Kashmir Himalaya. Our findings have direct implications for the climate-smart forestry and forest restoration in the region.

ABSTRACT New Caledonia is known for the diversity of its geological substrates, which have shaped its highly original and diverse flora. Here, the effect of the soil on the vegetation is described for several contact zones between ultramafic and other substrates. The main vegetation formations on soils derived from ultramafic rocks are described: low and medium altitude rainforests, high altitude rainforests, and maquis. The main types of maquis and the biological characteristics of maquis species are also presented.

ABSTRACT Cytomixis is a process of intercellular nuclear migration (INM) often observable in plant male meiosis. The genes responsible for this phenomenon have not been discovered yet. In an attempt to identify a “cytomictic chromosome,” we studied the male meiosis of wheat–rye single-chromosome substitution lines. Markers of the chromatin state were analyzed to figure out the nature of INM in cereal plants: is it a rather normal process or a consequence of random injury/deviation? There were no obvious correlations between the loss of wheat chromosome 1A, 2D, 5A, or 5D by hybrid plants and the frequency and cytological picture of INM in their meiosis. Acquisition of rye chromosome 1 Rv, 2 R, or 5 R did not correlate with any changes in the manifestation of INM either. Some unusual cytological patterns of the substituted-chromosome behavior were observed during INM. Chromosomes 1Rv, 2 R, and 5 R, which are alien to the wheat genome, were found to migrate preferentially between meiocytes. Analysis of post-translational histone modifications and synaptonemal-complex formation revealed that the migrating chromatin does not differ from the intact one. It is not inactivated, is properly condensed, and forms bivalents. Our findings suggest that none of the studied chromosomes carry “cytomictic genes.” At the same time, INM in male meiosis of cereals appears to be a normal process that may be involved in hybrid-genome rearrangements.

ABSTRACT Central to the agroecological transition is biodiversity, which, once restored in agroecosystems, should provide multiple ecosystem services that result from the interactions between different organisms. However, the diversity of expected services raises questions about the capacity of agroecosystems to simultaneously provide many of them as well as the possible existence of synergies and antagonisms. In particular, the relationships between crop-associated biodiversity (i.e. biodiversity in action in crops) and spontaneous biodiversity (i.e. biodiversity not directly related to agriculture) remain unclear. In this article, we analyse the impact of hedgerows on the preservation of spontaneous biodiversity, on the promotion of biotic regulation services such as pollination and pest control in agriculture, and on the interactions between spontaneous and associated biodiversity. Our analysis of the scientific literature shows that hedgerows are unique assets for the preservation of spontaneous biodiversity, while they also provide biotic regulation services to adjacent crops but only under specific conditions, which need to be better understood. We propose a functional conceptual framework of the ecological effects of hedgerows on associated biodiversity and we highlight the possible synergistic and antagonistic effects related to hedgerow characteristics and the life-history traits of the organisms under consideration. Our analysis therefore seeks to overcome the cleavage between associated biodiversity and spontaneous biodiversity. This approach is in keeping with a more harmonious relationship between agriculture and biodiversity.

ABSTRACT Thespesia populnea (L) Sol. ex Corrêa (Malvaceae), known as the Indian tulip tree, is a well-known fast-growing, economically and ecologically important evergreen species in the tropical forests of India. However, no reliable fossil evidence of Thespesia has been reported from the Cenozoic sediments of India so far. Here, we document for the first time a well-preserved leaf impression similar to extant leaves of Indian tulip tree from the latest Neogene (Pliocene: Rajdanda Formation) sediments of Chotanagpur Plateau, eastern India. The leaf specimen has a broadly ovate mesophyllous blade, with a conspicuous acuminate apex (drip-tip), a cordate base, a stout petiole, actinodromous primary veins and brochiododromous secondary veins. We recognise the new fossil species Thespesia neopopulnea Hazra, Mahato and Khan sp. nov. The recovery of this species and other earlier-described evergreen taxa from the same formation, suggests the existence of tropical, warm and humid climatic conditions during the depositional period.

ABSTRACT A Chara exhibiting extreme morphological features including stipulodes, spine cells, and bracteoles is described and subjected to barcoding procedures to determine whether it belongs to the Chara contraria group or the C. hispida group. MatK barcoding clearly placed it in the C. contraria clade which was consistent with gametangial morphology, but not stipulode, spine cell and bracteole morphology. The specimen was determined to be included in the Chara contraria var. hispidula taxon, not previously reported or described for Newfoundland, Canada, or the USA.

ABSTRACT Aflatunia ulmifolia (Franch.) Vassilcz. is a rare, poorly studied species from the Rosaceae Juss family. Its natural distribution range is limited to Central Asia (Western Tien Shan, Pamir-Alay, Dzhungarskiy and Kirghiz Alatau). Information on the current state of natural plant communities with the participation of A. ulmifolia, the introduction potential, and the methods of conservation of the species is limited. The aim of our study was to improve information about A. ulmifolia, by verifying its current distribution range, both in natural habitats and in places where it is introduced, and analyze the major ecological, morphological and biological characteristics of the species. We produced the most up-to-date species distribution map showing both natural and introduced populations of A. ulmifolia. For the first time, we provide a comprehensive list of tree and shrub species co-occurring with A. ulmifolia in Tajikistan, Kyrgyzstan, and Kazakhstan. We present detailed information on the successful introduction of A. ulmifolia in nine European and Asian countries. Although the species is not of immediate conservation concern, it might become vulnerable to extinction if its distribution range continues to shrink because of anthropogenic impact and natural disturbances. We argue for the development of effective conservation strategies for A. ulmifolia in nature and for the creation of stable introduction populations of this species in botanical gardens and arboretums.