Effects of foliar spray of trace and rare earth elements on mineral elements and main volatiles in developing grape berries

【Objective】The present study aimed at the effects of foliar spray with trace elements(TEs) andrare earth elements(REEs) on the contents of main volatiles in‘Cabernet Sauvignon'(V. vinifera L. redcultivar) and‘Chardonnay'(V. vinifera L. white cultivar) berries,respectively.【Methods】The TEs solu-tion consisted of six elements and the REE solution composed of 15 elements were respectively sprayedon the leaves around berry clusters in four different periods. The treatment with water was taken as thecontrol. Grape berries were collected in three different periods. The contents of mineral elements in thetreated and non-treated grape berries were examined through Inductively coupled plasma-mass spectrom-etry(ICP-MS). Main volatile compounds were analyzed by the technique of headspace solid phase micro-extraction(HS-SPME) combined with gas chromatography-mass spectrometry(GC-MS).【Results】Similarabsorbance for minerals was observed in these two grape cultivars. Among six TEs applied,Mo elementincreased significantly and the content of Cu element obviously enhanced only at either higher concentra-tions or with more frequent spraying. Other four elements presented irregular variation in TEs-treated ber-ries and lacked the similarity between the two cultivars. The contents of REEs in grape berry all exhibitedan accumulative increase along with application concentration and frequency. As for‘Cabernet Sauvi-gnon',the foliar application of TEs significantly reduced the concentrations of(E)-2-hexen-1-ol,(Z)-3-hexen-1-ol and 1-hexanol in the grape berries of 11 th week after flowering(WAF),and markedly en-hanced the concentrations of(E)-2-hexenal and hexanal at harvest. But as for‘Chardonnay',the threeC6 alcohols were significantly increased in unripe berries when TEs were foliar-sprayed,and five C6com-pounds all had no significant difference between the treated and control berries at harvest. The treatmentof REEs significantly reduced the content of(E)-2-hexenal in the grape berries of the two cultivars at11-week. But at harvest,the contents of other four C6 compounds were similar statistically between the REEstreated berries and the control,except that hexanal was increased by REE spraying. The concentrations ofterpenes and β-damascenone in the two grape cultivars were not altered significantly for the spraying ofeither TEs or REEs.【Conclusion】These observations indicate that mineral elements mainly affect the ac-cumulation of C6 volatiles with green leaf odor in grape berry,and have almost no influence on the produc-tion of terpenes or β-damascenone with floral and fruity odor.