Optimization of acclimatization and storage conditions to improve graft take ratio and seedling quality in tomato plug production syste

Dissertation for the Degree of Doctor Optimization of Acclimatization and Storage Conditions to Improve Graft-take Ratio and Seedling Quality in Tomato Plug Production System by Vu Ngoc Thang Department of Horticulture Graduate School Kangwon National University Republic of Korea August, 2015 Supervised by Professor Kim Il Seop Optimization of Acclimatization and Storage Conditions to Improve Graft-take Ratio and Seedling Quality in Tomato Plug Production System A DISSERTATION Submitted to the Graduate School of Kangwon National University In Partial Fulfillment of the Requirements for the Degree of DOCTOR OF AGRICULTURE By Vu Ngoc Thang Department of Horticulture August, 2015 Approved by Committee of the Graduate School of Kangwon National University in Partial Fulfillment of the Requirement for Degree of Doctor of Agriculture Vu Ngoc Thang August, 2015 Dissertation Committee: Kim Jong Hwa (Chairman of committee) (Signature) Kim Il Seop (Committeeman) (Signature) Kang Ho Min (Committeeman) (Signature) Kang Won Hee (Committeeman) (Signature) Lee Yong Beom (Committeeman) (Signature) Optimization of Acclimatization and Storage Conditions to Improve Graft-take Ratio and Seedling Quality in Tomato Plug Production System Vu Ngoc Thang Department of Horticulture Graduate School, Kangwon National University Abstract Although many grafting methods and techniques for environmental control during grafting process are widely recognized, many other factors must be carefully considered to ensure successful grafting process with this technology In order to enhance graft-take ratio and quality of tomato seedlings, control environmental conditions were studied in second chapter In this chapter, control temperature, humidity was examined in first study The higher graft-take ratios (84.0-87.4%) were showed at 23oC compared to 20oC and 26oC in all rootstock cultivars Grafttake ratios decreased and percentage of infected plants increased at high temperature The graft-take ratios increased with increasing relative humidity in all temperature levels However, increasing relative humidity significantly increased percentage of infected plants The graft-take ratio increased with increasing period of 90% relative humidity, but it decreased with continued increasing 90% relative humidity for 10 days The high relative humidity (90%) for first or days and afterwards reduced low relative humidity (70%) at 23oC condition during healing and acclimatization promoted the graft-take and quality of grafted tomato seedlings From above optimal temperature and humidity, effect of water content in substrate, i grafting position and different cultivars on the graft-take ratio and quality of tomato seedlings were investigated The graft-take ratio and seedling quality were improved by control of water content in the substrate The maximum graft-take ratio (100%) with the highest compactness value was observed in seedlings which were grafted by scion mid water content and rootstock high water content in the substrate There was no significant difference in graft-take ratio between two grafting positions but grafting position effected on growth characteristics of grafted tomato seedlings There was significant different among scion cultivars but not significant different among rootstock cultivars with graft-take ratio In addition, influence of short-term irradiation by light quality on the graft-take ratio and quality of tomato seedlings was also investigated When short-term irradiation was applied before grafting, the graft-take ratios (27.8-66.7%) were considerably low in all light treatments as compared with natural light (96.7%) The graft-take ratio of red LED was not statically different with WFL treatment, but higher than far-red and blue LED treatments The lowest graft-take ratio (27.8%) was observed in darkness treatment Changing light intensity before grafting was the cause of reduced graft-take ratios in this study There was no significant difference among natural light, WFL, and red LED treatments in growth parameters, except for leaf chlorophyll level, leaf width, and fresh weight of root, but decreased in seedlings treated with far-red LED, blue LED, and darkness Graft-take ratios (68.5-100.0%) were enhanced when short-term irradiation was applied after grafting The maximum (100%) graft-take ratio was recorded in red LED treatment, but was not statistically different with the WFL treatment The lowest graft-take ratio was also observed in the darkness treatment Plant growth responses to red LED were also similar with those to WFL after grafting However, when short-term irradiation was applied after grafting, the lowest values of plant growth were observed in far-red LED treatment The plant growth parameters were similar in seedlings treated with darkness and blue LED, but lower than red LED and WFL treatments The root ii morphology was improved in seedlings treated with red LED after grafting by increasing total root surface, total root length, and number of root tips Seedling quality increased at 35 days after transplanting in the red LED treatment by increased plant growth parameters, especially compactness and root morphology, as compared with other treatments In order to confirm effect of red LED on grafttake ratio and seedling quality, red LED and no light (darkness) were examined on three rootstock cultivars The result showed that graft-take ratios in red LED were higher than those in no light treatment Significant variation on graft-take ratio of rootstock cultivars was observed in no light treatment but there was not significant variation in red LED treatment Red LED treatment also reduced the percentage of infected plants Seedling quality in red LED was better than that in no light treatment by improving growth parameters Tomato seedling quality is highly valued in Korea vegetable production Ideally, tomato seedlings are transplanted when they reach the correct size, but seedlings are often ready before grower can transplant them Therefore, growth must be slowed or delayed Low temperature storage can be used to stop or suppress the growth and development of tomato seedlings while preserving its quality and not adversely affecting future growth Therefore, effect of low storage temperature on growth and quality of tomato seedlings was investigated Inhibition of seedling elongation was observed in all low storage temperature levels However, 4oC temperature was not suitable for long-term storage of tomato seedlings Plant height and number of leaves decreased with decreasing storage temperature Leaf chlorophyll values decreased with increasing storage duration However, above 10 days storage duration leaf chlorophyll value of seedlings at nature condition was lower than that at 13oC temperature level, but it was higher than that at 10oC and 7oC temperature level Chilling injury and curly leaf were observed in seedlings at 10, 7oC temperature after 10 or 20 days storage, but they were not observed in seedlings at 13oC temperature The time of expanding leaf and chilling injury index iii of seedlings at and 10oC temperatures increased with increasing storage duration and decreasing storage temperature The delay flowering was observed in all low temperature treatments Delay flowering time increased with increasing storage duration and decreasing storage temperature After 10 or 20 days storage, growth parameters of tomato seedlings decreased significantly with decreasing storage temperature, except leaf chlorophyll value, specific leaf area and average root diameter However, there were not statistically different in seedlings at 10 and 7oC with growth parameter except plant height, leaf area and specific leaf area Although growth parameters decreased significantly with decreasing storage temperature, but after 10 days storage the compactness of seedlings at 13, 10 and 7oC were similar to that at nature condition However, after 20 days storage the compactness of seedlings decreased significantly in low storage temperature In order to improve seedling quality of tomato in long-term storage duration at low temperature, effect of silicon and ABA on growth and abiotic stresses and examination of silicon and ABA’s ability to maintain the seedling quality of tomato at low storage temperature were investigated in the fourth chapter Although silicon (Si) has not been listed among the essential elements for plant growth, however, the beneficial role of silicon in stimulating the growth and development of many plant species has been generally recognized Silicon is also known to effectively mitigate various abiotic stresses Based on this study, silicon stimulated the growth and development of tomato seedlings by increasing growth parameters, root morphology Transpiration rate decreased and stomatal diffusive resistance increased with increasing silicon concentrations to 32 mM Silicon could migrate to reduce chilling injury index during low temperature by reducing damage of leaf area The plant hormone abscisic acid (ABA) is an important regulator in many aspects of plant growth and development, as well as stress resistance Therefore, in the other studies, foliar application of ABA affected in reducing growth characteristics of tomato seedlings However, ABA enhanced cold tolerance in iv tomato seedlings by reducing relative ion leakage and chilling injury index in low temperature In addition, ABA also enhanced drought tolerance in tomato seedlings by decreasing transpiration rate in the leaf therefore ABA delaying the starting time of wilting point in drought condition Although lower transpiration rate and higher stomatal diffusive resistance in 50 mg•L-1 treatment compared with control but transpiration rate and stomatal diffusive resistance in 50 mg•L-1 of ABA treatment were much higher and lower than those of 100 mg•L-1 of ABA treatment Therefore in the control treatment the start time of wilting point was observed on the third day, but in 50 and 100 mg•L-1 of ABA treatments the start time of wilting point were observed on the fifth and seventh day after without irrigation, respectively Based on above results, 16 mM of silicon and 100 mg•L-1 of ABA were applied for tomato seedlings before storage The result shown that during storage duration plant height of tomato seedlings increased in silicon but decreased in ABA treatment Number of leaf was similar between non-treatment and silicon treatment in the same storage duration, but they decreased significantly in ABA treatment The leaf chlorophyll content of seedlings at 7oC was lower than those at 10oC in all treatments during storage duration, but leaf chlorophyll content of seedlings in ABA treatment was higher than that in silicon and non-treatment Silicon and ABA improved seedlings quality in low temperature by reducing damage of leaf area However, chilling injury index of seedlings in ABA treatment was lower than that in silicon treatment Silicon and ABA improved number of flowers at second, third and fourth cluster and also improve number of fruits at second and third cluster in all two levels of temperature However, number flowers and fruits of plants treated with ABA were greater than those in silicon treatment Keywords: Environment, grafting, seedling quality, storage condition, tomato v Acknowledgments First and foremost, I wish to express my sincere gratitude to Professor Kim Il Seop of College of Agriculture and Life Sciences - Kangwon National University He, as my academic advisor, has continuously provided the intellectual stimulation required to develop the skill of scientific approach I am also indebted to him for the guidance and financial support throughout the period of my study I would like to express my sincere appreciation to my thesis committee Prof Kim Jong Hwa, Prof Kang Ho Min, Prof Kang Won Hee of Kangwon National University, and Prof Lee Yong Beom of University of Seoul for their valuable suggestions and helpful comments They encouraged and discussed many problems with me My sincere thank to Prof Jeong Cheon Soon, and Prof Park Sung Min of Kangwon National University for offering their kind and valuable advice I would like to thank to all leaders of Vietnam National University of Agriculture for providing me study leave The past three years working in Kangwon National University, I always obtained comments and helps from a lot of Professors, Doctors, Researchers, and other lab members in there Although I can’t list all of their names but I would like to thank for their advices in my PhD study Finally, I thank my wife and daughter who have given me generous support and understanding in every part of my life And I would also like to express the deepest gratitude to my father, mother and sister for all of the visible and invisible supports they have given to me in long-time Author Vu Ngoc Thang vi Content Abstract …………………………………………………………………… iv Acknowledgments ………………………………………………………… ix Content ……………………………………………………………………… x List of Tables ……………………………………………………………… xiv List of Figures ……………………………………………………………… xviii List of Abbreviations ……………………………………………………… xxi Chapter I General Introduction ………………………………………… Chapter II Improving the Graft-take Ratio and Quality of Grafted Tomato Seedlings by Controlling Environmental Condition 2.1 Abstract ………………………………………………… …… 2.2 Introduction ……………………………………… 2.3 Materials and methods …………………………………… … 12 2.3.1 Plant material and growing scions and rootstocks…… 12 2.3.2 Grafting method, healing and acclimatization process … 12 2.3.3 Temperature and humidity treatments …………………… 13 2.3.4 Water content in substrate, grafting position and different cultivars ……………………………….……… …………… 14 2.3.5 Light quality treatment……………………………………… 15 2.3.6 Data collection and analysis ……………… ………… 16 2.4 Results …………………………………………… ………… 18 2.4.1 Enhanced graft-take ratio and quality of grafted tomato seedlings by controlling temperature and humidity conditions 18 2.4.1.1 Effect of temperature on graft-take ratio and infected plants in four rootstock cultivars……………………………… … 2.4.1.2 Effect of humidity on graft-take ratio and infected vii 18 2006 Beneficial effects of silicon in wheat (Triticum aestivum L.) under salinity stress Pak J Bot 38:1715-1722 Munns, R and G.R Cramer 1996 Is coordination of leaf and root growth mediated by abscisic acid? Opinion Plant and Soil 185:33-49 Murchie, E.H and P Horton 1997 Acclimation of photosynthesis to irradiance and spectral quality in British plant species: chlorophyll content, photosynthetic capacity and habitat preference Plant, Cell & Environment 22:438-448 Nahar, K., S.M Ullah, and R Gretzmacher 2011 Influence of soil moisture stress on height, dry matter and yield of seven tomato cultivars Canadian J Scientific and Industrial Res 2:160-163 Nahar, K., S.M Ullah, and R Gretzmacher 2011 Influence of soil moisture stress on height, dry matter and yield of seven tomato cultivars Canadian J Scientific and Industrial Res 2:160-163 Neff, M.M., C Fankhauser, and J Chory 2000 Light: an indicator of time and place Genes & Dev 14:257-271 Nicola, S 1998 Understanding root systems to improve seedling quality HortTechnol 8:544-549 Nishiura, Y 1999 Primary study on the development of acclimating system for grafted seedlings using the alive plants information as a feedback control signal Proceeding of 1999 JSAM conference on agricultural engineering 489-490 Japan: Saga Nishina, H., K Yoshida, N Masui, and Y Hashimoto 1996 Storage of tomato seedling plant plugs under faint irradiation and low temperature Acta Horti 440:268-273 Nobuoka, T., M Oda, and H Sasaki 1996 Effect of relative humidity, light intensity and leaf temperature of tomato J Jpn Soc Hort Sci 64:859-865 145 Nobuoka, T., T Nishimoto, and K Toi 2005 Wind and light promote graft-take and growth of grafted tomato seedlings J Jpn Soc Hort Sci 74:170-175 Oda, M., K Tsuji, and H Sasaki 1993 Effect of hypocotyls morphology on survival rate and growth of cucumber seedlings grafted on Cucurbitaspp J Jpn Soc Hortic Sci 26:259-263 Oda, M., K Tsuji, K Ichmura, and H Sasaki 1994 Factors affecting the survival of cucumber plants grafted on pumpkin plants by horizontal grafting at the hypocotyl level Bul Natl Res Inst Veg Ornamental Plants, Tea 9:51-60 Oda, M 1995 New grafting methods for fruit-bearing vegetables in Japan JARQ 29:187-194 Oda, M 1999 Grafting of vegetables to improve greenhouse production Food and Fertilizer Technology Centre Extension Bulletin 480:1-11 Oda, M., M Maruyama, and G Mori 2005 Water transfer at graft union of tomato plants grafted onto Solanum rootstocks J Jpn Soc Hort Sci 74:458-463 Oda, M 2007 Raising of vigorous and valuable seedlings Regul Plant Grow Develop 42:176-182 Ogata, T., Y Kabashima, S Shiozaki, and S Horiuchi 2005 Regeneration of the vascular bundle at the graft interface in auto-and heterografts with juvenile nucellar seedlings of satsuma mandarin, yuzu and trifoliate orange J Jpn Soc Hort Sci 74:214-220 Pospisilova, J., H Synkova, D Haisel, and P Batkova 2009 Effect of abscisic acid on photosynthetic parameters during ex vitro transfer of micro propagated tobacco plantlets Boil Plant 53:11-20 Ploeg, V.D and E Heuvelink 2005 Influence of sub-optimal temperature on tomato growth and yield: a review J Horti Sci Biotechnol 80:652-659 Rajasekaran, L.R and T.J Blake 1999 New plant growth regulators protect photosynthesis and enhance growth under drought of jack pine seedlings J 146 Plant Growth Regul 18:175-181 Risse, L.A., T Moffitt, and H.H Bryan 1979 Effect of storage temperature and duration on quality, survival, and yield of containerized tomato transplants Proc Fla State Hort Soc 92:198-200 Rivero, R.M., J.M Ruiz, and L Romero 2003 Role of grafting in horticultural plants under stress conditions Food Agr Environ 1:70-74 Salehi, R., A Kashi, S.G Lee, Y.C Hou, J.M Lee, M Babalar, and M Delshas 2009 Assessing the survival and growth performance of Iranian melons to grafting onto Cucurbita rootstocks Korean J Hort Sci Technol 27:1-6 Savvas, D., G Manos, A Kotsiras, and S Souva-iotis 2002 Effects of silicon and nutrient-induced salinity on yield, flower quality and nutrient uptake of gerbera grown in a closed hydroponic system J Appl Bot 76:153-158 Seebold, K.W., T.A Kucharek, L.E Datnoff, F.J Correa-Victoria, and M.A Marchetti 2001 The influence of silicon on components of resistance to blast in susceptible, partially resistance, and resistant cultivars of rice Phytopathology 91:63-69 Seiler, J.R and J.D Johnson 1988 Physiological and morphological responses of three half-sib families of loblolly pine to water-stress conditioning For Sci 34:487-495 Singh, K., R Singh, J.P Singh, Y Singh, and K.K Singh 2006 Effect of level and time of silicon application on growth, yield and its uptake by rice (Oryza sativa) Indian J Agric Sci 76:410-413 Sharp, R.E., Y Wu, G.S Voetberg, I.N Saab, and M.E Lenoble 1994 Confirmation that abscisic acid accumulation is required for maize primary root elongation at low water potentials J Expt Bot 45:1743-1751 Shibata, K., T Kubota, and S Kamisaka 1974.Isolation and chemical identification of a lettuce cotyledon factor, a synergist of the gibberellin action in inducing 147 lettuce hypocotyl elongation Plant Cell Physiol.15:191-194 Taylor, I.B., A Burbidge, and A.J Thompson 2000 Control of abscisic acid synthesis J Exp Bot 51:1563-1574 Takahashi, H., K Koshio, and Y Ota 1993 Effect of ABA application to the culture solution on the growth, water relations and temperature stress in tomato plants J Japan Soc Hort Sci 62:389-397 Tennessen, D.J., E.L Singsaas, and T.D Sharkey 1994 Light-emitting diodes as a light source for photosynthesis research Photosynthesis Res 39:85-92 Traka-Mavrona, E., M.K Soutiriou, and T Prisata 2000 Response of squash (Cucurbita spp) as rootstock for melon (Cucumis melo) Scientia Hort 83:335-362 Vu, N.T., C.H Zhang, Z.H Xu, Y.S Kim, H.M Kang, and I.S Kim 2013 Enhanced graft-take ratio and quality of grafted tomato seedlings by controlling temperature and humidity conditions Protected Hort Plant Fac 22:146-153 Vu, N.T., Y.S Kim, H.M Kang, and I S Kim 2014 Influence of short-term irradiation during pre-and post-grafting period on the graft-take ratio and quality of tomato seedlings Hort Environ Biotechnol 55:27-35 Wang, H., M Gu, J Cui, K Shi, Y Zhou, and J Yu 2009 Effects of light quality on CO2 assimilation, chlorophyll-fluorescence quenching, expression of Calvin cycle genes and carbohydrate accumulation in Cucumis sativus J Photochem Photobiol B: Biol 96:30-37 Walters, R.G., F Stephard, J.J.M Rogers, S.A Rolfe, and P Horton 2003 Identification of mutants of Arabidopsis defective in acclimation of photosynthesis to the light environment Plant Physiol 131:472-481 Waterland, N., J.J Finer, and M.L Jones.2010 Abscisic acid applications decrease stomatal conductance and delay wilting in drought-stressed chrysanthemums 148 Hort Technology 20:896-901 Watts, S., J.L Rodriguez, E Evans, and W.J Davies 1981 Root and shoot growth of plants treated with abscisic acid Ann Bot 47:595-602 Yin, H., B Yan, J Sun, P.F Jia, Z.J Zhang, X.S Yan, J Chai, Z.Z Ren, G.C Zheng, and H Liu 2012 Graft-union development: a delicate process that involves cell-cell communication between scion and stock for local auxin accumulation J Exp Bot 63:4219-4232 Yong, S.S., J.L Mun, S.L Eun, H.A Joon, H.L Jae, J.K Ha, W.P Hoo, G.U Young, D.P So, and H.C Jang 2012 Effect of LEDs (light emitting diodes) irradiation on growth and mineral absorption of lettuce (Lactuca sativa L ‘Lollo Rosa’) J Bio-Env Con 21:180-185 Yu, H and B.L Ong 2003 Effect of radiation quality on growth and photosynthesis of Acacia mangium seedlings Photosynthetica 41: 349-355 Zeevaart, J.A.D and R.A Creelman 1988 Metabolism and physiology of abscisic acid Annu Rev Plant Physiol Plant Mol Bio 39:439-473 Zhang, J.H., W.S Jia, J.C Yang, and A.M Ismail 2006 Role of ABA in integrating plant responses to drought and salt stresses Field Crops Research 97:111-119 Zhang, J., X Zhang, and J Liang 1995 Exudation rate and hydraulic conductivity of maize roots are enhanced by soil drying and abscisic acid treatment New Phytol 131:329-336 Zhao, M., X Zhao, Y Wu, and L Zhang 2007 Enhanced sensitivity to oxidative stress in an arabidopsis nitric oxide synthase mutant J Plant Physiology 164:737-745 Zhou, Q., G Pan, Z Shi, Y Meng, and Y Xie 2002 Effects of Si fertilizer application on maize yield and on quality of maize population J Maize Sci 10:81-93 149 Publications in this thesis Ngoc-Thang Vu, Cheng-Hao Zhang, Zhi-Hao Xu, Young-Shik Kim, Ho-Min Kang, and Il-Seop Kim 2013 Enhanced graft-take ratio and quality of grafted tomato seedlings by controlling temperature and humidity conditions Protected Hort Plant Fac 22(2):146-153 Ngoc-Thang Vu, Young-Shik Kim, Ho-Min Kang, and Il-Seop Kim 2014 Influence of short-term irradiation during pre- and post-grafting period on the graft-take ratio and quality of tomato seedlings Hort Environ Biotechnol 55(1):27-35 Ngoc-Thang Vu, Young-Shik Kim, Ho-Min Kang, and Il-Seop Kim 2014 Effect of red LEDs during healing and acclimatization period on the survival rate and quality of grafted tomato seedlings Protected Hort Plant Fac 23 (1):4349 Ngoc-Thang Vu, Zhi-Hao Xu, Young-Shik Kim, Ho-Min Kang, and Il-Seop Kim 2014 Effect of nursery environmental condition and different cultivars on survival rate of grafted tomato seedling Acta Horticulturae 1037(2):765770 ISSN 0567-7572 Ngoc-Thang Vu, Ki-Young Choi, and Il-Seop Kim 2014 Effect of water content in the substrate of the scion and rootstock during pre- and post-grafting on the survival rate and quality of tomato seedlings Protected Horticulture and Plant Factory.23(3):199-204 pISSN 2288-0992; eISSN 2288-100X Vu, N.T., S.H Kim, D.C Vu, and I.S Kim 2015 Effect of storage temperature and duration on growth and quality of tomato plug seedlings Journal of Agriculture, Life and Environmental Sciences 27(1):30-38 ISSN 2233-8322 150 Ngoc-Thang Vu, Ho-Min Kang, Young-Shik Kim, Ki-Young Choi and Il-Seop Kim 2015 Growth, physiology and abiotic stress response to abscisic acid in tomato seedlings Horticulture, Environment, and Biotechnology.56(3):294304 pISSN 2211-3452; eISSN 2211-3460 Vu, N.T., S.H Kim, and I.S Kim 2015 Effect of grafting position, water content in substrate on the survival rate and quality of grafted tomato seedlings Journal of Agriculture, Life and Environmental Sciences 27(2): ISSN 22338322 Ngoc-Thang Vu, Hoang-Tung Vo, Ho-Min Kang, Young-Shik Kim, and Il-Seop Kim 2015 Improvement of tomato seedling quality in low temperature by application of silicate fertilizer Protected Horticulture and Plant Factory pISSN 2288-0992; eISSN 2288-100X (Submitted) 151 토마토 플러그묘 생산 과정중 기후순화와 저장조건이 활착율과품질에 미치는 영향 부 넉 탕 Vu Ngoc Thang 강원대학교 대학원 원예학과 접목 과정 동안 환경을 통제하기 위한 수많은 접목 절차와 기술이 널리 알려져 있음에도 불구하고 이러한 기술들을 활용한 접목 과정을 효 과적으로 보장하기 위해서는 반드시 기타 여러 요소들도 신중히 고려 해 야 한다 활착율과 토마토 묘의 품질을 높이기 위해 초기 연구 단계에서 온도제어와 습도 부분을 조사하였다 모든 대목 품종에서 20℃와 26℃일 때와 비교해 23℃일 때 가장 높은 활착율(84.0~87.4%)을 보였다 온도가 높은 경우 활착율이 하락하였고 감염된 식물의 비율은 증가했다 모든 온도 수준에서 상대습도가 높을수록 활착율이 상승했다 그러나 상대습 152 도가 증가될 때 병해충에 감염된 식물의 비율도 상당 증가했다 90% 상 대 습도 기간이 길수록 활착율이 증가한 반면에 10일 동안 계속해서 상 대습도를 90 %로 높였을 경우 활착율이 감소하였다 처음 2~3일 동안 상대습도를 높게 하였고(90%), 그 다음 회복 및 기후순화 기간 동안 온 도는 23도로 하여 상대습도를 낮게 하자(70%) 활착율과 접목된 토마토 묘의 품질이 향상되었다 위의 최적 조건을 기반으로 수분 함량이 기질 에 미치는 영향, 접목 위치에 미치는 영향력, 다양한 품종이 토마토 묘의 활착율과 품질에 미치는 영향력을 조사했다 기질의 수분 함량을 통제하 자 활착율과 묘의 품질이 상승되었다 가지 접목으로 물 함량을 중간 정 도로 한 경우와 대목 접목으로 물 함량을 높인 묘의 경우 최고의 조밀도 와 최적의 활착율(100%)이 관찰되었다 서로 다른 두 접목 위치에 따른 활착율 차이는 유의성이 나타나지 않았지만 접목 위치가 접목된 토마토 묘의 성장에는 영향을 미쳤다 접수 품종간의 활착율에는 유의성을 보였 지만 대목 품종간의 활착율에는 유의성이 나타나지 않았다 다수의 연구 에서 광질(light quality)이 식물의 성장과 발달에 미치는 영향력에 대해 조사해 왔으며 대부분의 연구에서 성장, 광합성, 신진대사, 유전자 발현 을 집중적으로 연구한 반면에 광질이 어떻게 활착율과 묘목 품질에 영향 을 미치는지에 대해서는 밝혀진 바가 거의 없다 따라서 광질에 따른 단 153 기 발광이 활착율과 토마토 묘목 품질에 미치는 영향력에 대해 조사하였 다 접목 이전에 단기 발광을 가하는 경우 자연광 96.7%와 비교해서 활 착율이 모든 처리 부분에서 상당히 낮게 나타났다(27.8-66.7%) Red LED 광선에 대한 활착율이 WFL 처리와 비교해서는 통계학적으로 유의성을 보이지 않았지만 반면에 far-red LED와 blue LED 처리보다는 더 높게 나 타났다 암흑 처리에서 가장 낮은 활착율(27.8%)을 보였다 접목 이전에 빛의 강도를 변경시키는 것은 본 연구에서 활착율을 떨어뜨리는 요인으 로 나타났다 엽수, 엽록소, 엽면적, 뿌리의 생체중을 제외하고는 성장변 수 측면에서 봤을 때, 자연광, WFL, red LED 사이에는 유의성이 나타나 지 않았다 그러나 far-red LED, blue LED, 암흑에서 처리된 묘목의 경우 활착율이 하락하였다 접목 이후에 단기 발광을 가하는 경우 활착율이 증진되었다(68.5-100.0%) 최적 활착율(100%)의 경우 red LED에서 기록 되었지만 WFL 처리와 통계학적으로 차이점을 보이지는 않았다 최저 활 착율은 암흑 처리 부분에서도 관찰되었다 Red LED에 반응하는 식물 성 장은 접목 이후의 WFL과도 유사했다 그러나 접목 이후에 단기 발광을 적용하는 경우 far-red LED 처리 부분에서 최저 식물 성장 수치가 관찰되 었다 식물 성장변수의 경우 어둠과 blue LED로 처리한 묘목과 유사했지 만 red LED와 WFL과 비교해서는 더 낮은 수준을 보였다 접목 이후에 154 red LED 처리를 한 묘목의 경우 뿌리 형태학이 개선을 보이며 총 뿌리 면적, 뿌리 길이, 근단의 수가 증가되었다 Red LED로 접목 한 후 35일 째 묘의 품질이 상승했으며 식물 성장변수가 증가했다 특히, 조밀도와 총 뿌리 형태학이 다른 처리와 비교해서 더 많은 증가를 보였다 활착율 과 묘의 품질에 red LED가 미치는 영향력을 확인하기 위해 세 가지 대 목 품종에서 red LED와 무광(암흑처리) 요소를 조사했다 그 결과 red LED가 암흑 처리와 비교해서 더 높은 활착율을 나타냈다 암흑 처리에 서 대목 품종의 활착율이 상당한 변화를 나타냈지만 red LED 처리 부분 에서는 아무런 변화도 나타내지 않았다 또한 red LED 처리에서 감염된 식물의 비율이 하락했다 Red LED에서의 묘의 품질이 암흑 처리와 비교 해서 더 좋게 나타났으며 성장변수들이 개선되었다 큰 규모의 채소 모종 생산이 이루어지는 온실의 경우 플러그 묘의 길이 조절이 핵심 문제이다 최근 들어 몇 가지 방법들이 개발되었음에 도 저온에서 묘를 저장하는 것이 묘의 초장을 조절하는 가장 효과적인 기술이다 저온 저장의 경우 묘의 성장과 발달을 중단시키거나 억압할 때 활용될 수 있으며 이와 동시에 묘의 품질을 보존하고 성장에 미치는 악영향을 방지할 수 있다 따라서 토마토 묘의 성장과 품질에 저장 온도 가 미치는 영향력을 조사하였다 모든 저온 저장에서 묘의 초장이 원활 155 하게 이루어지지 않았음을 알 수 있었다 4℃의 경우 토마토 묘를 장기 간 보존하는데 적합하지 않은 온도였다 식물의 초장과 엽수가 저장 온 도가 내려갈수록 낮아졌다 잎의 엽록소의 경우 저장 기간이 길어 질수 록 감소하였다 그러나 자연 조건에서 10일 이상 두자 묘의 엽록소 수치 가 13℃와 비교해서 더 낮은 수준을 나타냈으며 이와는 다르게 10℃, 7℃ 와 비교해서는 더 높은 수준을 나타냈다 10일 또는 20일 동안 저장했을 경우 10℃와 7℃에서 묘가 저온 장해를 입고 잎이 구부러지는 현상이 관찰되었다 그러나 13℃에 저장된 묘의 경우는 이러한 현상이 관찰되지 않았다 7℃와 10℃에 저장된 묘의 잎의 확장 시기와 저온 장해 지수의 경우 저장 기간이 길어 질수록, 저장 온도가 낮아질수록 더 높아졌다 전 체적으로는 저온에서 개화시기가 늦어 졌다 저장 기간이 길어 지고 저 장 온도가 낮아질수록 개화시기가 더 늦어 졌다 10일 또는 20일 동안 저장 한 후, 토마토 묘의 성장변수가 저장 온도가 하락할수록 큰 하락세 를 나타냈다 여기서 잎 엽록소 수치, 구체적인 잎 면적, 평균 뿌리 둘레 는 예외였다 식물의 크기, 엽면적을 제외하고는 10℃와 7도℃의 묘의 성장변수에는 통계학적으로 유사성이 나타나지 않았다 저장 온도가 내 려가면 성장변수도 상당한 하락세를 나타냈지만 저장 10일 이후에는 13℃, 10℃, 7℃ 환경의 묘의 조밀도가 자연 조건(Nature)과 유사하게 나 156 타났다 그러나 저장 20일 후에는 묘의 조밀도가 저온 저장 상태에서 상 당한 하락세를 나타냈다 규소(Si)의 경우 식물 성장을 위한 중요 요소에 포함되고 있으며, 다종의 식물 성장과 발달 자극에 규소가 주는 이로운 역할이 전반적으로 확인되고 있다 또한 규소의 경우 다양한 비생물적 스트레스를 효과적으 로 감소시킨다고 알려져 있다 따라서 본 연구에서는 규소를 적용함으로 써 토마토 묘의 품질을 개선시키고자 했다 실험 결과에 따르면 규소가 성장변수와 뿌리 형태학을 증가시킴으로써 토마토 묘의 성장과 발달을 자극시켰다 규소 농도를 32mM으로 증가시키자 증산 속도가 하락하였고 기공저항성이 상승했다 저온 보관 시 규소처리가 잎 면적 피해를 감소 시킴으로써 저온장해 지수를 낮췄다 식물 호르몬 아브시스산(ABA)은 식 물 성장과 발달의 다양한 측면 그리고 스트레스 저항에 있어서 매우 중 요한 역할을 한다 이와 관련해서 본 연구에서는 ABA 적용을 통한 토마 토 묘의 비생물 스트레스 저항력 증진을 목표로 실험을 진행하였다 ABA 의 적용으로 토마토 묘의 성장변수 대부분이 감소되었다 그러나 ABA 처리로 잎 면적의 피해가 감소하며 저온에서의 묘의 품질이 상승되었다 또한 ABA는 토마토 묘 잎의 증산속도를 늦춤으로써 건조함이 개선되었 다 통제집단과 비교해서 50mg/L 처리 묘목의 증산속도가 낮고 기공확 157 산저항이 높긴 했지만 100mg/L의 ABA 처리와 비교했을 때 50mg/L 처 리 묘의 증산속도는 훨씬 더 빠르고 기공저항성은 훨씬 낮았다 따라서 통제처리의 경우 시들음 시작 시점이 3일째에 관찰되었지만 ABA 50mg/L과 100mg/L에서는 각각 관수(irrigation) 없이 5일과 7일째에 관찰 되었다 장기간 저장 시 토마토 묘의 품질을 개선시키기 위해서 ABA 100mg/L와 규소 16mM을 처리 하였다 처리 방법은 각각 3일동안 하루 에 한번 엽면시비하였고, 20일 동안 3일에 한번 뿌리에 관수하는 방식으 로 공급 하였다 마지막 처리 기준으로 24시간 이 후 묘의 환경온도 7℃, 10℃의 서로 다른 온도로 유지되는 생장실로 이동시켰다 저장 기간 동 안 토마토 묘의 초장이 규소 처리 시 증가했지만 ABA처리 당시 하락하 였다 동일 저장 기간 동안 규소 처리를 할 때와 아무 처리 하지 않을 때의 엽수는 비슷하였지만 ABA 처리를 가하자 상당히 낮은 수치를 보였 다 저장 기간 동안 모든 처리 과정에서 7℃에 저장된 묘의 엽록소 함량 이 10℃ 보다 낮게 나타났으며 ABA 처리를 받은 묘의 엽록소 함량은 규소 처리와 아무런 처리를 받지 않는 묘에 비해 높게 나타났다 규소와 ABA는 엽면적의 피해를 감소시킴으로써 저온에서 묘의 품질을 증진시켰 다 하지만 ABA 처리에서 묘의 저온 장해 지수가 규소 처리와 비교해서 더 낮게 나타났다 규소와 ABA가 2, 3, 4번째 화방의 꽃 수량을 증가시켰 158 으며 두 온도 모두에서 2번째, 3번째 송이의 과실의 수도 증가했으며, ABA 처리를 한 식물의 꽃과 과실의 수가 규소 처리를 한 것과 비교해서 더 높게 측정되었다 159 ... the graft- take ratio and quality of grafted tomato seedlings To investigate the effect of light quality on the graft- take ratio and quality of grafted tomato seedlings Improvement of seedling quality. .. growth and stress tolerance of tomato seedlings To improve seedling quality of stored tomato by silicon and ABA application Chapter II Improving the Graft- take Ratio and Quality of Grafted Tomato Seedlings... graft- take ratio and quality of grafted tomato seedlings… 41 2.4.3.3 Effect of red LED during the healing and acclimatization period on the graft- take ratio and quality of grafted tomato seedlings…