| Purple pepper （Capsicum frutescens L.） belongs to the Solanaceae Capsicum annul orperennial herb, which is a variety of pepper. Its cotyledon, true leaf, stem, flower, tenderfruit and green ripe fruit all take on purple, for containing rich anthocyanin. The top of itsfruit faces up, it can be cherry-shaped, cone-shaped or finger-shaped, and each has adifferent shape. Its plant can resist heat, drought and disease. It can be used as a pottedplant, the landscaping of flower bed, food accessories or natural pigment extractedmaterial.This research analyzed the distribution, the composition, and the stability ofanthocyanin in purple pepper plants, the physiological response of the content ofanthocyanin in leaves to the low light condition and the relation between anthocyanin andplant’s cold-resistance. The main results are as follows:（1） We found that anthocyanin in leaves mainly distributed in the palisade tissue andin the two kidney-shaped guard cells of the lower epidermis stomata.（2） We got two anthocyanidin components which take on purplish red. According tothe physical characteristics of each component, the result can be cyaniding-3-O-glycosidicor cyaniding-3,5-O-biosidic. The former contains two or more acetylation groups while thelatter only has one.（3） The optimal extraction process: the ratio of material to liquid1:2000, extractionsolvent1%hydrochloric acid-methanol, extracted at room temperature, four hours.（4） pH has a greater effect on the stability of anthocyanin. When pH≤3, theanthocyanin has a better stability. It has a certain heat-resistance, but under the condition of80℃or high, it is easy to degrade. In addition, it is sensitive to light. Sunlight has thegreatest effect on its stability, and the next is daylight lamp. Pb2+and Fe3+have a greatereffect on the stability of anthocyanin, many monovalent metal ions and most divalent metalions (Mg2+, Ca2+, Mn2+, Zn2+, Ba2+, Fe2+, Cu2+) as well as Al3+not only improve thestability of anthocyanin, but also have hyperchromic effects. Hydrogen peroxide andascorbic acid do obvious damage to the stability of anthocyanin and have a certain resistance to reducibility on low concentration sodium sulfite. Sodium chloride, sucrose,glucose and citric acid have no effect on the stability of anthocyanin; meanwhile citric acidhas a hyperchromin effect on it.（5） The content of anthocyanin in purple pepper leaves and the illumination intensityare positively correlated with each other. Full exposure can promote the accumulation ofanthocyanin in leaves and it is also good for the emergence of the color of leaves.（6） The lethal temperature of purple pepper is-1.37℃while that of green pepper is-1.35℃, they are similar. But the response of the physiological indexes in test plant leaves,such as MDA, Pro, SOD, POD, CAT, to the low temperature stress is superior to that ofcompared plant. Revealing the anthocyanin in leaves can improve plant’s cold resistance. |
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