Estudio histológico de la floración del manzano

89 p.Estudio histológico de la floración del manzan

Aproximación a la histología foliar de Bryonia, Malva, Plantago, Rubus, Taraxacum

El presente trabajo ofrece una aproximación a la morfología foliar de Bryonia dioica Rubus ulmifolius Malva sylvestris Plantago lanceolata y Taraxacum officinal

Histological/Biochemical composition of papyri

[EN] Papyrus, as a medium for writing, was made from the stems of the plant Cyperus papyrus (Basile, 1977; Wallert, 1989). Although it is unclear how papyri were produced, it is known that only the peeled stems were used in their manufacture (Basile, 1977; Franceschi et al., 2004). Non-destructive physical analysis of the surface of papyri commonly returns different results from one area of a sheet to another. The present work examines C. papyrus stems and papyri by optical and scanning electron microscopy (SEM) in order to determine their histological structure and gain insight into their gross biochemical compositionSIThis work was funded by the Spanish Ministerio de Economía y Competitividad through the projects La memoria escrita: estudio integral de los fondos papirológicos nacionales (MINECO.FFI2012- 39567-C02-01) and La memoria escrita: texto, materialidad y contexto de las colecciones papiraceas españolas (MINECO-FFI2015-65511-C2-1-P

Histological changes induced by the cynipid wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae) in leaves of the chestnut Castanea sativa (Fagaceae): Mechanisms of galling impact on host vigor

[EN] Dryocosmus kuriphilus (Hymenoptera: Cynipidae), the Asian chestnut gall wasp (ACGW), is an invasive pest that threatens native stands and orchards of European Sweet Chestnut (Castanea sativa Mill.). ACGW induces galls in stems, petioles, and midribs. These galls cause inhibition of tree growth and fruit production. An understanding of morphogenetic changes in host organs is important to evaluate how plant resources are redirected to galls. Structural divergences in C. sativa petioles, midribs, and respective galls were investigated. Larvae of D. kuriphilus are found in the central region of young petioles and midribs in the spring. They are positioned in the pith region of petioles and midribs, surrounded by vascular tissues. The increase in cell layers and volume is evident in the ground tissues of galls, i.e., parenchyma, collenchyma, and sclerenchyma that originate from ground meristem. Gall formation causes the separation of the original vascular system into several collateral and amphicribral vascular bundles. The vascular web branching likely favors the redirection of resources from developing leaf blades to the galls by compensatory hydraulic mechanisms. The rapid growth rates of galls are likely supported by an increased water supply to gall sites. Cytoplasmically dense and metabolically active nutritive linings of the larval chambers are the sole source of food for larvae. Nutritive cells are maintained by a rich vascular supply. The redifferentiation of mechanical tissue surrounding the nutritive tissue also requires energy and protects the D. kuriphilus larva until pupation. These vascular alterations impact the normal formation of tissues in distal regions of the leaf, which reduces the productivity of chestnut treesS

Tomato Graft Union Failure Is Associated with Alterations in Tissue Development and the Onset of Cell Wall Defense Responses

This article belongs to the Special Issue Advances in Cell Wall Research of Crop Plants[EN] Grafting is a technique applied to a considerable number of crops, with tomato standing out. However, this technique is limited by the obtaining of unfunctional grafts, which decrease the success rate and therefore the benefits achieved. The aim of this work was to analyze the failure in intraspecific grafting of tomato plants, focusing on tissue development, cell wall defense reactions, and the distribution of starch and soluble sugars at the graft junction. The success rate in autografts was higher than that of homografts and heterografts. Unfunctional homografts and heterografts showed similar responses: absence of vascular reconnections and lack of adhesion between scion and rootstock, even though callus cell clusters and differentiation of new vasculature were produced. The scions of unfunctional grafts accumulated more starch and soluble sugars than the rootstocks, showing a strong asymmetry in the response. In addition, three types of deposits were observed in the cell walls of unfunctional grafts: lignin, suberin, and callose, with the combined accumulation of more than one of them being frequent, particularly lignin and suberin. These deposits apparently prevent adhesion and seem to be a major cause of graft failureSIThis research was funded by the Universidad de León. C.F. acknowledges the PhD grant from the FPU program of the Spanish Science and Innovation Ministry (Ref. FPU18/04934

Histological description of Saxifraga paniculata leaves with special focus on structures that release CaCO3

[EN] Saxifraga paniculata is a subalpine succulent perennial plant arranged in a rosette that is usually found in shallow soil among limestone rocks. Stereoscopic, light and scanning electron microscopy were used to describe the anatomical structure of S. paniculata leaves, paying special attention to structures related to CaCO3 (calcium carbonate) release. Anomocytic stomata are unevenly distributed on each leaf face, being absent in the lower third. The basal leaf margin presents translucent pluricellular trichomes of variable length and width. Towards the apical margin, trichomes become teeth. Both trichomes and teeth are completely covered with whitish CaCO3 crystals. Each tooth has a circular cavity connected to a single hydathode through pores. Clearing treatment revealed camptodromous leaf venation. Anatomical structure shows a bifacial cross-section with spongy mesophyll cells at basal part, becoming heterogeneous at the apex with palisade mesophyll on the adaxial face. Hydathodes are epithematic and connected to outer cavities via two kidney-shaped guard cells showing large substomatal cavity. The epithem is surrounded by a thickened sheath and is formed of highly packed elongated cells with interspersed tracheary elements. CaCO3 deposits consist of microscopic crystals with varying geometries, of which the rhombus is the basic unitSIWe thank the Universidad de León (Spain) for providing the funds for performing this stud

Histological Changes Associated with the Graft Union Development in Tomato

This article belongs to the Section Plant Cell Biology[EN] Despite the importance of grafting in horticultural crops such as tomato (Solanum lycopersicum L.), the structural changes that occur during the graft establishment are little understood. Using histological techniques, the present work examines the time course of changes on the anatomical structure of the graft junction in functional tomato homografts and compares it to that of heterografts and non-functional grafts. No apparent differences were detected between homo- and heterografts, showing similar tissue development. At 10 days after grafting, the cell walls of the scion and rootstock in the area of the graft junction were thicker than usual. Undifferentiated cells and new vascular tissue emerged from the pre-existing vasculature. Adventitious roots appeared mainly on the scion, arising from the pre-existing vasculature. At 20 days, more pronounced vascular tissue was visible, along with large areas showing vascular connection. At 210 days, vestiges of the changes undergone in graft development were still visible. Generally, non-functional grafts presented layers of necrotic remains and deposition of cell wall material in the cut edges, impeding the suitable scion-rootstock connection. Our results show that accurate changes in pre-existing vasculature and the cell walls of the adhesion line are crucial to the development of functional graftsSIThis research was funded by Universidad de León. The APC was funded by Universidad de Leó

Microscopic study of nine galls induced in Populus nigra by aphids of the Iberian Peninsula

[EN] Aphids (Hemiptera, Aphididae) feed on the phloem and some of them induce the formation of conspicuous galls on their primary hosts. Histological studies were proposed to elucidate the evolutionary history of galling habit in Pemphigini tribe, assessing if gall complexity indicates the phylogenetic relations among gall inducers. Nine Eriosomatinae galls induced on Populus nigra from the Iberian Peninsula were studied microscopically. The galls are induced by Pemphigini of the genera Thecabius (2 galls) and Pemphigus (7 galls). Using multiple correspondence analysis of the observed microscopic characteristics, a hierarchical cluster was obtained showing the existence of 2 groups of galls. One group consists of the 2 galls induced by Thecabius and, within the genus Pemphigus, those belonging to the subgenus Pemphigus (P. populi and P. vesicarius). The other group consists of galls of the genus Pemphigus, subgenus Pemphiginus (P. bursarius, P. immunis, P. spyrothecae, P. protospirae and P. populinigrae). The gall histological complexity is related to Pemphigini phylogeny, confirming the importance of such studies in galling aphid taxonomy and possible pathways of galling habit evolution. Similarities are established between the galls of Pemphigini aphids studied here with others we studied microscopically, induced by Fordini and Eriosomatini. Finally, a classification of all Eriosomatinae galls is proposed, establishing 3 groups: galls that cause severe malformations (induced by derived galling taxa), those that cause less severe malformations, and those that cause mild malformations (pseudogalls). It also demonstrates the importance of the strategy of waste evacuation in derived galling speciesS

Applications of bioclimatology to assess effects of climate change on viticultural suitability in the DO León (Spain)

[EN] Spain accounts for 13.1% of the world’s vineyard area, and viticulture is crucial for the socioeconomic and cultural sectors. Vineyards are among the perennial crops that can suffer most negative impacts under climate change which can pose challenges to the sustainability of viticulture. Local and regional studies are needed to assess these impacts to help implement effective strategies in response to climate change. To this end, our approach involves integrating both conventional agroclimatic indices and those new bioclimatic indices that have proven to be essential for the characterization and demarcation of vineyards into species distribution models to assess areas suitable for viticulture under climate change projections. The proposed methodology was tested in a viticultural region located in northwestern Spain (DO León). An ensemble platform was used to build consensus models encompassing three general circulation models, two emission scenario pathways and two time horizons. Only the predictors that effectively characterize each grape variety were included in the models. The results revealed increases in the continentality index, compensated thermicity index, hydrothermic index of Branas, and temperature range during ripening in all the future scenarios analyzed in comparison to current conditions. Conversely, the values for the annual ombrothermic index and growing season precipitation may decrease in the future. The pattern of changes for 2070 will be more pronounced than for 2050. A significant loss of future habitat suitability was detected within the limits of the study area for the grape varieties analyzed. This negative impact could be counteracted to some degree with new and favorable areas for the cultivation of vineyards in territories located at the north of the DO limits. We suggest that our results could help policymakers to develop practices and strategies to conserve existing grape varieties and to implement efficient adaptation measures for mitigating or anticipating the effects of climate change on viticulture.SIThis work was supported by the Regional Ministry of Education, Junta de Castilla y León (Spain), EDU/667/201