Advances on salinity responses and tolerance in citrus

Citrus is a major horticultural crop and is very salt sensitive. The review summarized the differ-ence of salt tolerance of citrus germplasm. The adverse effects of salinity on physiological aspects of citrusare also summarized. Salinity causes water deficit in plants,and causes specific ion toxicity especially theCl-toxicity. Besides,salinity affects the absorption of mineral elements and finally leads to nutritional im-balance within plants. During the long-term evolution process,citrus plants have developed some toler-ant mechanisms to cope with salt stress. For example,biosynthesis of sugar alcohols and amino acids con-tribute to osmotic adjustment in citrus under salinity stress,and enzymatic system and some oxidants(non-enzymes) can help to reduce the damage from reactive oxygen species. Furthermore,the ion trans-porters such as ATP-binding cassette transporter(ABC) and Chloride channel(CLC) are involved in rees-tablishment of ion homeostasis,which also play important roles in adaptations of citrus under salt stress.