嫁接对低温弱光下辣椒幼苗膜脂过氧化及抗氧化酶活性的影响

以‘卫士’为砧木，以‘赤峰特选’为接穂进行嫁接，在光照培养箱内对辣椒自根苗(对照)和嫁接苗进行低温 (8 ℃/5 ℃) 弱光(100 μmol·m^-2·s^-1)处理，处理7 d后在正常条件(25 ℃/18 ℃，550～600 μmol·m^-2·s^-1)下恢复3 d，研究低温弱光下辣椒嫁接苗和自根苗电解质渗漏率(EL)、丙二醛(MDA)含量、抗氧化酶活性及根系活力的变化.结果表明：低温弱光胁迫初期，辣椒幼苗叶片与根系的EL、MDA含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性均显著升高，而根系活力大幅降低；1～3 d后EL和MDA含量趋于平稳，SOD、POD、APX、GR活性逐渐降低，根系活力呈上升趋势.恢复3 d后，嫁接苗EL、MDA含量、抗氧化酶活性及根系活力多达到或超过胁迫前水平(根系的MDA含量较胁迫前略高)；而自根苗的EL和MDA含量仍显著高于胁迫前.与自根苗相比，嫁接苗在各处理阶段的EL和MDA含量显著降低，而SOD、POD、APX、GR活性及根系活力明显升高，说明嫁接可有效降低辣椒植株的膜脂过氧化，减轻低温弱光对其细胞膜的伤害.

Effects of graft on lipid peroxidation and antioxidative enzyme activities of Capsicum annum seedlings under low temperature and weak light intensity

Taking ‘Chifengtexuan’ as scion and ‘Weishi’ as rootstock, this paper studied the changes in the electrolyte leakage (EL), malondialdehyde (MDA) content, antioxidative enzyme activities, and root activity of own-rooted and grafted Capsicum annuum seedlings under 1-7 d ays low temperature (8 ℃/ 5 ℃) and weak light intensity (100 μmol·m^-2·s^-1) stress and after 1-3 d recovery. During the early stress days, the EL, MDA content, and activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) in both own-rooted and grafted seedlings leaves and roots increased, but the root activity decreased significantly. 1-3 days later, grafted seedlings showed a stable state in EL and MDA content, a decrease in SOD, POD, APX, and GR activities, and an increasing trend in root activity. After 3 days recovery, the EL, MDA content, antioxidative enzyme activities, and root activity of grafted seedlings reached or exceeded their original levels, except for the MDA content in roots, while the EL and MDA content of own-rooted seedlings were still significantly higher than those before the stress. Comparing with own-rooted seedlings, grafted seedlings showed lower EL and MDA content, higher activities of SOD, POD, APX and GR, and higher root activity during stress and recovery days. These data suggested that graft could effectively decrease the lipid peroxidation, and alleviate the damage of low temperature and weak light intensity to Capsicum annuum seedlings.