Title Page

ABSTRACT

Contents

ABBREVIATIONS 18

INTRODUCTION 20

LITERATURE REVIEW 24

1. Poplar and biomass production 24

2. Plant growth promoting rhizobacteria (PGPR) and plant growth 32

3. The responses of growth and physiology of plant under plant growth promoting rhizobactria (PGPR) 36

4. Bacillus subtilis 46

5. Wood pellet 49

MATERIALS AND METHODS 55

1. Plant materials 55

1.1. Plant materials in SRC (Short rotation coppice, Experiment I) 55

1.2. Plant materials in greenhouse environment (Experiment II) 55

2. Site description and experimental design 58

2.1. Research site in SRC (Short rotation coppice, Experiment I) 58

2.2. Experiment plot in greenhouse environment (Experiment II) 61

3. Microclimate 63

3.1. Meteorological data collection in SRC (Short rotation coppice, Experiment I) 63

3.2. Meteorological data collection in greenhouse environment (Experiment II) 64

4. Bacillus subtilis JS bacterial culture 67

4.1. Bacillus subtilis JS culture in culture medium 67

4.2. Bacillus subtilis JS treatment on the plants 67

5. Soil chemical analysis 70

6. Plant analysis 72

6.1. Adaptability 72

6.2. Analysis of plant growth 74

6.3. Analysis of plant physiology 77

6.4. Analysis of plant morphology 83

7. Wood pellet utilization analysis 85

7.1. Sampling 85

7.2. Analysis of moisture content 85

7.3. Analysis of ash content 86

7.4. Analysis of net caloric value 86

7.5. Analysis of lignin and carbohydrate composition 87

7.6. Analysis of harmful chemical substance (N, Cl, S) and heavy metal (As, Cd, Cr, Cu, Pb, Hg, Ni, Zn) in dry mass 87

8. Statistical analysis 88

RESULTS 89

1. Soil chemical properties (Experiment I) 89

2. Plant growth 90

2.1. Adaptability (Experiment I) 90

2.2. Tree height and root collar diameter 91

2.3. Leaf area and leaf mass per area (LMA) (Experiment II) 97

2.4. Biomass (Experiment I) 99

2.5. Relative growth rate (RGR) (Experiment I) 102

2.6. Seedling quality index (SQI) (Experiment II) 103

3. Physiological characteristics 105

3.1. Net photosynthetic rate (Anet)(이미지참조) 105

3.2. Water use efficiency (WUE) 107

3.3. Chlorophyll and carotenoid contents 110

3.4. Leaf temperature (Experiment II) 115

3.5. Leaf nitrogen and phosphorus contents (Experiment II) 117

3.6. Root activity (Experiment II) 119

3.7. Soil respiration (Rs) (Experiment I) 121

4. Morphological parameters 123

4.1. Stomata characteristics (Experiment I) 123

4.2. Anatomical characteristics (Experiment I) 126

5. Wood pellet utilization 131

5.1. Moisture contents (Experiment I) 131

5.2. Ash contents (Experiment I) 134

5.3. Net calorific value (Experiment I) 135

5.4. Lignin and carbohydrate composition (Experiment I) 136

5.5. Harmful chemical substance (N, Cl, S) and heavy metal (As, Cd, Cr, Cu, Pb, Hg, Ni, Zn) contents (Experiment I) 139

DISCUSSION 142

Soil chemical property (phosphorus content) in SRC 142

Plant growth and chlorophyll content by PGPR 143

Plant growth and root vitality by PGPR's root exudate 145

Relationship between nitrogen content and plant growth by PGPR 147

Phosphate content and plant growth by PGPR 148

Changes of leaf area and leaf mass per area (LMA) by PGPR 151

Biomass 151

Change of photosynthetic rate and water use efficiency by PGPR 152

Rhizobacteria and soil respiration (Rs) 154

Stomata characteristics 156

Anatomical characteristics 157

Moisture contents of wood biomass 161

Lignin contents and heating rate 162

Ash contents of wood biomass 164

CONCLUSION 167

LITERATURE CITED 170

SUMMARY IN KOREAN 206

Table 1. Plant growth-promoting rhizobacteria 33

Table 2. Greenhouse gas(GHG) reduction effectiveness in fuel switching from Bunker-C oil and kerosene to wood biomass 52

Table 3. Comparison of CO₂ emissions from various fuels 54

Table 4. Container type used for this greenhouse experiment (Experiment II). 57

Table 5. List of poplar clones used for this experiment (Experiment II). 61

Table 6. Treatments to Populus euramericana and Populus deltoides × P. nigra... 69

Table 7. Soil characteristics in SRC in Saemanguem reclaimed land experimental forest (Experiment I). 71

Table 8. Categories of leaf damage and crown damage in poplar tree 73

Table 9. Total chlorophyll, carotenoid contents and chlorophyll a/b ratio of poplar leaf in SRC (Experiment I). 112

Table 10. Total chlorophyll, carotenoid contents and chlorophyll a/b ratio of poplar leaf in greenhouse (Experiment II). 113

Table 11. Changes of stomata traits after B. subtilis JS treatment. 124

Table 12. Anatomical traits of Populus euramericana grown in different microbial... 130

Table 13. Specification for Korean wood pellet quality criteria 132

Table 14. Effects of B. subtilis JS treatment on the lignin and carbohydrate composition of Populus euramericana in SRC. 137

Table 15. Harmful chemical substance (N, Cl, S) and heavy metal contents from dry mass of Populus euramericana planted in SRC... 140

Table 16. Anatomical characteristics of Populus euramericana 159

Figure 1. Farmland area in the world (left) and changes of fertilizer application... 22

Figure 2. The biomass production after 3-year-growing seasons of Populus spp. in SRC 31

Figure 3. Plant-growth-promoting mechanism of PGPR 35

Figure 4. Effect of root exudate on nutrient availability and uptake by rhizosphere... 41

Figure 5. Functions of plant growth-promoting rhizobacteria 43

Figure 6. Putative mechanism of growth promotion and enhanced disease resistance on plant by volatiles of Bacillus subtilis JS 48

Figure 7. Initial growth picture of seedlings of Populus euramericana and Populus deltoides × P. nigra treated B. subtilis JS 56

Figure 8. The location of the research site at SRC(short rotation coppice) in Saemanguem reclaimed land (Experiment I). 59

Figure 9. Site description of the research siteIplanted Populus euramericana in March of 2014 60

Figure 10. Illustration of experimental design of Populus euramericana and Populus deltoides × P. nigra seedlings in February of... 62

Figure 11. Climatic condition of research site at SRC (Experiment I). 65

Figure 12. Climatic condition of greenhouse environment (Experiment II). 66

Figure 13. Morphological phenotypes of strain B. subtilis JS on NB medium. 68

Figure 14. Soil irrigation of B. subtilis JS strain in SRC (Experiment I). 68

Figure 15. The adaptability index of Populus euramericana grown in different... 90

Figure 16. Tree height and root collar diameter of Populus euramericana grown in... 92

Figure 17. Shoot length of Populus euramericana and Populus deltoides × P. nigra grown in different microbial agent (B. subtilis... 94

Figure 18. Shoot diameter of Populus euramericana and Populus deltoides × P. nigra grown in different microbial agent (B.... 95

Figure 19. Site view of Populus euramericana and Populus deltoides × P. nigra grown in different microbial agent (B. subtilis JS)... 96

Figure 20. Sampled leaf size of Populus euramericana and Populus deltoides × P.... 97

Figure 21. Leaf area and leaf mass per area of Populus euramericana and Populus... 98

Figure 22. aboveground biomass of Populus euramericana grown in different... 100

Figure 23. Regression models for estimation of aboveground biomass production... 101

Figure 24. Relative growth rate of Populus euramericana grown in different... 103

Figure 25. Seedling quality index of Populus euramericana and Populus deltoides × P.... 104

Figure 26. Net photosynthetic rate of Populus euramericana grown in different... 105

Figure 27. Net photosynthetic rate of Populus euramericana and Populus deltoides... 107

Figure 28. Water use efficiency of Populus euramericana grown in different... 108

Figure 29. Water use efficiency of Populus euramericana and Populus deltoides ×... 109

Figure 30. Difference of temperature between leaf and air of Populus euramericana... 116

Figure 31. Total nitrogen contents in leaves of Populus euramericana and Populus... 118

Figure 32. Total phosphate contents in leaves of Populus euramericana and... 118

Figure 33. Root development of Populus euramericana and Populus deltoides × P.... 119

Figure 34. Root vitality and formazan contents of Populus euramericana and... 120

Figure 35. Seasonal pattern of soil respiration of Populus euramericana grown in... 121

Figure 36. Seasonal pattern of soil temperature of Populus euramericana grown in... 122

Figure 37. Stomata features images of Populus euramericana grown in different... 124

Figure 38. Stomata frequency of Populus euramericana grown in different microbial... 125

Figure 39. Vessel features images of Populus euramericana grown in different... 127

Figure 40. Vessel features images of Populus euramericana grown in different... 128

Figure 41. Vessel features images of Populus euramericana grown in different... 129

Figure 42. Moisture contents in dry mass of Populus euramericana grown in... 133

Figure 43. Ash contents in dry mass of Populus euramericana grown in different... 134

Figure 44. Net carorific value of dry mass of Populus euramericana grown in... 135

Figure 45. TGA and DSC curves of wood and biomass component under nitrogen... 163

Figure 46. Summary of the effect of Bacillus subtilis JS on the growth, physiological and morphological aspects on Populus... 166

 본 연구의 목적은 억새의 근권에서 분리한 Bacillus 계통의 식물생장촉진 근권 미생물(Plant growth promoting rhizobacteria)을 간척지에 조성된 포플러류 (Populus euramericana와 Populus deltoides × P. nigra)에 관수했을 때, 생육, 생리적 및 목재특성에 미치는 영향을 고찰하는 것이다.

실험은 두 가지의 방식, 즉, 전북 김제시 새만금간척지 내 배후도시 유보용지에 위치한 단벌기 바이오매스 생산 시험림에서 실시한 실험I과 서울시립대학교 벤로형 유리온실에서 실시한 실험II로 구분하였다.

실험I은 새만금 간척지에 토양개량제 목초탄이 각각 100% (200kg ha-1)와 150% (300kg ha-1)로 복토 처리된 단벌기 바이오매스 생산 시험림을 대상으로 억새의 근권에서 동정한 식물생장촉진 근권 미생물인 Bacillus subtilis JS토양관수처리에 따른 포플러 묘목의 생육 및 생리적 특성 그리고 형태적 특성 및 목재펠릿 활용가능성을 조사하기 위해 수행되었다. 2014년 3월에 조성된 포플러 단벌기 바이오매스 생산 시험림에서 2014년 5월부터 10월까지 그리고 이듬해인 2015년 5월부터 8월까지 모니터링 및 조사를 실시하였다. 수고 및 근원경, 바이오매스 생산량, 순 광합성률, 수분이용효율, 총 엽록소 함량 및 카로티노이드 함량, 토양호흡, 잎의 기공과 줄기의 세포구조 특성, 건조목의 함수율, 회분량, 발열량 및 유해성분함량, 리그닌과 홀로셀룰로오즈함량 등을 조사하였다.

실험II는 단벌기 바이오매스 생산림에서 우수한 바이오매스 생산량을 보이는 것으로 알려진 포플러 클론 4종류 (Dorskamp, Eco28, I-476, Venziano)를 서울시립대학교 벤로형 유리온실에 2015년 2월에 가지 삽목 번식하여 당해년도 5월부터 9월까지 4개월간 묘목의 품질과 생리활성의 변화를 관찰하였다. 연구내용으로는 맹아길이 및 직경, 엽면적, 묘목품질지수, 순 광합성률, 수분이용효율, 총 엽록소 함량 및 카로티노이드 함량, 엽온, 엽내 질소와 인 함량, 뿌리활력 등을 조사하였다.

실험 I과 실험 II의 생장 및 생리적 특성들을 조사·분석하였다. 수고와 흉고직경, 엽면적, 바이오매스, 광합성률과 수분이용효율은 PGPR로 알려진 B. subtilis JS가 처리된 포플러 묘목이 처리되지 않은 묘목에 비해서 높았고, 총 엽록소 함량 및 카르티노이드 함량과 엽온 또한 B. subtilis JS가 처리된 포플러 묘목이 무처리에 비해서 유의적으로 높았다 (p 〈 0.05). 형태학적 변수들을 조사한 결과 기공의 변화는 B. subtilis JS의 처리에 따라 포플러 묘목의 기공의 크기는 증가하였으며 통계적으로 유의하였으나 기공밀도의 변화는 통계적으로 유의하지 않았다. 목재의 세포 도관의 크기 또한 통계적으로 유의하지는 않았다. 목재펠릿의 활용가능성 측면으로는 B. subtilis JS가 처리된 포플러 묘목과 무처리 묘목 모두 함수율, 발열량은 1등급 이내, 회분함량은 3등급 이내로 목재펠릿 품질기준에 부합하였으며, 유해화학물질과 중금속 함량도 기준치 이내로서 목재펠릿으로 활용하기에 적합하다고 판단되었다.

이상의 결과를 종합하면, B. subtilis JS가 처리된 포플러 묘목이 처리하지 않은 묘목에 비해 생장과 생리적 활성이 증가하는 것을 확인하였다. 또한, 목재펠릿에서 중요한 질적인 측면은 떨어뜨리지 않으면서 포플러의 생육과 생리적인 향상에 기여할 수 있는 가능성을 확인할 수 있었다. 지금까지 PGPR처리는 농작물을 대상으로 처리한 실험에서 생장 및 생리활성변화에 대한 연구결과가 대부분이었는데, PGPR을 목본식물인 포플러에 처리하였을 때에도, 지상부 바이오매스를 향상시킨 결과를 얻었다. 이는 단벌기 맹아생산림에 대한 PGPR의 활용가능성을 제시할 수 있는 연구결과로서 의의가 있다.