The number of pre-bloom, bloom and fruit-set source leaves are the most important determinant of tolerance of buds to low temperatures during winter. In this study, we tested whether pre-bloom (LR-PB), bloom (LR-FB) and fruit-set (LR-FS) hand defoliation are effective in interacting the cold hardiness and biochemical parameters in dormant buds (basal-medium and apical buds) of a high-yielding cultivar Karaerik during period of 2-year field study. In the LR-PB contrary to control (C) was found that basal-medium buds showed high-temperature exotherm (HTE) values and low-temperature exotherm (LTE) values at high temperatures than apical buds; therefore, basal-medium buds (1st, 2nd, 3rd, 4th and 5th) had less tolerance to low temperature than apical buds (6th, 7th, 8th, 9th and 10th). Additionally, the contents of the soluble carbohydrates increased in buds apical after the LR-PB treatment, while malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and superoxide radical (O₂^·−) were decreased. The results from defoliation indicated that the LTE values are positively correlated with water content, MDA, H₂O₂ and O₂^·− and are negatively correlated with soluble carbohydrates content. Particularly, LR-PB treatment played the key role to explain the difference of cold hardiness between basal-medium and apical buds. Therefore, since LR-PB treatment does not have a negative effect on basal bud survival and increases the survival of apical buds in cool climatic regions, it could be used as a powerful technique for grape cultivars with poor basal buds fruitfulness.

开花前，开花和结实的源叶数量是冬季芽对低温耐受性的最重要决定因素。在这项研究中，我们测试了开花前（LR-PB），开花（LR-FB）和坐果（LR-FS）的手脱叶是否有效地相互作用了休眠芽中的耐寒性和生化参数（基础培养基）高产栽培品种Karaerik在2年的田间研究期间。在LR-PB中，与对照（C）相反，发现基生芽在高温下比顶芽显示出高温放热（HTE）值和低温放热（LTE）值。因此，中型芽（第一，第二，第三，第四和第五）对低温的耐受性低于顶芽（第六，第七，第八，第九和第十）。另外，₂ O ₂）和超氧自由基（O ₂ ^·−）减少。从落叶结果表明，在LTE的值具有正的水含量，MDA，相关ħ ₂ ö ₂和O ₂ ^{· -}和存在负的可溶性碳水化合物含量相关。特别是，LR-PB处理在解释基础培养基和顶芽之间的耐寒性差异方面起着关键作用。因此，由于LR-PB处理不会对基础芽的存活产生不利影响，并且不会增加气候凉爽地区根尖的存活，因此它可以用作基础芽收效差的葡萄品种的有力技术。