본 연구는 적외선 열 영상 장치를 이용하여 2년생 ‘유미’ 복숭아나무의 토양수분 수준에 따른 엽온 및 CWSI를 분석하여 수분스트레스 측정 가능성을 검토하였다. 엽온은 대기온도와 유사한 일변화를 보이며 낮 시간대에는 대기온도보다 높은 양상을 보였다. 엽온은 전일(24시간) 기준으로 대기온도(r2 = 0.95), 일사량(r2 = 0.74), 상대습도(r2 = -0.88)와 모두 높은 상관계수를 나타났다. 또한 토양수분장력은 낮 시간대(11~16시)에 엽온(r2 = -0.57), 엽-대기온도차(r2 = -0.71), CWSI(r2 = -0.72)와 높은 부의상관을 나타냈다. CWSI와 엽온, 엽-대기온도차의 상관계수는 24시간 기준으로 매우 높았고(r2 = 0.90, r2 = 0.92), CWSI와 토양수분장력의 상관분석에서 24시간 기준으로는 상관관계가 낮았으나(r2 = -0.27), 낮 시간대(11~16시)에는 상관관계가 매우 높았다(r2 = -0.72). CWSI (y)와 토양수분장력(x)의 상관관계 결정계수(r2)는 11~12시간대에 가장 높았으며(r2 = 0.68), 이때 회귀식은 y = -0.0087x + 0.14로 조사되었다. 일반적인 토양수분스트레스 시점인 -50 kPa에 해당되는 CWSI는 0.575로 계산된다. 따라서 적외선 열 영상 장치를 이용한 엽온 및 CWSI는 토양수분장력에 대해 높은 상관계수를 나타낸 것으로 보아 복숭아나무의 수분스트레스 진단에 유용하게 활용할 수 있을 것으로 예상된다.

Nitrogen is a key component in the growth of crop plant. To increase the yield of crops, an enormous amount of nitrogen fertilizer is currently being used, which increases the total production cost and leads to environmental pollution by the residual nitrogen sources. For these reasons, researchers have tried to improve the crop’s nitrogen use efficiency (NUE) as a solution for reducing the amount of nitrogen fertilizer used. MicroRNAs are a class of small non-coding RNAs regulating the expression of target genes. Recent studies suggested that the expression pool of microRNAs changes in response to a variety of nutrient deficiencies and that such changes play important roles in adapting to or resisting the consequential nutritional stresses. Here, we aim to identify and characterize rice microRNAs whose expression changes upon nitrogen starvation and re-supplementation. By applying RNA-Seq, we observed that the expression of a set of genes involved in nitrogen assimilation was altered in response to nitrogen deprivation. We also found that a considerable number of microRNAs exhibited dynamic expression changes in a nitrogen supply state-dependent manner and that the expression of genes targeted by those differentially regulated microRNAs was altered reciprocally. Our study suggests that microRNAs may have roles in regulating the response of rice to nitrogen supply state and subsequently modulating NUE.

The biosphere of the earth is not only about to overpass the limit to meet the food demand of the world but also the stability of its food production has been also jeopardized by the disasters and pests, especially by the unpredictable weather disasters. In addition the agricultural and industrial pollution against biosphere aggravates the unstability of agricultural production and constitutes a threat in securing the food of the world. In Korea the yield level of crops has been greatly enhanced by the improved agrotechnologies and varietal improvement, but the yield variability due to unfavorable weather events and pests remained unchanged with the change in time. Among weather-related disasters the drought and flood damages has occurred most frequently and impacted most greatly on the agricultural production and its stability. During last decade (1970-l980) the rice production experienced the average annual loss of 0.544 million metric ton which was composed of 0.21 million M/T by climatic disaster, 0.21 million M/T by disease and 0.12 million M/T by insects, and the annual loss of upland crop production from climatic disasters amounted to 0.06 million metric tons. Especially in 1980, the global climatic disasters due to cold or hot temperature endangered the agricultural production all over the world and also the rice production of Korea recorded the unprecedented yield reduction of about 30 percent due to cool summer weather. Nowadays, the unusual weather conditions are prevaling throughout the world, and agro-meteologists predict that the unpredictable cool summer and drought will often attack the rice and other crops in 1980's. To meet the coming weather unstability and to secure the stable crop production, multilateral efforts should be rendered. Therefore, the Korea Society of Crop Science, which commemorates the 20th anniversary of its founding, prepared the symposium on Meteological Stress in Crop Production and its Countermeasures to discuss the decrease in agricultural production due to weather-related disasters and to devise the multilateral counter-measures against the unfavorable weather events.