Effects of Three Disease Resistance Inducers on Leaf Growth, Disease Resistance and Related Enzyme Activities of Lycium barbarum

PurposeTo study the effects of three disease resistance inducers including acetylsalicylic acid (ASA), methyl jasmonate (MeJA) and β-aminobutyric acid (BABA) on leaf growth and disease resistance of Lycium barbarum.

MethodsWith 6-year-old ‘Ningqi VII’ as experimental material, ASA, MeJA and BABA were sprayed on the leaves as treatment, spray 0.5% Tween-80 as control. The induction cycle was seven days after one spraying, and a total of five times were induced. The leaf area, leaf thickness, chlorophyll content, SOD activity, POD activity, PAL activity, flavonoid content and other indexes were measured by sampling at three, four and five times of induction, and investigation of leaf spot disease incidence of L. barbarum at the end of five inductions, to analysis the effects of different inducers on the natural disease, leaf growth, active oxygen metabolism, phenylpropane metabolism and cell membrane oxidation degree of L. barbarum.

ResultsSpraying 0.3 mmol/L MeJA on leaf surface significantly decreased the natural incidence and disease index of leaf spot disease of L. barbarum. Three inducers increased the chlorophyll content and leaf area of L. barbarum, and decreased the leaf thickness. The induction times of three inducers were different when the induction effect was the best. ASA and MeJA had the best induction effect after three times, increasing SOD activity by 65.85% and 76.34%, POD activity by 54.72% and 20.38%, PAL activity by 10.84% and 38.28%, respectively; the content of total phenols increased by 7.43% and 29.14%, flavonoids increased by 4.21% and 35.74%. BABA had the best induction effect after five times, increasing SOD activity, POD activity and PAL activity by 72.56%, 72.34% and 41.76%, respectively, increasing the content of total phenols and flavonoids by 48.32% and 53.39%, respectively.

ConclusionThere are three types of inducers that can stimulate the leaves of L. barbarum to produce reactive oxygen species, increase the activity of antioxidant enzymes, protect the integrity of cell membrane, increase PAL activity and accumulation of total phenols and flavonoids, and improve disease resistance. Meanwhile, MeJA needs less induction times and has better induction effect, so it has more application value in production.