온주밀감의 과실 품질에 미치는 타이벡 멀칭의 효과

Abstract

온주밀감의 과실 품질에 미치는 타이벡 멀칭의 영향의 결과는 다음과 같다. 과즙 내 당도의 변화는 11월 30일 타이벡 멀칭 처리구의 당도는 12°Brix로 가장 높았으며 10월 20일 점적 관수를 해준 멀칭 처리구의 당도는 다소 낮아지는 경향을 나타냈으나 10.5°Brix여서 대조구에 비해서는 0.5°Brix 높았다. 과즙 내 산도의 변화는 11월 30일 타이벡 멀칭처리구의 산도는 1.4%로 가장 높았으며 점적 관수한 타이벡 멀칭구의 산도는 1.0%로 무처리구에 비해 다소 낮았다. 과실 내 호흡속도의 경시적 변화는 9월 30일에 이미 건조처리를 받은 멀칭 처리구는 무처리구에 비해 빨랐으며 11월 30일 에 타이 점적관수한 타이벡 멀칭구는 가장 높았다. 건조 처리 중 잎수분퍼텐셜의 측정치는 -1.1MPa~-2.5MPa 범위로 대조구 보다는 낮게 나타났다. 11월 30일 멀칭처리구의 잎수분퍼텐셜 측정치는 -2.2MPa로 10월 20일 점적관수한 멀칭처리구에 비해 -0.7MPa이상 높게 유지되었다. 사양 조직의 수분퍼텐셜 경시적 변화는 이미 건조하게 관리한 멀칭 처리구의 9월 30일 조사시점의 사낭 조직 수분퍼텐셜은 -1.3MPa이었으며 11월 30일 사양 조직 수분퍼텐셜은 지속적인 증가 추세로 -0.2MPa까지 높아졌으나 대조구보다 다소 낮았다. 사낭조직의 삼투퍼텐셜은 건조 스트레스 받는 9월 30일 조사시점의 사낭조직의 삼투 포텐셜은 -1.4MPa로 대조구에 비해 낮았으며 11월 30일에는 10월 20일 점적관수를 한 처리구와 멀칭처리구의 사양 조직 삼투 퍼텐셜은 각각 -1.2MPa와 -1.4MPa로 대조구에 비해 높게 나타났다. 팽압은 건조하게 관리된 처리구의 사양 조직에서 0.4MPa로 대조구에 비해 다소 높게 나타났으나 수확기인 11월 30일에는 멀칭처리구의 사양 조직의 팽압이 대조구에 비해 높았으나 점적관수를 한 처리구는 여전히 대조구에 비해 낮았다. 과육의 수분함량율은 9월 30일에는 건조하게 관리한 처리구 간에는 차이가 없었으나 조사시점인 10월 30일에는 점적관수한 처리구가 대조구나 멀칭처리구보다 높았고 반대로 건물율은 제일 낮았다. 11월 30일에도 같은 양상으로 10월 30일보다 작은 경향을 보였다.

This study investigated the effect of drought stress on the fruit quality, such as the sugar content and acidity, in the Satsuma mandarin with Tyvex mulching with dryness processing(Mulching 1), compared to Tyvex mulching with trickle irrigation once a week from 20th October after dryness processing(Mulching 2) and no mulching treatment(Control). The results are as follow; In the sugar content of the fruit juices, the content in mulching 1 was 12˚Brix, which was the highest, the content in mulching 2 after starting trickle irrigation marked a down tendency a little, but it was 10.5˚Brix, which was 0.5˚ higher than the control. In the acidity of the fruit juice, the acidity in mulching 1 was 1.4%, which was the higher than the rest, the acidity in mulching 2 was 1.0%, lower than the control. The respiration speed in mulching 1 with dryness processing was slightly quick compared with control, and that of mulching 2 with trickle irrigation marked the highest level on November 30th. The leaf water potentials in mulching 1, 2 during dryness processing were lower than the control, but mulching 2 with trickle irrigation after dryness processing marked 0.7MPa higher than mulching 2 preserved dryness processing. The juice sac water potentials both in mulching 1, 2 were remarkably lower than the control at growing and ripening seasons, but increased rapidly to 0.2MPa at harvest season, to a slightly low degree of the potentials in the control. The osmotic potentials of the juice sac organization of the fruits in mulching 1, 2 were -1.4MPa at growing and ripening seasons, which was lower compared with the control, but at harvest season the potentials in both mulching 2 with trickle irrigation and mulching 1 with dryness processing were -1.2MPa, -1.4MPa respectively, they were higher than that of the control. The tugor pressure of the fruit in mulching 1, 2 were 0.4MPa, slightly higher than the control, at harvest season the tugor pressure in mulching 1 was higher than that in the control, but the tugor pressure in mulching 2 was lower than that in the control. The water content ratios in mulching 1, 2 had no difference in the control at growing season, at ripening season the ratios in mulching 2 was higher than those in mulching 2 and the control, on the contrary the dry rate was lowest. The same order was kept at harvest season. From the study, the fact that the sugar content of the fruit under drought stress increases was verified, it is believed that the increases in the sugar content was caused not by the process of condensation, but by the positive control of the osmotic potentials to deal with the tugor pressure of the fruit affected by drought stress. Also, after trickle irrigation the decreases in the sugar content and acidity was observed, the reason was that the organic acid is used by the material of the respiration process, it was verified by that there was the strong negative correlation between the respiration speed and the organic acid content.