Effects of banding mixed forest on activity of defensive proteins in Larix olgensis

  Objective  To illuminate the effects of allelogenicity of Fraxinus mandshurica on defense proteins of larch in mixed forest, the activities of defensive proteins in larch conifers of banding mixed forest types with Fraxinus mandshurica were analyzed.

  Method  Taking Larix olgensis as the control, that planted in pots and in the ground was mixed with Manchurian ash in 1∶1, 3∶3 and 5∶5 (HJ_1∶1, HJ_3∶3, HJ_5∶5) bands, respectively. One year later, the activity of defense proteins in the needles of Larix olgensis was measured by ultraviolet spectrophotometer.

  Result  The activities of defense proteins in needles of three kinds of banded mixed Larix olgensis planted in the field and pot were higher than those in the control. The activities of phenylalanine ammonia lyase (PAL), chymotrypsin inhibitor (CI), trypsin inhibitor (TI) and polyphenol oxidase (PPO) in HJ_3∶3 needles were always higher than those in the control (P<0.05). Except August 1, the PPO activity in the needles of HJ_3∶3 planted in the field was significantly higher than that in control (P<0.05), and there was no significant difference between HJ_3∶3 and HJ_5∶5 (P>0.05). The activity of defense protein in potted HJ_3∶3 needles was always higher than that in the control (P<0.05), and HJ_3∶3 was significantly higher than HJ_1∶1 or HJ_5∶5. Compared with pot culture, field planting HJ_5∶5 was more beneficial to increase PAL activity in needles. However, the effects of HJ_1∶1 on PPO activity in needles and HJ_5∶5 on CI activity in needles were relatively small.

  Conclusion  The zonal mixing with Fraxinus mandshurica can improve the activity of defense protein in the needles of Larix olgensis, and the HJ_3∶3 mixing mode has the most significant effect, and its defensive protein activity is significantly enhanced.