Italian ryegrass (Lolium multiflorum Lam.) is one of the most widely grown winter forage crops in Korea, but its yields are known to be greatly affected by drought that occur frequently in spring. This study aimed to compare the growth and tolerance response characteristics to drought stress in several Italian ryegrass varieties cultivated in Korea. Twenty-day-old Italian ryegrass was subjected to drought treatment for 4 days, and then the growth and physiological responses of the plants were compared. Drought stress reduced leaf length, fresh weight, and dry weight in all Italian ryegrass varieties compared to the control. In addition, chlorophyll content was significantly decreased in all varieties treated with drought stress, but Fv/Fm was significantly decreased only in Winter hawk. For H2O2 and malondialdehyde (MDA) contents, Winter hawk showed the highest increase and New dawn showed the least increase. In terms of relative water content (RWC), New dawn showed the least decrease and Winter hawk showed the greatest decrease. These results indicate that New dawn is relatively drought-tolerant and Winter hawk is a drought-sensitive variety, indicating that each variety of Italian ryegrass has different drought tolerance mechanisms, which may provide basic insight for the development of tolerant varieties in the future.

Drought stress is one of the major factors that reduce plant growth and productivity. This study was conducted to investigate the effect of exogenous acetic acid pretreatment on drought stress tolerance response in plants. Fourteen-day-old alfalfa plants were pretreated with 15 mM acetic acid, and then subsequently subjected to drought stress for 6 days. The fresh weight and relative water content in the leaves of acetic acid pretreated alfalfa plants were increased compared to the control group. The chlorophyll and carotenoid contents were slightly decreased in the acetic acid treatment. The H2O2 and proline contents were also significantly decreased in the acetic acid treatment. These results suggest that the scavenging mechanism of reactive oxygen species in alfalfa activated by acetic acid pretreatment is involved in conferring tolerance to drought stress.

Drought is one of the environmental factors inhibiting plant productivity and growth, leading to oxidative damage. This study aims to identify the role of sodium hydrosulfide (NaHS) as a hydrogen sulfide (H2S) donor in drought stress tolerance in Brassica napus. Drought-induced stress symptoms appeared eight days after treatment, showing wilted leaves and a significant reduction of leaf water potential. Drought-induced increase of lipid peroxidation was significantly reduced by NaHS application. NaHS-treated plants mitigated stress symptoms under drought conditions by reducing hydrogen peroxide (H2O2) content, confirmed with H2O2 localization in situ. Furthermore, NaHS promotes photosynthetic activity by maintaining chlorophyll and carotenoid content, thereby supporting plant growth under drought conditions. Pyrroline-5-carboxylate and proline contents were significantly increased by drought but further enhanced by NaHS treatment, indicating the important roles of proline accumulation in drought stress tolerance. In conclusion, this study provides valuable insight into the roles of NaHS in alleviating drought stress by reducing oxidative stress and promoting proline accumulation. Therefore, NaHS may serve as an effective strategy to enhance crop production under drought-stress conditions.

Pinus densiflora is a fixed-growth coniferous species that elongates its shoot once a year and finishes growing in early summer. However, it may produce additional shoots in the same year in response to external stimuli, called abnormal shoot growth. This study investigated the effects of open-field summer warming and drought on the abnormal shoot growth of P. densiflora seedlings. In March 2022, two factorial combinations were constructed, including two temperature treatments (control and 4°C increase) and two precipitation treatments (control and drought), with five replicates for each combination. The temperature treatment was performed for 87 days from May 14 to August 8, 2022, and the precipitation treatment was performed for 33 days from May 14 to June 15, blocking 100% of the ambient rainfall. The abnormal shoot occurrence rate and leaf unfolding stages were measured in November, and the shoot and root collar diameter growth rates were calculated by comparing the seedling height and root collar diameter measured in August (after the cessation of treatment) and October (after the end of growing period) with the initial values (i.e., May 2022). The abnormal shoot occurrence rate significantly increased under the warming treatment, showing a 410.6% increase in the warming plots (38.4%) compared to the control plots (7.5%). There was no significant difference in the shoot and root collar diameter growth rate regarding warming and drought treatments. Abnormal shoots may have been affected by high temperatures by inducing early transition to the next ontogenetic stage.

본 연구는 관수조건에 따른 지피식물의 생육특성을 파악하고 수분 스트레스 후 생육 회복력을 평가하 기 위하여 수행되었다. 지피식물로 많이 사용되는 초본류 4종을 대상으로 피복의 목적을 달성할 수 있 는 적정 식재간격을 도출하였으며, 또한 관수처리 유형에 따른 생육 및 피복률의 변화를 분석하였다. 식물마다 피복효과를 달성하기 위한 적정 식재간격에 차이가 있었다. 돌단풍은 30～35cm, 송엽국은 30～40cm간격, 꽃잔디는 40cm이상, 돌나물은 20cm미만의 식재간격이 효과적이다. 관수처리에 따른 생육특성을 분석한 결과 관수가 지속적으로 이루어지면 초장이 길지만 처리기간 동안 생육의 변화는 거의 없었다. 피복률은 관수처리와 식물에 따라 차이가 있다. 송엽국과 돌단풍은 무관수 20일 후 관수가 이루어지면 피복률도 회복되었으며, 꽃잔디는 관수가 이루어지고 나서 시간이 경과된 후에 피복률을 회복하였다. 피복이 전체적으로 이루어진 이후에는 토양 수분부족에 의한 피복률의 변화가 거의 없었 으나 피복 초기에 수분이 공급되지 않으면 피복에 어려움이 있다. 꽃잔디, 송엽국, 돌단풍은 일정기간 무관수가 지속되더라도 다시 관수가 이루어지면 회복이 될 수 있다. 즉 식물관리에 있어서 종 마다 차이 는 있으나 관수관리가 중요하며, 일정기간 무관수 후 관수가 이루어지면 생육이 회복될 수 있다.

The Republic of Korea reclaimed land to increase its food self-sufficiency rate, but the yield was reduced due to abnormal climate. In this study, it was hypothesized that rapid and continuous monitoring technology could help improve yield. Using the vegetation index (VI) analysis, the drought stress index was calculated and the drought stress for corn grown in Hwaong, Saemangeum, and Yeongsan River reclaimed tidal land was predicted according to drying treatment. The vegetation index of corn did not decrease during the last 20 days of irrigation when soil moisture rapidly decreased, but decreased rapidly during the 20 days after irrigation. The reduction rate of the vegetation index according to the drying treatment was in the order of Saemangeum>Yeongsan River>Hwaong reclaimed tidal land, and normalized difference vegetation index (NDVI) decreased by approximately 50% in all reclaimed tidal lands, confirming that drought stress occurred due to the decrease in moisture content of the leaves. In addition, structure pigment chlorophyll index (SIPI) and photochemical reflectance index (PRI), which are calculated based on changes in light use efficiency and carotenoids, were reduced; drought stress caused a decrease in light use efficiency and an increase in carotenoid content. Therefore, vegetation index analysis was confirmed to be effective in evaluating and predicting drought stress in corn growing on reclaimed tidal land corn.

본 연구에서는 밭가뭄을 선제적으로 대응하기 위한 자료를 구축하고자 충청도 지역 대표 밭작물의 시공간적 부족수량을 파악하였다. 고추 등 5개 대표 밭작물과 충청도의 5개 지역을 선정하였고, 작물별 필요수량과 지역별 공급량을 고려하여 부족수량을 산정하였다. 한국농어촌공사의 HOMWRS (Hydrological Operation Model for Water Resource System) 모형을 이용한 작물의 필요수량과 공공관정과 민간관정의 채수량, 상수도 공급량을 조사하여 지역별 용수공급량을 평가하였다. 2014년부터 2018년까지 5년간의 월별 평균 필요수량과 공급량의 차이에 따른 부족수량 을 기준으로 가뭄수준과 시기를 분석하였다. 공공관정, 민간관정, 상수도 공급량 순으로 필요수량과 차이를 산정한 결과 예산(사과)의 6월 부족수량이 가장 높았고, 괴산(콩)의 8월이 두번째로 나타났다. 그 외 지역에서는 관정과 상수도 공급량을 모두 고려할 경우 대체적으로 안정적인 공급이 가능하였으나, 청양(고추)에서 2018년 7월과 8월에 공급량이 부족한 것으로 나타났다. 시공간적 가뭄수준 분석 결과는 공간적 우선순위 결정과 시기별 공급량 확보를 위한 기초자료로 활용될 것으로 판단된다.

To understand antioxidant enzyme response of two contrasting Arundinella hirta ecotypes to drought stress, drought-tolerant Youngduk and drought-sensitive Jinju-1, were comparatively analyzed changes in the enzymatic activities of peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR). Two ecotypes, drought-tolerant Youngduk and drought-sensitive Jinju-1 were subjected to drought stress by withholding water for 12 days. ROS accumulation level and electrolytic leakage were significantly increased in both A. hirta ecotypes by drought stress treatment but less in Youngduk than Jinju-1. The RWC significantly decreased in both the drought stress-treated ecotypes as compared to control, but less in Youngduk than Jinju-1. Soluble sugar and protein content were increased more in drought stress-treated Youngduk as compared to Jinju-1. The activities of antioxidant enzymes such as SOD, CAT, POD, APX, and GR increased significantly in both the drought stress-treated ecotypes Youngduk and Jinju-1 as compared to control. The increase in antioxidant enzyme activity level was more prominent in drought stress-treated Youngduk as compared to Jinju-1. Taken together, these results suggest that Youngduk was more tolerant to drought stress than Jinju-1, and seem to indicate that tolerance of A. hirta to drought stress is associated with increased activity of antioxidant enzymes.

최근 기후변화로 가뭄, 홍수 등 재해의 빈도와 강도가 높아지고 있다. 이러한 재해의 피해를 줄이기 위해서는 시공간적 현황 파악을 통한 대비가 필요하다. 본 연구에서는 가뭄의 피해를 최소화하고자 지역별 밭작물의 필요수량과 공급량을 고려하여 밭가뭄 지역 등급화 실시하였고, 월별 비교를 통해 가뭄 취약 시기를 파악하였다. 전국 148개 지역 중 안전지역(Ⅰ), 안전지역(Ⅱ), 우려지역, 상습지역으로 구분한 25개 지역을 선정하였으며, 이 지역의 월별 필요수량 대비 공급량 분석을 하였다. 필요수량 산정의 재배작물은 콩으로 선정하였으며, 공급량은 공공관정, 민간관정, 상수도 자료를 분석하였다. 필요수량 대비 공급량이 봄철은 안전지역(Ⅰ), 안전지역(Ⅱ), 우려지역, 상습지역에서 각 1,281.5%, 667.6%, 729.5%, 316.3%, 가을철에는 각 436.0%, 212.8%, 213.9%, 105.3%로 공급이 충분할 것으로 분석되었으나 여름철에는 각 82.4%, 40.6%, 42.6%, 20.0%로 용수공급 이 부족한 것으로 분석되었다. 콩의 재배 기간인 5~9월에 관정(공공+민간)으로의 공급량은 대부분 지역에서 부족한 것으로 분석되었다. 이러한 분석을 통해 용수 부족이 발생하는 재배기간 동안 용수확보 방안이 필요하다.

The plant-specific NAC transcription factors control various biological processes, including plant development and stress responses. We have isolated an ANAC032 gene, one of the NAC transcription factor family, which was highly activated by multi-abiotic stresses, including high salt and drought in Arabidopsis. Here, we generated transgenic plants constitutively expressing ANAC032 and its knockout to identify the functional roles of ANAC032 in Arabidopsis under abiotic stress responses. The ANAC032-overexpressing plants showed enhanced tolerance to salinity and drought stresses. The anac032 knockout mutants were observed no significant changes under the high salt and drought conditions. We also monitored the expression of high salt and drought stress-responsive genes in the ANAC032 transgenic plants and anac032 mutant. The ANAC032 overexpression upregulated the expression of stress-responsive genes, RD29A and ERD10, under the stresses. Thus, our data identify that transcription factor ANAC032 plays as an enhancer for salinity and drought tolerance through the upregulation of stress-responsive genes and provides useful genetic traits for generating multi-abiotic stress-tolerant forage crops.

살리실산은 식물의 생장 및 발달, 항산화 방어기작, 광합성 작용 그리고 생물적 및 비생물적 스트레스 조건에서 다양한 생리적 기능을 조절하는 물질로 알려져 있다. 본 연구에서는 고온･건조 스트레스 조건에서 살리실산 경엽처리가 고추의 생육, 광합성 특성 및 항산화효소 활성에 미치는 영향을 구명 하고자 하였다. 광합성 특성 측정결과 광합성 속도, 기공전도 도 및 증산 속도가 증가하였고, 3회차 처리에서 가장 높았다. 세포내 MDA와 H2O2 함량은 살리실산 3회차 처리에서 현저 하게 감소하는 경향을 보였다. APX, CAT, POD 및 SOD 활 성이 현저하게 증가하였으며, 무처리 대비 최대 247, 318, 55 및 54% 증가하였다. 고추의 생육 특성은 무처리구와 유의한 차이를 보이지 않았으나, 상품 수량은 15% 정도 증가하였다. 이러한 결과들을 종합해 볼 때, 살리실산의 경엽처리는 고추 의 광합성 특성과 항산화효소 활성을 증진시켜 고온･건조 스트 레스에 의한 피해 경감에 긍정적 효과를 유발함을 확인하였다

Drought stress is a condition that occurs frequently in the field, it reduces of the agricultural yield of field crops. The aim of the study was to screen drought-adapted genotype of Italian rye grass. The experiments were conducted between the two Italian ryegrass (Lolium multiflorum L.) cultivars viz. Hwasan (H) and Kowinearly (KE). The plants were exposed to drought for 14 days. The results suggest that the morphological traits and biomass yield of KE significantly affected by drought stress-induced oxidative stress as the hydrogen peroxide (H2O2) level was induced, while these parameters were unchanged or less affected in H. Furthermore, the cultivar H showed better adaptation by maintaining several physiological parameter including photosystem-II (Fv/Fm), water use efficiency (WUE) and relative water content (RWC%) level in response to drought stress. These results indicate that the cultivar H shows improved drought tolerance by generic variation, improving photosynthetic efficiency and reducing oxidative stress damages under drought stress. These findings can be useful to the breeder and farmer for improving drought tolerance in Italian rye grass through breeding programs.

The objective of this study was to determine effects of phosphorus on lignification and carbohydrate metabolism in Kentucky bluegrass under drought stress. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (PO4 3-; P) or potassium phosphonate (PO3 3-; PA) in drought-stressed plants. Drought had significant negative effects on plant growth, as revealed by reduced biomass of shoot. Drought-induced increase of lignin content was concomitant with the increase of phenylalanine ammonia-lyase (PAL). Soluble sugar content was highly increased but fructan content was largely decreased by drought stress. However, the application of phosphorus was efficient to ameliorate the adverse effects of drought. PA application improved reduced shoot growth and relative water content, and inhibited lignification synthesis with a reduction of PAL activity. P or PA application maintained soluble sugar and fructan content at similar levels to controls under drought stress. These results indicate that phosphorus application may mitigate the drought stress by inhibiting the lignification and promoting the fructan assimilation.

The objective of this study was to determine phosphorus effects on drought stress-induced oxidative stress in Kentucky bluegrass. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (P) or potassium phosphonate (PA). Application of phosphorus was efficient to ameliorate the adverse effects of drought. Osmotic potential, total chlorophyll and carotenoid content were significantly decreased by drought stress, but was relieved by P or PA application. Superoxide (O2 •−) concentration was significantly increased more than 14-fold under drought-stressed plants, was accompanied with increase of hydrogen peroxide (H2O2) and lipid peroxidation (MDA). However, malondialdehyde (MDA) was much less in P or PA applied plants under drought stress condition. Activities of catalase (CAT), ascorbate peroxidase (APX) and guaiacol-peroxidase (GPX) were largely increased by drought stress and its increase rate was much higher in P or PA applied plants except APX. These results indicate that drought stress-induced oxidative stress is alleviated by P or PA application due to the increase of activities of antioxidant enzymes.