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| 翠菊根系养分捕获形态塑性及其生理机制 | |
| 引用本文： | 董佳,牟溥. 翠菊根系养分捕获形态塑性及其生理机制[J]. 植物生态学报, 2012, 36(11): 1172-1183. DOI: 10.3724/SP.J.1258.2012.01172 |
| 作者姓名： | 董佳 牟溥 |
| 作者单位： | 北京师范大学生命科学学院, 生物多样性与生态工程教育部重点实验室, 北京 100875 |
| 摘 要： | 为验证以下3个假设: 1) NO3 -和NH4 +及其不同供给方式显著影响根系生长; 2) NO3 -和NH4 +以及不同供给方式对根内激素含量影响显著; 3)根构型(1级根长、单位2级根上1级侧根密度(分枝强度)和1级根在2级根上的根间距)与根内激素(生长素(IAA)、脱落酸(ABA)和细胞分裂素(玉米素核苷+玉米素) (CK (ZR + Z))含量显著相关, 采用营养液培养方法, 使实验植物翠菊(Callistephus chinensis)在两种氮肥(NO3 -和NH4 +)、不同施氮浓度(NO3 -: 0.2、1.0和18.0 mmol·L -1; NH4 +: 0.2、4.0和20.0 mmol·L -1), 以及脉冲和稳定两种施用方式处理下生长。在处理35天后收获植物, 测定根系生物量、根系构型指标(根系1级根长、单位2级根上1级侧根数和1级根在2级根上的根间距)和根系中激素含量(IAA、ABA和CK (ZR + Z))。结果显示: 1)实验处理对根生物量和根系中IAA、ABA和CK (ZR + Z)含量均有不同程度的显著影响: 施用NH4 +使根生物量和根内IAA含量显著低于施用NO3 -; 高浓度NO3 -和NH4 +处理亦使根生物量和IAA降低; 相对于稳定处理, 脉冲施氮显著降低根生物量和根内IAA含量; NO3 -使根内CK (ZR + Z)含量显著高于施用NH4 +, 且与施氮浓度及施氮方式无关; NO3 -处理下, 高浓度使根内ABA含量提高, 且脉冲处理使ABA含量升高。NH4 +处理下, 高浓度使根内ABA含量降低, 而施氮方式对其没有显著影响。2)根构型因素与根内激素关系各异: 各激素与1级根间距无显著关系; IAA和CK (ZR + Z)与1级根长和侧根密度有显著回归关系。3)根构型因素与根生物量的关系是根生物量与1级根长和侧根密度有显著正回归关系, 与1级根间距无显著回归关系。实验结果表明翠菊根生长的 “反常”可能是由于其对脉冲高浓度NH4 +耐受阈值低所致。该研究通过实验建立了氮养分种类/供应方式通过改变激素、影响根构型而影响根生长的联系, 进一步探究了植物根养分捕获塑性机制。 |
| 关 键 词： | 翠菊 施氮处理 根构型 根生物量 根激素 |
| 收稿时间： | 2012-04-25 |
| 修稿时间： | 2012-07-23 |
Root nutrient foraging of morphological plasticity and physiological mechanism in Callistephus chinensis |
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| DONG Jia , MOU Pu. Root nutrient foraging of morphological plasticity and physiological mechanism in Callistephus chinensis[J]. Acta Phytoecologica Sinica, 2012, 36(11): 1172-1183. DOI: 10.3724/SP.J.1258.2012.01172 | |
| Authors: | DONG Jia MOU Pu |
| Affiliation: | Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, China |
| Abstract: | Aims Previous studies discovered unusual plasticity in root growth of Callistephus chinensis, in that fewer fine roots grow in pulse soil nutrient patches than in unfertilized patches. Our goal is to interpret this event via experimentation following the theory of plant physiological ecology. The experiment tested the following hypotheses: NO3–, NH4+ and method of application 1) significantly affect root growth and 2) significantly affect root hormones and 3) root hormones (auxin (IAA), abscisic acid (ABA), and cytokinin (zeatin riboside + zeatin) (CK (ZR + Z))) significantly affect root architecture (indicated by the length of the 1st order fine roots, the inter 1st order root length and the density of the 1st order fine lateral roots). Methods The water culture approach was employed with treatments of two fertilizers (NO3– and NH4+), two methods of application (stable vs. pulse, i.e., pulse shift to high N concentration from low and mid concentration) and low, mid and high concentrations of the fertilizers (NO3–: 0.2, 1.0 and 18.0 mmol·L–1; NH4+: 0.2, 4.0 and 20.0 mmol·L–1). The experiment lasted 35 days after the treatments, the plants were harvested by the end of the experiment and all concerned parameters were measured including root mass, the above-mentioned root architecture parameters and the contents of root hormones. Important findings The experimental treatments affected root mass and root hormones with different significances. The high concentrations of NO3– and NH4+ both greatly lowered the root mass and IAA. Values were lower in the NH4+ culture than in the NO3– one. Pulse shift treatment lowered both further. CK (ZR + Z) contents did not respond to the concentrations and the methods of application, but to NO3– or NH4+; the latter led much lower CK (ZR + Z) contents than the former. Root mass had positive regression relationships with 1st order root length and the density of the fine lateral roots, had a linear regression relationship with IAA, a negative exponential relationship with CK (ZR + Z) and complicated relationships with ABA. The different hormones had different relationships with the root architecture parameters. They were all irrelevant with 1st order inter-root length, ABA had relationships with 1st order lateral root density only and IAA and CK (ZR + Z) both had significant regression relationships with 1st order root length and 1st order lateral root density. The results established physio-ecological path relationships of heterogeneous nutrient stimulation→changes in root hormone contents→changes in root architecture→root plastic growth. As to the unusual root growth of C. chinensis, we infer that the species had very low tolerance to temporal variation in the N environment, particularly NH4+. |
| Keywords: | Callistephus chinensis nitrogen treatment root architecture root biomass root hormone |
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