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Castor bean ( Ricinus communi s) is one of the most important candidate crops that can be used to increase the land cover and crop yield in the arid and saline region of China. To evaluate the effects of arbuscular mycorrhizal (AM) fungi on the growth of castor bean under drought and salt stresses, a pot experiment was carried out to examine how AM fungi improve the plant growth of castor bean by affecting the leaf gas exchange, pigments, and metabolites accumulation of castor bean seedlings. The results showed that AM fungi stimulated plant growth and increased the castor bean aboveground biomass. AM fungi significantly increased the net photosynthetic rate ( A ), stomatal conductance ( g s ) and transpiration rate ( E ) of castor bean and decreased the intercellular CO 2 concentration ( Ci ) under drought and salt stress. The contents of chlorophyll a , chlorophyll b , chlorophyll a  +  b and carotenoids in leaves treated by AM fungi were higher than in those without the AM fungi treatment. AM fungi notably increased the soluble protein and proline contents and decreased the malondialdehyde (MDA) content of castor bean. The results indicated that AM fungi could protect castor bean against drought and salt stresses by improving its leaf gas exchanges and photosynthetic capacity and altering its concentrations of metabolites. Our results highlight that AM fungi might be a promising bio-approach that can be used to plant castor beans in northeast and northwest China. [ABSTRACT FROM AUTHOR]

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy ). This article has been retracted at the request of Editor-in-Chief Marisol Berti in agreement with Editor-in-Chief Maria Jesus Pascual Villalobos. The article has been retracted due to ‘salami slicing publication’. Part of apparently the same study was submitted 10 days earlier and published in Industrial Crops and Products 95(1) (2017) 156-162. ( http://dx.doi.org/10.1016/j.indcrop.2016.09.049 ). The authors accepted this decision and apologized for the trouble caused. As a consequence, pages 42-45 originally occupied by the retracted article are missing from the printed issue. The publisher apologizes for any inconvenience this may cause. [ABSTRACT FROM AUTHOR]

Optimization of nitrogen fertilizer application is an important means of improving castor ( Ricinus communis L.) yield. The method of nitrogen application with drip irrigation under mulch film (DI) differs from that of standard cultivation practices. A field experiment was conducted in 2013 and 2014 to investigate the effects of different nitrogen treatments (0, 100, 200, 300, and 400 kg N ha −1 ) on castor yield, nitrogen use efficiency, and dynamic changes in the spatial distribution of roots under DI. The main objective was to determine the effectiveness of nitrogen fertilizer application for simultaneous improvement of the nitrogen use efficiency and productivity of castor. Yield showed a distinct increase with elevation in nitrogen application rate. The highest yields of 5939.3 and 5812.1 kg ha −1 were attained under nitrogen application of 300 kg N ha −1 in the 2013 and 2014 cropping seasons, respectively. However, application of 400 kg N ha −1 did not further increase yield. Root length increased gradually with increasing nitrogen application from 0 to 200 kg N ha −1 . Under 200 kg N ha −1 , maximum root length was observed and the root length density in the soil was most widely distributed in the entire soil profile, which may account for the high nitrogen use efficiency observed in this treatment (72.4% and 67.4% in 2013 and 2014, respectively). The difference in yield between the 300 kg N ha −1 and 200 kg N ha −1 treatments was not significant. The results suggest that the optimal nitrogen application for castor under DI is between 200 and 300 kg N ha −1 to improve yield and nitrogen use efficiency simultaneously. [ABSTRACT FROM AUTHOR]

• Apocynum is widely distributed and geographically diverse plant species. • Apocynum exhibits several medical and economic benefits. • Salt tolerance in Apocynum is associated with better redox- and osmo-regulation. • Apocynum can be used to remediate saline area due to its better ability to remove salts from soil and sequester in leaves. • Both sexual and asexual propagation methods make Apocynum cultivation a great opportunity for the vegetation restoration on saline soils Apocynum belongs to Apocynaceae family, is known as highly stress tolerant plant genus. Apocynum venetum L. and Apocynum pictum Schrenk, locally known as luobuma in China, are used as traditional medical plants and cash crops, and used for the phytoremediation of degraded saline lands. This review was aimed to critically analyzed the biological uses, salt tolerance mechanisms, and propagation methods of both Apocynum species to highlight the significance of the cultivation of Apocynum as a great opportunity for the vegetation restoration in saline soils in the arid region. In saline area, where arable crop production is nearly impossible due to high salt toxicity in soil, cultivation of Apocynum can reduce the levels of salt in soils and can also provide livelihood in the form of high-quality fibre. Critical literature analysis showed that overall salinity tolerance in Apocynum is associated with the regulation of redox regulation and ionic homeostasis, however their molecular regulation has not been identified yet. Findings such as removal of Na+ from soils and enhanced accumulation of flavonoids and antioxidants in leaves under saline environment, are useful in understanding the complex network of salt tolerance in Apocynum. Moreover, the practical adoption and application of different sexual and asexual propagation methods also play an important role in the successful cultivation of Apocynum in saline soils. To sum up, there are broad prospects for vigorously developing Apocynum industry by utilizing saline-alkali lands and carrying out research on cultivation technology and conservation strategy of Apocynum resources in arid lands. [ABSTRACT FROM AUTHOR]