Anatomia e ultra-estrutura foliar de Cyperus maritimus Poir. (Cyperaceae): estratégias adaptativas ao ambiente de dunas litorâneas Leaf anatomy and ultrastructure of Cyperus maritimus Poir. (Cyperaceae): adaptive strategies for coastal dune environment

Foram analisados aspectos anatômicos e ultra-estruturais foliares de Cyperus maritimus Poir. visando identificar caracteres adaptativos ao ambiente de dunas litorâneas. Para isto, indivíduos ocorrentes nas dunas da Praia de Pipa, Rio Grande do Norte, Brasil, tiveram as folhas submetidas a diferentes análises: microscopia de luz, eletrônica de varredura e de transmissão. Em vista frontal, a epiderme possui tricomas unicelulares, corpos de sílica, cutícula estriada e depósitos de cera. Em secção transversal, a epiderme é unisseriada com parede periclinal externa espessa. Os estômatos são paracíticos, podendo o ostíolo estar obstruído por cera. Abaixo da face adaxial observa-se o parênquima aqüífero. Os feixes vasculares ocorrem em múltiplas fileiras, sendo as periféricas compostas por feixes de diâmetro menor que os feixes da fileira central. Foram observados caracteres relacionados à síndrome Kranz do tipo clorociperóide. Aspectos ultra-estruturais, como cloroplastos presentes na bainha do feixe, esses sem grana evidentes, entre outras características, reforçam a possível ocorrência da via C4 nesta espécie. É a primeira citação para o gênero Cyperus de cloroplasto nas celulas do tecido vascular. Neste trabalho foi possível observar vários caracteres importantes para plantas submetidas a estresse hídrico e salino, como: cera, células epidérmicas com parede periclinal externa espessada, parênquima aqüífero e síndrome Kranz.<br>Anatomical and ultrastructural aspects of Cyperus maritimus Poir. were analyzed with the aim of identifying adaptive features for the dune environment. Collections were made at Pipa beach, Rio Grande do Norte, Brazil. Leaves were submitted to different analyses: light microscopy, scanning and transmission electron microscopy. In frontal view, the epidermis has unicellular trichomes, silica bodies, a striate cuticle and wax deposits. In transverse section, the epidermis is uniseriate with thickened outer periclinal walls. The stomata are paracitic and the pore sometimes obstructed by wax. Under the adaxial epidermis, there are several layers of aqueous parenchyma. The vascular bundles occur in multiple rows, the peripheral row having bundles with narrower diameters than the central row. Characters related to Kranz syndrome of the chlorocyperoid type were observed. Ultrastructural features support a possible C4 pathway in this species. This work is the first citation of chloroplasts in the cells of the vascular system for the genus. In this study, it was possible to observe several important features of plants submitted to water and salt stress, such as: wax, thickened outer periclinal walls of the epidermal cells, aqueous parenchyma and Kranz syndrome

Measurement of single-diffractive dijet production in proton–proton collisions at √s=8Te with the CMS and TOTEM experiments

Measurements are presented of the single-diffractive dijet cross section and the diffractive cross section as a function of the proton fractional momentum loss ξ and the four-momentum transfer squared t. Both processes pp→pX and pp→Xp, i.e. with the proton scattering to either side of the interaction point, are measured, where X includes at least two jets; the results of the two processes are averaged. The analyses are based on data collected simultaneously with the CMS and TOTEM detectors at the LHC in proton–proton collisions at s=8Te during a dedicated run with β∗=90m at low instantaneous luminosity and correspond to an integrated luminosity of 37.5nb-1. The single-diffractive dijet cross section σjjpX, in the kinematic region ξ&amp;lt; 0.1 , 0.03&amp;lt;|t|&amp;lt;1Ge2, with at least two jets with transverse momentum pT&amp;gt;40Ge, and pseudorapidity | η| &amp;lt; 4.4 , is 21.7±0.9(stat)-3.3+3.0(syst)±0.9(lumi)nb. The ratio of the single-diffractive to inclusive dijet yields, normalised per unit of ξ, is presented as a function of x, the longitudinal momentum fraction of the proton carried by the struck parton. The ratio in the kinematic region defined above, for x values in the range - 2.9 ≤ log 10x≤ - 1.6 , is R=(σjjpX/Δξ)/σjj=0.025±0.001(stat)±0.003(syst), where σjjpX and σjj are the single-diffractive and inclusive dijet cross sections, respectively. The results are compared with predictions from models of diffractive and nondiffractive interactions. Monte Carlo predictions based on the HERA diffractive parton distribution functions agree well with the data when corrected for the effect of soft rescattering between the spectator partons. © 2020, CERN for the benefit of the CMS and TOTEM collaborations

Erratum to: Measurement of exclusive Υ photoproduction from protons in pPb collisions at s NN = 5.02 TeV (The European Physical Journal C, (2019), 79, 3, (277), 10.1140/epjc/s10052-019-6774-8)

In this article the author name Luigi Calligaris was incorrectly written as A. Calligaris. The original article has been corrected. © CERN for the benefit of the CMS collaboration 2022