• 한국환경과학회지
• /
• 제2권1호
• /
• pp.37-48
• /
• 1993

Effect of plant hormones on the leaf senescence of mung bean (Phseoln radiatus) was investigated by measuring the changes of reducing sugar contents and invertase isozyme activities in detached leaves treated with NAA, $GA_3$ or BA. During dark-induced senescence, reducing sugar contents in the detached leaves increased temporarily at 4 6, thereafter decreased rapidly and reached minimum values within 7-14 6. The pattern of soluble acid invertase activity in the senescing leaves kept in the dark was similar to that of reducing sugar accumulation, whereas the activities of alkaline and extracellular invertases were not significantly changed during leaf senescence. Therefore, these results suggest that soluble acid invertase, but not alkaline and extracellular invertases, induces the accumulation of reducing sugar during leaf senescence of Rung bean plants. Exogenous NAA application had little or no effect In the increase of soluble acid invertase activity during dark-induced senescence compared to the control. However, exogenous applications of $GA_3$ and BA led to the increase of soluble acid invertase activity in the senescing leaves. Particularly, BA application was very effective In enhancing the activity of soluble acid invertase as well as in delaying chlorophyll breakdown during dark-induced senescence. These results suggest, therefore, that BA regulates the activity of soluble acid invertase, which leads to the accumulation of reducing sugar, and the stability of photosynthetic apparatus to delay leaf senescence.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2023년도 춘계학술대회
• /
• pp.157-157
• /
• 2023

Pre-harvest sprouting (PHS) in rice (Oryza sativa L.) is one of the main problems associated with seed dormancy. PHS causes yield loss and reduction of grain quality under unpredictable humid conditions at the ripening stage, thus affecting the economic value of the rice crop. To resolve this issue, it is important to understand the molecular mechanism underlying seed dormancy in rice. Recent studies have shown that seed dormancy is affected by a large number of genes associated with plant hormones. However, the effect of heat stress on seed dormancy and plant hormones is not well understood. In this study, we compared the PHS rate as well as the transcriptome and small RNAome of the seed embryo and endosperm of two different accessions of rice, PHS-susceptible rice (low dormancy) and PHS-resistant rice (high dormancy) under three different maturation stages. We identified and verified the candidate genes associated with seed dormancy and heat stress-related responses in rice using quantitative real-time PCR. We newly discovered hormone-related genes, heat shock protein-related genes, and miRNAs potentially involved in PHS. These findings provide a foundation for understanding the dynamics of transcriptome and small RNAome of hormone- and heat stress-related genes, which affect PHS during seed maturation.

• 생명과학회지
• /
• 제15권1호
• /
• pp.112-117
• /
• 2005

하천변에 사는 식물들은 침수 저항성을 갖추고 있는데 그중 Ranunculus속이나 Rumex속에 속하는 일부 반수생 식물들에서 볼 수 있는 것처럼, 엽병이 급격한 생장을 일으켜 잎이 수표면에 이르게 함으로써 호흡할 수 있는 조건을 확보하는 현상은 식물체내에 축적된 에틸렌에 의하여 매개되는 현상이다. 침수 조건에서는 식물 조직 내에 에틸렌이 축적되며, 축적된 에틸렌은 옥신 등 다른 식물호르몬에 대한 조직의 감수성을 증가시켜 생장을 촉진한다. 증가된 생장으로 잎이 수표면에 이르게 되면 다시 공기를 접촉하여 호흡할 수 있게 되고, 식물체내에 축적되었던 에틸렌은 대기 중으로 확산하여 나가게 되므로 체내 에틸렌 농도가 감소하여 생장률이 침수 이전 수준으로 되돌아간다. 에틸렌에 의한 옥신의 감수성 증가는 선량 반응 곡선에 비추어 수용체의 친화도 증가가 수반되는 것으로 생각되는데, 아직 옥신 수용체가 밝혀지지 않아 분자생물학적 기작은 연구되어야 할 과제로 남아있다. 최근 옥신 수용체 발견의 가능성이 높아지고 있으며, 따라서 에틸렌에 의한 옥신 수용체의 옥신에 대한 감수성 조절기작을 탐구할 수 있는 길이 열릴 것으로 기대된다.

• Molecules and Cells
• /
• 제27권6호
• /
• pp.615-620
• /
• 2009

The plant shoot meristem maintains a group of stem cells that remain active throughout the plant life. They continuously generate new cells that are then recruited for organ initiation in the peripheral zone. Stem cell proliferation and daughter cell differentiation has to be integrated with overall growth and development of the diverse functional domains within the shoot apex. Several studies have revealed extensive communication between these domains. The signaling mechanisms employed comprise diffusible peptides, directional transport of plant hormones, but also complex interactions between transcription factors, that together establish a panoply of regulatory inputs that fine-tune stem cell behavior in the shoot meristem.

• The Plant Pathology Journal
• /
• 제26권2호
• /
• pp.101-109
• /
• 2010

Protein phosphorylation is one of the major mechanisms for controlling many cellular processes in all living organisms. Mitogen-activated protein kinase (MAPK) cascades are known to transducer extracellular stimuli to several cellular processes, including cell division, differentiation as well as responses to various stresses. In plants, several studies have revealed that MAPK cascade pathways play an important role in responses against biotic and abiotic stresses, including wounding, pathogen infection, temperature, drought, salinity and plant hormones. It is also known that MAPK cascades-mediated signaling is an essential process in the resistance step to pathogens by regulating the activity of transcription factors. Here, the insights into the functions of MAPK cascade pathways in plant defense response signaling from Arabidopsis, tobacco and rice are described.

• Molecules and Cells
• /
• 제41권8호
• /
• pp.724-732
• /
• 2018

Plant defence responses to various biotic stresses via systemic acquired resistance (SAR) are induced by avirulent pathogens and chemical compounds, including certain plant hormones in volatile form, such as methyl salicylate and methyl jasmonate. SAR refers to the observation that, when a local part of a plant is exposed to elicitors, the entire plant exhibits a resistance response. In the natural environment, plants are continuously exposed to avirulent pathogens that induce SAR and volatile emissions affecting neighbouring plants as well as the plant itself. However, the underlying mechanism has not been intensively studied. In this study, we evaluated whether plants "memorise" the previous activation of plant immunity when exposed repeatedly to plant defensive volatiles such as methyl salicylate and methyl jasmonate. We hypothesised that stronger SAR responses would occur in plants treated with repeated applications of the volatile plant defence compound MeSA than in those exposed to a single or no treatment. Nicotiana benthamiana seedlings subjected to repeated applications of MeSA exhibited greater protection against Pseudomonas syringae pv. tabaci and Pectobacterium carotovorum subsp. carotovorum than the control. The increase in SAR capacity in response to repeated MeSA treatment was confirmed by analysing the defence priming of the expression of N. benthamiana Pathogenesis-Related 1a (NbPR1a) and NbPR2 by quantitative reverse-transcription PCR compared with the control. We propose the concept of plant memory of plant defence volatiles and suggest that SAR is strengthened by the repeated perception of volatile compounds in plants.

• Journal of Plant Biotechnology
• /
• 제42권4호
• /
• pp.277-283
• /
• 2015

Plant genome analyses, including Arabidopsis thaliana showed a large gene family of plant receptor kinases with various extracellular ligand-binding domain. Now intensively studies to understand physiological and cellular functions for higher plant receptor kinases in diverse and complex biological processes including plant growth, development, ligands perception including steroid hormone and plant-microbe interactions. Brassinosteroids (BRs) as a one of well know steroid hormone are plant growth hormones that control biomass accumulation and also tolerance to many biotic and abiotic stress conditions and hence are of relevance to agriculture. BRI1 receptor kinase, which is localized in plasma membrane in the cell sense BRs and it bind to a receptor protein known as BRASSINOSTEROID INSENSITIVE 1 (BRI1). Recently, we reported that BRI1 and its co-receptor, BRI1-ASSOCIATED KINASE (BAK1) autophosphorylated on tyrosine residue (s) in vitro and in vivo and thus are dual-specificity kinases. Other plant receptor kinases are also phosphorylated on tyrosine residue (s). Post-translational modifications (PTMs) can be studied by altering the residue modified by directed mutagenesis to mimic the modified state or to prevent the modification. These approaches are useful to not only characterize the regulatory role of a given modification, but may also provide opportunities for plant improvement.

• 한국잡초학회지
• /
• 제8권2호
• /
• pp.176-181
• /
• 1988

본(本) 시험(試驗)은 수도(水稻)(품종(品種): 일본청(日本晴)) 엽편(葉片)을 이용(利用)한 산소전극법(酸素電極法)의 광합성속도(光合成速度)와 엽록소(葉綠素) 보유능(保有能)에 미치는 식물(植物)호르몬의 작용(作用)을 구명(究明)코자 수행(遂行)하였으며, 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 산소전극법(酸素電極法)에 의(依)한 수도(水稻) 광합성속도(光合成速度)에 미치는 식물(植物)호르몬의 효과(效果) 가. 광합성속도(光合成速度)에 미치는 IAA의 경과일수별효과(經過日數別效果)는 20 ppm 처리(處理)에서 약간 조해(阻害)되었으나 저농도(低濃度)에서는 무처리(無處理)와 유사(類似)하였다. 나. BA 0.2, 2, 20 ppm의 경과일수별(經過日數別) 효과(效果)는 BA 농도(濃度)가 높을수록 현저(顯著)하게 고양(高揚)되었다. 마. $GA_3$는 고농도(高濃度)인 20ppm 처리(處理)에서 조해작용(阻害作用)이 보였다. 라. ABA는 모든 처리농도(處理濃度)에서 조해작용(阻害作用)이 보였고, 농도(濃度)가 높을수록 더욱 조해(阻害)되었다. 2. 식물(植物)호르몬이 수도(水稻)의 엽록소(葉綠素) 보유능(保有能)에 미치는 효과(效果) 가. IAA, BA, $GA_3$는 농도(濃度)가 높을수록 엽록소(葉綠素) 보유능(保有能)이 높았다. 나. ABA는 0.2, 2, 20 ppm 전처리(全處理)에서 현저(顯著)한 엽록소(葉綠素) 감쇠(減衰)가 보였다.

• 한국수산과학회지
• /
• 제18권3호
• /
• pp.271-277
• /
• 1985

외톨개모자반의 재생장에 미치는 식물호르몬의 효과를 조사하기 위하여 제1측지에서는 생식기탁이 형성중인 정단부위와 정단에서 30mm 떨어진 하위부, 그리고 제 2측지에서는 정단에 서 5 mm하위부인 3부분에서 절편을 취하여, PESI를 기본배지로 하고 2,4-D, kinetine, NAA 그리고 IAA의 mole 농도별 용액에서 60 일간 배양하였다. 1. 식물호르몬의 재생장에 미치는 유효농도는 $10^{-5}M{\sim}10^{-8}M$이며 조해농도는 $10^{-3}M{\sim}10^{-4}M$이었다. 2. 제1측지의 재생장효능은 kinetine $10^{-8}M$, 2,4-D, $10^{-5}M$, NAA $10^{-6}M$ 그리고 IAA $10^{-6}M$ 순이었다. 3. 제2측지의 재생장효능은 NAA $10^{-6}M$, kinetine $10^{-8}M$, IAA $10^{-6}M$ 그리고 2,4-D $10^{-5}M$ 순이었다. 4. 제1측지와 제2측지의 순재생률에서 최대치는 각각 kinetine $10^{-6}M(157.3\%)$과 NAA $10^{-6}M(447.2\%)$이었고, 대조에서도 $124.1\%$와 $228.9\%$로 재생효능은 제2측지가 높았다. 5. 제2측지 절편에서 재생분지한 돌기는 모두 생식기탁으로 분화하였다. 6. 생식기탁 절편은 배양 $20{\sim}30$일 사이에 재생분지한 소지가 전부 생식기탁으로 성장하여 생란기를 형성하였고 40 일 후부터는 방란후 소실하였다.

• 생명과학회지
• /
• 제8권6호
• /
• pp.623-626
• /
• 1998

포인세티아식물체의 줄기조직을 이용한 재분화조건을 확립하였다. MS배지에 종류 및 농도별 식물성장 조절제를 첨가하여 포인세티아의 잎, 줄기, 엽병조직으로부터의 배구조의 발생을 조사하였다. 잎과 엽병조직에서는 callus의 형성은 실험조건에서 매우 활발하였으나 배구조로의 발달은 전혀 이루어지지 않았다. 줄기조직의 경우에서는 1.5 mg/L의 BA가 첨가되는 경우 6-8주 정도의 경과 후 엽초의 발생이 관찰되었다. 이들을 식물생장조절제를 무첨가한 MS고체배지로 이동시 뿌리의 발달이 관찰되었다.