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氮素输入对呼伦贝尔草甸草原植物群落氮磷化学计量特征的影响 被引量:1
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作者 陈友余 杨国姣 +5 位作者 梁潇洒 丁聪 胡艳宇 杨雁茹 张志委 吕晓涛 《生态学杂志》 CAS CSCD 北大核心 2022年第8期1517-1524,共8页
植物群落水平的养分特征是调控生态系统过程的重要因素。大气氮沉降通过改变植物群落物种组成的种间变化过程和改变植物物种水平养分特征的种内变化过程来影响群落水平养分特征。明确上述两种过程的相对重要性对于预测生态系统功能的变... 植物群落水平的养分特征是调控生态系统过程的重要因素。大气氮沉降通过改变植物群落物种组成的种间变化过程和改变植物物种水平养分特征的种内变化过程来影响群落水平养分特征。明确上述两种过程的相对重要性对于预测生态系统功能的变化具有重要意义。本研究依托野外氮素添加实验,分析了氮素输入对于呼伦贝尔草甸草原群落水平氮磷化学计量特征的影响,并分析了两种过程的相对贡献。结果表明:在0~50 g N·m^(-2)·a^(-1)的氮素输入量梯度上,植物群落组成发生明显变化。所关注的17种植物中,8种植物的氮含量与氮素输入量呈显著正相关,而大多数物种的磷含量和N∶P对氮素输入不敏感。随氮素输入量的增加,植物群落水平的氮含量和N∶P均显著升高,而磷含量则无显著变化。氮素输入所引起的群落水平上植物养分特征的变化主要是由于种内变化过程所导致;其对于氮含量、磷含量和N∶P变化的贡献率分别为75%~99%、61%~91%和97%~100%。研究表明:(1)草甸草原生态系统中植物氮磷化学计量特征对于氮素输入的响应具有较强的物种特异性;(2)尽管植物群落组成与结构对于氮素输入非常敏感,但群落水平上氮磷化学计量特征的改变主要是由少数优势物种的种内水平上养分特征变化所导致的。 展开更多
关键词 群落组成 生态化学计量学 种内变化 氮沉降 半干旱草原
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MRI can reveal metabolic changes in lily bulbs in vivo during dormancy release 被引量:3
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作者 HAN HaoJun YI MingFang 《Science China(Life Sciences)》 SCIE CAS 2012年第11期1002-1006,共5页
The factors influencing dormancy release in lily bulbs strongly affect commercialization success, but the mechanism of dormancy release is still unclear. Magnetic resonance imaging (MRI) can detect changes in morpholo... The factors influencing dormancy release in lily bulbs strongly affect commercialization success, but the mechanism of dormancy release is still unclear. Magnetic resonance imaging (MRI) can detect changes in morphology and water status in a living plant bulb and aid in investigating release factors. To evaluate whether MRI could be used to detect intra-bulb metabolic changes during the dormant period in Oriental Lilies (Lilium 'Sorbonne'), a series of MRI and sugar concentration measurements were performed weekly on bulbs stored for 11 weeks at 4°C. The image quality of intra-bulb structure obtained using T 1-weighted imaging was superior to that obtained using T 2 -weighted imaging and had a higher signal-to-noise ratio (0.97±0.01). Magnetization transfer ratio values for the bud and basal plate declined during the first eight weeks of cold storage (P>0.05), and were well correlated with concentration of soluble sugar in the bud (R 2 =0.95) and basal plate (R 2 =0.93). Thus, MRI can serve as a valuable tool for observation and analysis of dynamic morphological and metabolic changes in vivo during dormancy release. This information is potentially useful as a guide in the improvement of horticultural product quality. 展开更多
关键词 transverse and longitudinal relaxation times magnetization transfer ratio (MTR) soluble sugar magnetic resonanceimaging (MRI) Lilium oriental hybrids dormancy release
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