Response Of "Nan Yan 1" Aloe Vera To Seawater

Two Aloe vera cultivars (F0 and F50) were cultivated in tidal flat and each was irrigated with freshwater or 60% seawater respectively. Experiments were conducted in two cultivars to assess the differences of response to seawater stress, such as fresh weight and dry weight, the contents of Na⁺, K⁺, Mg⁺⁺, Ca⁺⁺, phytochroms, malondialdehyde, plasma-membrane permeability and antioxidant enzymes activities. Antioxidant enzymes include superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione reductase (GR). Besides, the difference of genes between two cultivars was analyzied by RAPD. The present investigation offers a theoretical basis on which the further study of the development of the salt tolerant crops and the utilization of the seabeach can be directed.The results indicate that under 60% seawater irrigation, more dry matter was accumulated in F₅₀ leaves than that in the F₀ leaves, less Na⁺ content and higher K⁺ content caused higher K⁺/Na⁺ and less Na⁺/Ca⁺⁺ in the former. Seawater also increased less plasma-membrane permeability and MDA content of leaves in F50 comparing with F0. Moreover, ratios of chl a/chl b and car/chl in F50 leaves were higher than that in F₀ leaves. In addition, SOD and CAT activities were decreased both in F₀ and F₅₀. POD activity was increased obviously in F50, however, decreased in F₀. GR activity was increased significantly in F₀ and F₅₀. It was obvious that activities of SOD, POD, CAT and GR were all higher in F₅₀ than that in Fo. Therefore, F₅₀ had a relative growth superiority to F₀ in a certain extend due to more dry matter accumulation, higher K⁺/Na⁺ ratio, lower Na⁺/Ca²⁺ ratio, higher ratios of chl a/chl b and car/chl, and higher antioxidant enzyme activities. In present research, there was no genetic difference was observed between two Aloe vera cultivars, implying that the adaptive growth of F₅₀ was probably due to the inductively expression of the salt tolerance genes.