만개기 단근처리를 통한 수분스트레스가 '후지'/M.9 사과나무의 수체반응 및 과실특성에 미치는 영향

Abstract

본 시험은 5~6월 수분스트레스가 사과나무의 광합성, 신초생장 및 과실품질에 미치는 영향을 구명하고자 실시하였다. 단근은 만개기(4월 30일)에 원줄기에서 30cm와 60cm 떨어진 곳에서 열 방향에 따라 양쪽 혹은 한쪽으로 처리 하였다. 무처리구의 5~6월 오후 평균 잎수분포텐셜은 -1.80MPa 이상을 유지하였지만, 단근 처리구들은 -1.80MPa 이하였다. 단근 처리 정도에 따른 5~6월경 오후 평균 잎 수분포텐셜은 양쪽 30cm 단근구(-2.06MPa), 양쪽 60cm 단근구(-2.02MPa), 한쪽 30cm 단근구(-1.91MPa) 순으로 낮았다. 한쪽 30cm 단근 처리와 양쪽 30cm 단근 처리는 5~6월 광합성속도를 각각 무처리구의 80% 및 65% 수준으로 감소시켰다. 또한, 한쪽 30cm 단근구의 무처리구 대비 총 신초장과 평균 과중의 감소 정도는 각각 25% 및 11% 정도였던 반면에 양쪽 30cm 단근구는 각각 45% 및 15% 정도였다. 그러나 가용성 고형물 함량 및 착색 정도는 단근 처리구들이 무처리구보다 높았으며, 양쪽 단근구들이 한쪽 단근구보다 더 높았다. 결론적으로, 5~6월 오후 평균 잎 수분포텐셜이 -1.80MPa 이하이면 과실비대가 감소되었고, -2.00MPa 이하이면 신초생장이 감소되었다. This study was conducted to find out the influence of water stress from May to June on photosynthesis, shoot growth and fruit quality of apple trees. Fuji'/M.9 apple trees were root pruned at full bloom (30th April), parallel to the row of 30 cm or 60 cm from the trunk, to one side or both sides of trunk. The average value of afternoon leaf water potential from May to June of the no root pruning was maintained over -1.80 MPa, but that of root-pruning treatments was maintained under -1.80 MPa. In the comparison of average value of leaf water potential from May to June by root-pruning degree, the root pruning both sides at 30 cm from trunk was lowest (-2.06 MPa), followed by the root pruning both sides at 60 cm (-2.02 MPa) and the root pruning one side at 30 cm (-1.91 MPa). Root pruning one side at 30 cm or both sides at 60 cm reduced photosynthetic rate from May to June by 80% or 65%, respectively, compared with no root pruning. So, the degree of decreasing total shoot length or average fruit weight compare to the no root pruning of the root pruning one side at 30 cm was 25% or 11%, respectively, and those of the root pruning both sides at 30 cm was 45% or 15%, respectively. However, the soluble solid content and fruit color of the root pruning was higher than those of the no root pruning, and those of the root pruning both sides was higher than root pruning one side. These results indicate that the fruit enlargement was decreased when the average value of average leaf water potential from May to June was under -1.80 MPa, and the shoot growth was decreased when that was under -2.00 MPa.