Title Page
ABSTRACT
Contents
INTRODUCTION 11
LITERATURE REVIEW 13
1. Garden culture in Korea 13
2. Korean endemic plants for gardens 14
3. Genus Hosta 15
4. Hosta minor 18
5. Hosta yingeri 19
6. Heat stress and heat waves 21
7. Plant defense mechanism against heat stress 23
MATERIALS AND METHODS 26
1. Plant materials 26
2. Methods 28
2.1. Heat treatment 28
2.2. Measurement and analysis 31
2.3. Statistical analysis 41
RESULTS 42
1. Growth responses to heat stress 42
1.1. Change in biomass 42
1.2. Ornamental value 48
2. Stomatal and photo-physiological responses to heat stress 54
2.1. Stomatal response 54
2.2. Photosynthetic and gas exchange parameters 57
2.3. Chlorophyll and carotenoid contents 59
2.4. Chlorophyll fluorescence 62
3. Proteomic responses to heat stress 68
DISCUSSION 73
1. Growth responses to heat stress 73
2. Stomatal and photo-physiological responses to heat stress 74
3. Proteomic responses to heat stress 77
LITERATURE CITED 80
Appendices 99
Appendix 1. Change in substrate water content in the control (25/15℃) and under heat stress treatment (35/25℃). 99
Appendix 2. 2D gel electrophoresis image of Hosta minor and H. yingeri protein expression after five weeks of heat stress treatment (this result was from the second experiment). A: H. minor in the control (CK); B: H. minor under heat stress treatment (HST); C: H. yingeri in the CK; D: H. yingeri under HST. The x-axis represents the isoelectric point (pl) and the y-axis represents the molecular weight (MW). 100
Appendix 3. Cluster gram of the Hosta minor and H. yingeri protein expression after 5 weeks of heat stress treatment (this result was from the second experiment). HMC: H. minor in the control (CK); HMHS: H. minor under heat stress treatment (HST); HYC: H. yingeri in the CK; HYHS: H. yingeri under HST. The brighter the red color, the higher the ratio, which can be interpreted as a relative increase in expression compared to other samples. The darker the color, the lower the expression in that sample compared to the other samples. 101
Appendix 4. Cluster gram of protein expression by expression patterns in Hosta minor and H. yingeri after 5 weeks of heat stress treatment (this result was from the second experiment). HMC: H. minor in the control (CK); HMHS: H. minor under heat stress treatment (HST); HYC: H. yingeri in the CK; HYHS: H. yingeri under HST. The brighter the red color, the higher the ratio, which can be interpreted as a relative increase in expression compared to other samples. The darker the color, the lower the expression in that sample compared to the other samples. 102
Appendix 5. Effect of heat stress on the expression of Hosta minor and H. yingeri proteins after 5 weeks (this result was from the second experiment). Proteins from cluster 3 were identified. HMC: H. minor under control (CK); HMHS: H. minor under heat stress treatment (HST); HYC: H. yingeri in the CK; HYHS: H. yingeri under HST. 103
ABSTRACT IN KOREAN 104
Table 1. Environmental conditions of the experiment. 30
Table 2. Initial growth parameters of Hosta minor and H. yingeri. 45
Table 3. Effect of heat stress on the growth parameters of Hosta minor and H. yingeri after 5 weeks. 46
Table 4. Effect of heat stress on the leaf color of Hosta minor and H. yingeri after 5 weeks. 50
Table 5. Effect of heat stress on the photosynthetic and gas exchange parameters of Hosta minor and H. yingeri after 5 weeks. 58
Table 6. Effect of heat stress on the chlorophyll and carotenoid contents of Hosta minor and H. yingeri after 5 weeks. 61
Table 7. Effect of heat stress on the chlorophyll fluorescence of the entire leaf of Hosta minor and H. yingeri after 5 weeks. 64
Table 8. Effect of heat stress on the chlorophyll fluorescence of no-chlorotic leaf of Hosta minor and H. yingeri after 5 weeks. 67
Table 9. Effect of heat stress on the protein expression of Hosta minor and H. yingeri after 5 weeks. The proteins from cluster 4 were identified. HMC: H. minor in the CK; HMHS: H. minor under HST; HYC: H. yingeri in the CK; HYHS: H. yingeri under HST. 72
Fig. ⅰ. Hosta planted in the gardens, Royal Botanic Gardens, Kew in England (left) and Chollipo Arboretum in Korea (right). 16
Fig. ⅱ. The appearance and inflorescence of the six Hosta species native to Korea. A: H. capitata; B: H. clausa; C: H. jonesii; D: H. minor; E: H.... 17
Fig. ⅲ. Habitat distribution of Hosta minor and H. yingeri. A-B: appearance; a-b: habitat distribution. A, a: H. minor; B, b: H. yingeri. Scale... 20
Fig. ⅳ. Heat wave days and maximum temperature in Korea from 1991 to 2023 (KMA, 2023a; KMA, 2023c). 22
Fig. 1. Initial growth stage in Hosta minor (A) and H. yingeri (B). Scale bar=100 mm. 27
Fig. 2. View of Hosta species experiment in the growth chamber. 30
Fig. 3. Weekly change in the leaf number of Hosta minor (A) and H. yingeri (B) under heat stress treatment for 5 weeks. Error bars indicate the standard deviation (n=6). ns and * are not significant or significant, respectively, at p 〈0.05 according to Student's t-test.[이미지참조] 44
Fig. 4. Effect of heat stress on the root of Hosta minor and H. yingeri after 5 weeks. Scale bar=20 mm. 47
Fig. 5. Weekly change in the leaf color of Hosta minor and H. yingeri under heat stress treatment for 5 weeks. L* value of H. minor (A) and H. yingeri... 51
Fig. 6. Effect of heat stress on relative chlorosis rate of Hosta minor and H. yingeri after 1 week (A, B), 3 weeks (C, D), and 5 weeks (E, F). Error bars... 52
Fig. 7. Weekly change in the growth response of Hosta minor and H. yingeri under heat stress treatment for 5 weeks. Scale bar=50 mm. 53
Fig. 8. Effect of heat stress on the stomatal pore area of Hosta minor and H. yingeri after 5 weeks. Error bars indicate the standard deviation (n=15).... 55
Fig. 9. Effect of heat stress on the stomatal pore opening and closing of Hosta minor and H. yingeri after 5 weeks. A: H. minor under control... 56
Fig. 10. Weekly change in the SPAD value of Hosta minor (A) and H. yingeri (B) under heat stress treatment for 5 weeks. Error bars indicate the standard deviation (n=9 in initial value, weeks 1, 2,and 3; n=5 in week 4; n=4 in week 5). ns, *, **,and *** not...[이미지참조] 60
Fig. 11. Effect of heat stress on the chlorophyll fluorescence of Hosta minor and H. yingeri after 5 weeks. 65
Fig. 12. Effect of heat stress on the OJIP kinetics of chlorophyll fluorescence of Hosta minor (A) and H. yingeri (B) after 5 weeks (n=3). 66
Fig. 13. 2D gel electrophoresis image of the protein expression of Hosta minor and H. yingeri after 5 weeks of heat stress treatment. A: H. minor in... 69
Fig. 14. Clustergram of the protein expression in Hosta minor and H. yingeri after 5 weeks of heat stress treatment. HMC: H. minor under control... 70
Fig. 15. Clustergram of the protein expression by expression patterns in Hosta minor and H. yingeri after 5 weeks of heat stress treatment. HMC: H.... 71
Fig. 16. Summary of comparative analysis of heat tolerance between Korean endemic Hosta minor and H. yingeri. Gray boxes were studied in this research. Other factors affecting the response under heat stress were also presented in the scheme. 79