-
三峡大坝于2009年竣工,旨在控制洪水、方便航行、供水和发电[1-2]。根据大坝“蓄水清排浊”方案,其6-9月为低水位运行期(坝前145 m 高程低水位为下限);9月至来年5月为高水位运行期,期间整个消落带被全部淹没(坝前175 m高程征地线为上限)。因此,与我国自然河岸带的“夏季淹没、冬季干旱”特征不同,三峡水库消落带具有“夏季干旱、冬季淹没”的特点[3]。目前,在三峡水位正常运行下,三峡库区消落带已经历了很长时间的反季节性的“水淹-干旱-水淹”的影响,这是干扰河岸带植物生长的主要因素。消落带植被所面临的水文状况复杂,其夏季受干旱胁迫时长超过1个月,同时,植物在经历夏季很长时间的干旱胁迫后,就会面对接踵而至的长达5个月的水淹胁迫,这在一定程度上为植被恢复筛选适生物种带来了更加严峻的挑战。自蓄水以后,由于植物对非季节性水淹逆境的不适应性,目前已导致三峡库区消落带植被出现严重退化现象,这直接干扰了河岸生境的结构和功能;同时,三峡库区消落带属于“自然-经济-社会”的复合系统,对外界干扰非常敏感,目前除面临严峻的生态环境问题外,还面临流行性疫情多发等经济社会问题。有研究指出,三峡库区秭归段消落带受反季节运行模式影响,其冬季淹水、夏季干旱的特殊干湿交替生境使不同土层土壤的酸碱度、淋溶程度、可挥发硫化物等理化性质和环境参数产生变异,从而影响了土壤中各类型重金属的迁移转化规律,通过污染评价可得其所在消落带土壤大多受重金属铁、锰复合型污染[4]。
湿地松(Pinus elliottii Engelmann)是松科松属的一种常绿乔木,原产地树高达30 m,胸径90 cm;树皮灰褐色或暗红褐色;枝条生长3~4 轮·a−1;针叶深绿色,2~3针一束并存,有气孔线;球果窄卵圆形或圆锥形;种子卵圆形,种翅易脱落;常适生于低山丘陵地带,耐水湿,生长势常比同地区的马尾松(P. massoniana Lambert)或黑松(P. thunbergii Parlatore)好,很少受松毛虫危害;对气温适应性较强,能忍耐40℃的绝对高温和−20℃的绝对低温;在中性以至强酸性红壤丘陵地以及表土50~60 cm以下铁结核层和沙黏土地均生长良好,而在低洼沼泽地边缘尤佳,但也较耐旱,在干旱贫瘠低山丘陵能旺盛生长;抗风力强,其根系可耐海水灌溉,但针叶不能抗盐分的侵染,为最喜光树种,极不耐阴,分布极广泛;在中国北纬32°以南的平原,向阳低山均可栽培,可作为经济树种,也可作为风景园林和水土保持林[5]。目前,国内外对湿地松展开了包括生物学特征、光合特性、施肥状态下的生长反应等相关研究[6-11]。三峡水库水位运营特性使消落带周期性处于“干旱-水淹交替”的生境,为探索三峡水库消落带实际“干旱-水淹交替”生境下湿地松的耐受性能,揭示其变化规律,本研究以2年生适生植物湿地松为研究对象,通过模拟消落带“夏季干旱-冬季淹水”的实际生境环境,研究在特定生境条件下湿地松的光合性能及生理生化特性的变化规律,探索前期干旱胁迫是否会增加植物对后期水淹胁迫的敏感性等科学问题,为三峡水库消落带植被恢复奠定基础。
水淹持续胁迫对湿地松光合特性及生理生化的影响
Effects of Continuous Flooding Stress on Photosynthetic Characteristics and Physiological and Biochemical Characteristics of Pinus elliottii
-
摘要:
目的 分析三峡库区消落带经历冬季水淹持续胁迫后对幼苗针叶光合特性以及生理生化的影响,揭示其变化规律,为消落带分区段监测和治理及植被恢复提供重要的科学依据。 方法 本研究以2年生湿地松幼苗为试验材料,研究了经历夏季干旱后,通过人为设置对照组、根淹组和全淹组等来模拟长达5个月的冬季水淹持续胁迫对幼苗针叶光合特性以及生理生化的影响。 结果 表明:经历夏季干旱胁迫45 d后,随着水淹时间增加,根淹组1和全淹组2植物的净光合速率(Pn)呈现出“下降-平缓”的趋势,但根淹组3和全淹组4植株的Pn处于一直下降趋势,且60 d后的Pn低于前者,水淹150 d后,湿地松的Pn分别比初始值下降30.9%、33.0%、51.9%和62.3%;同时,水淹显著降低了针叶气孔导度(Gs)和蒸腾速率(Tr)。通过比较Ci和Ls(气孔限制值)的关系得出:湿地松Pn下降前期主要由气孔因素决定,而后期则大多由非气孔因素决定。根淹组植株可溶性蛋白含量在淹水阶段大多与对照组植株差异不明显;全淹组的湿地松针叶内可溶性蛋白含量在淹水初期(水淹前60 d)出现了显著的增加,而在水淹后期逐渐下降。水淹45~60 d时,湿地松针叶内的超氧化物歧化酶(SOD)活性显著高于对照。不同淹水处理下,湿地松在水淹前30 d内丙二醛(MDA)含量均与对照组相比差异不显著,但水淹60 d后,湿地松针叶中的MDA含量显著增加并逐渐稳定在一定水平。 结论 这些研究结果对未来消落带适生物种选择以及植被恢复与重建具有重要的参考价值。 Abstract:Objective To study the effects of continuous flooding on leaf photosynthetic characteristics and physiological and biochemical characteristics of young plant. Method The Zigui section of the Three Gorges Reservoir riparian zone is affected by the water level operation of winter storage and summer discharge, forming a "drought-flooding-drought" water level fluctuation model, which makes the ecological environment of the riparian zone facing severe challenges. In this study, two-year-old Pinus elliottii seedlings were divided into six groups (including two control groups) with different initial drought and then flooding treatments and to study the effects of a simulated five-month winter flooding stress on photosynthetic characteristics and physiological and biochemical characteristics of seedling leaves after 45 days of drought stress. Result The results showed that with the increase of flooding time, the net photosynthetic rate of Group 1 (initially under mild drought stress and then root-flooded) and Group 2 (initially under mild drought stress and then full-flooded) showed a "decline-gentle" trend, but the net photosynthetic rate of Group 3 (initially under moderate drought stress and then root-flooded) and Group 4 (initially under moderate drought stress and then full-flooded) showed a downward trend. After 60 days, the net photosynthetic rate was lower than that of the former. After 150 days of flooding, the net photosynthetic rate of P. elliottii decreased by 30.9%, 33.0%, 51.9% and 62.3% respectively compared with the original values. Meanwhile, water flooding significantly reduced the stomatal conductance and transpiration rate. By comparing the relationship between Ci and Ls, it is concluded that the decrease of net photosynthetic rate of P. elliottii was mainly determined by stomatal factors in the early stage, and non-stomatal factors in the later stage. The content of soluble protein in root-flooded groups was mostly not significantly different from that in the control group during the flooding stage, while the content of soluble protein in leaves of P. elliottii in full-flooded group increased significantly at the early stage (60 days before flooding), but decreased gradually at the later stage. At 45 to 60 days of flooding, the activity of SOD in P. elliottii needles were significantly higher than those in the control group. The MDA content of P. elliottii leaves in different flooding conditions was not significantly different from that of the control groups within 30 days before flooding, but after 60 days of flooding, the MDA content of P. elliottii leaves increased significantly and gradually stabilized to a certain level. Conclusion These results can provide reference for the selection of suitable species and vegetation restoration and reconstruction in Three Gorges Reservoir riparian zone. -
-
[1] New T, Xie Z. Impacts of large dams on riparian vegetation: applying global experience to the case of China’s Three Gorges Dam[J]. Biodiversity Conservation, 2008, 17(13): 3149-3163. doi: 10.1007/s10531-008-9416-2 [2] Yang F, Liu W, Wang J, et al. Riparian vegetation’s responses to the new hydrological regimes from the Three Gorges Project: Clues to revegetation in reservoir water-level-fluctuation zone[J]. Acta Ecologica Sinica, 2012, 32(2): 89-98. doi: 10.1016/j.chnaes.2012.02.004 [3] Pan X, Wan C, Zhang Z, et al. Protection and ecological restoration of water level fluctuation zone in the Three Gorges Reservoir[J]. Journal of Landscape Research, 2017, 9(1): 47-53. [4] 郭 燕, 程瑞梅, 杨 邵, 等. 三峡库区不同植被类型消落带土壤重金属含量的时空变异[J]. 生态学杂志, 2018, 37(8):2497-2504. [5] 叶功富. 滨海沙地湿地松与木麻黄混交林构建和调控技术研究[J]. 林业科学研究, 2002, 15(4):463-468. doi: 10.3321/j.issn:1001-1498.2002.04.017 [6] 张太平, 任 海, 彭少麟, 等. 湿地松(Pinus elliottii Engelm.)的生态生物学特征[J]. 生态科学, 1999, 18(2):8-12. doi: 10.3969/j.issn.1008-8873.1999.02.002 [7] 周 珺, 魏 虹, 吕 茜, 等. 土壤水分对湿地松幼苗光合特征的影响[J]. 生态学杂志, 2012, 31(1):32-39. [8] 王振夏, 魏 虹, 李昌晓, 等. 土壤水分交替变化对湿地松幼苗光合特性的影响[J]. 西北植物学报, 2012, 32(5):980-987. doi: 10.3969/j.issn.1000-4025.2012.05.021 [9] Ye Z. Effects of Submergence and Drought Alternation on Photosynthesis and Growth of Pinus elliottii Seedlings[J]. Scientia Silvae Sinicae, 2011, 47(12): 158-164. [10] 苏梦云, 刘昭息, 周国璋. 火炬松和湿地松幼苗蔗糖含量与生长潜势关系的研究初报[J]. 林业科学研究, 1997, 10(1):94-96. [11] 洪顺山, 胡炳堂. 湿地松幼林施肥五年生长反应[J]. 林业科学研究, 1997, 10(6):624-628. [12] Berry J A. Environmental Regulation of Photosynthesis[J]. Photosynthesis, 1982,2: 263-343. [13] 李合生. 植物生理生化试验原理与技术[M]. 北京: 高等教育出版社, 2000. [14] Grace S C, Logan B A. Acclimation of foliar antioxidant systems to growth irradiance in three broad-leaved evergreen species[J]. Plant Physiol, 1996, 112(4): 1631-1640. doi: 10.1104/pp.112.4.1631 [15] 张 晔, 李昌晓. 水淹与干旱交替胁迫对湿地松幼苗光合与生长的影响[J]. 林业科学, 2011, 47(12):158-164. doi: 10.11707/j.1001-7488.20111224 [16] 李昌晓, 钟章成, 刘 芸. 模拟三峡库区消落带土壤水分变化对落羽杉幼苗光合特性的影响[J]. 生态学报, 2005a, 25(8):1953-1959. [17] 李昌晓, 钟章成. 模拟三峡库区消落带土壤水分变化条件下落羽杉与池杉幼苗的光合特性比较[J]. 林业科学, 2005b, 41(6):28-34. [18] Pezeshki S R, Li S, Jr F D S, et al. Factors governing survival of black willow (Salix nigra) cuttings in a streambank restoration project[J]. Ecological Engineering, 2007, 29(1): 56-65. [19] Kozlowski T T. Responses of woody plants to flooding and salinity[J]. Flooding & Plant Growth, 1984, 1(7): 129-163. [20] Beckman T, Perry R, Flore J. Short-term flooding affects gas exchange characteristics of containerized sour cherry trees[J]. Hortscience A Publication of the American Society for Horticultural Science, 1992, 27(12): 1297-1301. [21] Yordanova R Y, Uzunova A N, Popova L P. Effects of short-term soil flooding on stomata behaviour and leaf gas exchange in barley plants[J]. Biologia Plantarum, 2005, 49(2): 317-319. doi: 10.1007/s10535-005-7319-6 [22] 刘泽彬, 程瑞梅, 肖文发, 等. 中华蚊母树(Distylium chinense)幼苗对秋、冬季淹水的生长及生理响应[J]. 湖泊科学, 2016, 28(2):405-413. doi: 10.18307/2016.0221 [23] Iwanaga F, Yamamoto F. Effects of flooding depth on growth, morphology and photosynthesis in Alnus japonica species[J]. New Forests, 2008, 35(1): 1-14. [24] Ridge I. Ethylene and growth control in amphibious plants[J]. Plant Life in Aquatic & Amphibious Habitats, 1987(5): 53-76. [25] 衣英华, 樊大勇, 谢宗强, 等. 模拟淹水对枫杨和栓皮栎气体交换、叶绿素荧光和水势的影响[J]. 植物生态学报, 2006, 30(6):960-968. doi: 10.3321/j.issn:1005-264X.2006.06.011 [26] Farquhar G D, Sharkey T D. Stomatal Conductance and Photosynthesis[J]. Annual Review of Plant Physiology, 1982, 33(1): 317-345. doi: 10.1146/annurev.pp.33.060182.001533 [27] Regehr D L, Bazzaz F A, Boggess W R. Photosynthesis, transpiration and leaf conductance of Populus deltoides in relation to flooding and drought[J]. Photosynthetica, 1975, 9(10): 52-61. [28] Liu Z, Cheng R, Xiao W, et al. Leaf gas exchange, chlorophyll fluorescence, non-structural carbohydrate content and growth responses of Distylium chinense, during complete submergence and subaerial re-emergence[J]. Aquatic Botany, 2015, 124: 70-77. [29] 陈 静, 秦 景, 贺康宁, 等. 水分胁迫对银水牛果生长及光合气体参数的影响[J]. 西北植物学报, 2009, 29(8):1649-1655. doi: 10.3321/j.issn:1000-4025.2009.08.024 [30] 王朝英, 李昌晓, 张 晔. 水淹-干旱胁迫对南川柳苗木生长及生理特性的影响[J]. 林业科学, 2013, 49(12):164-170. [31] Suleman P, Afzal M, Al-Hasan R. Temperature-induced changes of malondialdehyde, heat-shock proteins in relation to chlorophyll fluorescence and photosynthesis in Conocarpus lancifolius (English.)[J]. Acta Physiologiae Plantarum, 2013, 35(4): 1223-1231. doi: 10.1007/s11738-012-1161-1 [32] Fadzilla N M, Finch R P, Burdon R H. Salinity, oxidative stress and antioxidant responses in shoot cultures of rice[J]. Journal of Experimental Botany, 1997, 48(2): 325-331. doi: 10.1093/jxb/48.2.325 [33] Yang Y, Han C, Liu Q, et al. Effect of drought and low light on growth and enzymatic antioxidant system of Piceaasperata seedlings[J]. Acta Physiologiae Plantarum, 2008, 30(4): 433-440. doi: 10.1007/s11738-008-0140-z [34] 吴 寒. 活性氧在植物体内的作用及其清除体制[J]. 广东蚕业, 2018, 52(3):18. [35] Alexander H,Jörg L, Ivano B,et al . Effects of aluminium treatment on Norway spruce roots: Aluminium binding forms, element distribution, and release of organic substances[J]. Plant and soil, 2000, 216(1): 103-116. [36] 贺燕燕, 王朝英, 袁中勋, 等. 三峡库区消落带不同水淹强度下池杉与落羽杉的光合生理特性[J]. 生态学报, 2018, 38(8):121-130. [37] 陈海生, 金连根. 淹水胁迫对水库消落带狗牙根保护酶活性的影响[J]. 内蒙古农业大学学报: 自然科学版, 2014, 35(1):46-48. [38] 李 川, 周 倩, 王大铭, 等. 模拟三峡库区淹水对植物生长及生理生化方面的影响[J]. 西南大学学报: 自然科学版, 2011, 33(10):46-50. [39] 莫荣利, 李 勇, 于 翠, 等. 水分胁迫对桑树生理生化特性的影响[J]. 湖北农业科学, 2017, 56(24)-4820. [40] 张东向, 赫延龄, 郑蔚虹, 等. 植物对SO2反应的研究及其在环境保护中的应用[J]. 高师理科学刊, 1996, 16(2):78-80. [41] 阎秀峰, 李 晶, 祖元刚. 干旱胁迫对红松幼苗保护酶活性及脂质过氧化作用的影响[J]. 生态学报, 1999, 19(6):850-854. doi: 10.3321/j.issn:1000-0933.1999.06.014