Rescue of American chestnut with extraspecific genes following its destruction by a naturalized pathogen     

Kim C. Steiner  Jared W. Westbrook  Frederick V. Hebard  Laura L. Georgi  William A. Powell  Sara F. Fitzsimmons 《New Forests》2017,48(2):317-336

Following the near-obliteration of American chestnut (Castanea dentata [Marsh.] Borkh.) by the chestnut blight early in the last century, interest in its restoration has been revived by efforts to develop a blight-resistant form of the species. We summarize progress and outline future steps in two approaches: (1) a system of hybridizing with a blight-resistant chestnut species and then backcrossing repeatedly to recover the American type and (2) transformation of American chestnut with a resistance-conferring transgene followed by propagation and conventional breeding. Several decades of effort have been invested in each approach. More work remains, but results indicate that success is within practical reach. The restoration of C. dentata to its native habitat now appears to be less a matter of time and conjecture than ever before in 90 years of work by public and private entities. The difficult and protracted task of incorporating extraspecific genes for resistance into a tree species with lethal susceptibility to a naturalized pathogen represents perhaps the most extreme of restoration challenges. Its pursuit by a small non-governmental organization supported primarily by philanthropy and volunteers may serve as a model for other species threatened by exotic pathogens or insects.  相似文献   

Root water uptake of pepper plants (Capsicum annuum L.) under deficit irrigation system     

Sara Mardaninejad  Hamid Zareabyaneh  Sayyed Hassan Tabatabaei  Abdolrahman Mohamadkhani 《Journal of plant nutrition》2017,40(11):1569-1579

Root water uptake is a component of water balance that has not been clearly understood. This study was carried out in a completely randomized design with three replications under the greenhouse condition at Shahrekord University, Shahrekord, Iran. In this study, the root water uptake (RWU) by pepper plant under various irrigation water levels was investigated. Irrigation treatments included control (full irrigation level, FI) and three deficit irrigation levels, 80%, 60% and 40% of the plant's water requirement called DI₈₀, DI₆₀ and DI₄₀, respectively. A no-plant cover treatment with three replications was also used to measure evaporation from the soil surface. Daily measurements of volumetric soil moisture (VSM) were made at 10 cm intervals of the soil column. The differences between the measured VSM and the VSM in the next day, and evaporation rate at the soil surface at the same layer of the no-plant cover treatment were calculated and, eventually, the RWU in each layer per day was estimated. The results showed that the maximum and minimum RWUs were found in the FI and DI₄₀ treatments, respectively. The averages of root water uptakes in the DI₈₀, DI₆₀, and DI₄₀ treatments were reduced by 17.08%, 48.72% and 68.25%, respectively. Furthermore, in the DI₈₀ treatment, the reduced rate of water uptake was less than the reduced rate of water applied to the plants.  相似文献   

Standardization of canine meningioma grading: Validation of new guidelines for reproducible histopathologic criteria     

Sara Belluco  Giuseppe Marano  Thibaut Lurier  Giancarlo Avallone  Chiara Brachelente  Stefano Di Palma  Roberta Rasotto  Kerstin Baiker  Andreas Beineke  Anna Oevermann  Frauke Seehusen  Fabiano José Ferreira de Sant'Ana  Patrizia Boracchi  Martí Pumarola  Maria Teresa Mandara 《Veterinary and comparative oncology》2023,21(4):685-699

Canine meningiomas are currently graded using the human grading system. Recently published guidelines have adapted the human grading system for use in dogs. The goal of this study was to validate the new guidelines for canine meningiomas. To evaluate the inter-observer agreement, 5 veterinary surgical pathologists graded 158 canine meningiomas following the human grading system alone or with the new guidelines. The inter-observer agreement for histologic grade and each of the grading criteria (mitotic grade, invasion, spontaneous necrosis, macronucleoli, small cells, hypercellularity, pattern loss and anaplasia) was evaluated using the Fleiss kappa index. The diagnostic accuracy (sensitivity and specificity) was assessed by comparing the diagnoses obtained with the 2 grading systems with a consensus grade (considered the reference classification). The consensus histologic grade was obtained by agreement between 4 experienced veterinary neuropathologists following the guidelines. Compared with the human grading alone, the canine-specific guidelines increased the inter-observer agreement for: histologic grade (κ = 0.52); invasion (κ = 0.67); necrosis (κ = 0.62); small cells (κ = 0.36); pattern loss (κ = 0.49) and anaplasia (κ = 0.55). Mitotic grade agreement remained substantial (κ = 0.63). The guidelines improved the sensitivity in identifying grade 1 (95.6%) and the specificity in identifying grade 2 (96.2%) meningiomas. In conclusion, the new grading guidelines for canine meningiomas are associated with an overall improvement in the inter-observer agreement and higher diagnostic accuracy in diagnosing grade 1 and grade 2 meningiomas.  相似文献