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Abstract The different propagation systems for litchis are reviewed. After examining the main morphological and developmental characteristics of the plant and the description of the structures and materials, including types of substrate required for the propagation of this species, the different methods for its propagation are discussed. Propagation by seeds is only used for breeding or research purposes or for raising rootstock for grafting. Although propagation by cuttings is done in many countries and stooling has been reported as highly successful in India, air layering is the most common commercial way of propagation for this species. Despite that the cambium activity varies from place to place around the stem with only 30% of the cambium being active at any one time grafting is of current use in China.

Background: The outbreak of novel coronavirus pneumonia 2019 (COVID-19) has caused millions of deaths worldwide. It is well documented that troponin predicts the prognosis of patients. Myoglobin is not only an important marker of myocardial injury, but it indicates systemic muscle damage. However, its relationship with COVID-19 was rarely reported. The present study compared the predictive value of troponin and myoglobin on the final prognosis of COVID-19 patients by analyzing the clinical characteristics and serum levels of myoglobin and troponin in severe/critical COVID-19 patients., Methods: We enrolled 499 consecutive eligible hospitalized patients with severe/critical COVID-19 from February 14 to March 24, 2020 at Leishenshan Hospital, Wuhan, China. Clinical characteristics and laboratory data were collected and compared between the patients who died and survived. We analyzed the receiver operating characteristic curves of myoglobin and troponin. Then, the patients were divided into myo + group, myo - group, tro + group, and tro - group, and survival curves were analyzed. The prognostic predictable values of myoglobin and troponin were further analyzed using Cox multifactorial analysis., Results: Myoglobin and troponin were significantly elevated in the death group (134.4 [interquartile range (IQR) 24.80, 605] vs 38.02 [IQR 3.87, 11.73]ng/ml, p<0.001), and troponin was also significantly elevated in the death group (0.01 [IQR 0.01, 0.01] vs 0.04 [IQR 0.02, 0.15]ng/ml, p<0.001). The ROC curves demonstrated that the area under the curve when using myoglobin to predict patient death was 0.911, with a threshold of 1.17, which was equivalent to troponin. Kaplan-Meier survival analysis revealed a significantly lower survival curve in the myo + group than the myo - group. Multifactor Cox survival analysis showed that troponin was no longer significant (HR=0.98, 95% CI 0.92-1.03, p=0.507), but elevated myoglobin was an independent predictor of death in COVID-19 patients (HR=1.001, 95% CI 1.001-1.002, p<0.001). The analysis of the Cox model for predicting patient death and plotting decision curves suggested that the single factor myoglobin model was superior to troponin, and the predictive value of the multifactor model was superior to the single-factor analyses., Conclusions: In severe/critical COVID-19 patients, myoglobin and troponin were predictors of mortality and the probability of conversion to critical illness, and myoglobin may be superior to troponin for predictive value., (Copyright © 2021 The Authors. Published by Elsevier España, S.L.U. All rights reserved.)