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Pak. J. Bot., 48(4): 1431-1438, 2016.

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THE EFFECTS OF A PLANT GROWTH REGULATOR, LEAF REMOVAL, BAGGING, AND HARVEST TIME ON THE LIPOXYGENASE ACTIVITY AND FATTY ACID COMPOSITION OF PINOT NOIR GRAPEVINES

YANLUN JU¹, JIE ZENG¹, MEIRONG ZHU¹, XIAOTONG LV¹, TONGMENG WANG¹,

ZHENWEN ZHANG^1,2, HUA LI^1,2 AND YULIN FANG^1,2

¹College of Enology, Northwest A&F University, Yangling, Shaanxi 712100, China

²Shaanxi Engineering Research Center for Viti-Viniculture, Yangling, Shaanxi 712100, China

Abstract

Green leaf volatiles (GLVs) are an important source of grape aromas, and lipoxygenase is a key enzyme involved in the formation of green leaf volatile substances. In addition, fatty acids are the main substrates that compose GLVs and are the main precursor compound utilized in the formation of grape aromas, which are an important index of grape quality. We examined the effects of a plant growth regulator, leaf removal, bagging, and harvest time on the lipoxygenase (LOX) activity, and the fatty acid composition of grapevines were studied. The following four experimental treatments were conducted using Pinot Noir (Vitis vinifera L.) grapevines to study the following variables: treatment with a plant growth regulator, leaf removal, fruit bagging, and harvest time. We obtained the following results. (1) 16 types of fatty acids were detected in the grape skins. The unsaturated fatty acid content consisted mainly of linoleic acid, oleic acid and palmitoleic acid; however, no linolenic acid was detected. In addition, the saturated fatty acid content consisted primarily of palmitic acid, stearic acid, behenic acid and arachidic acid. (2) Abscisic acid (ABA), methyl jasmonate (MeJA), light intensity, and harvest time appeared to effect LOX activity. (3) According to a principal component analysis (PCA) of the four treatments and the fatty acid content of the skins, ABA (concentration of 1000 mg/L), MeJA (concentrations of 100 µmol/L, 400 µmol/L and 800 µmol/L) and early harvest treatment were responsible for the changes in fatty acid content. These results could be helpful in vineyard management and in improving the quality of grapes.

Key words: Plant growth regulator, Pinot noir; Lipoxygenase; Fatty acid; PCA.