Imaging, screening and remote sensing of photosynthetic activity and stress responses
Imaging, screening and remote sensing of photosynthetic activity and stress responses
复制标题
光合活动和胁迫反应的成像、筛选和遥感
DOI：
10.1007/s10265-021-01324-1
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发表时间：
2021
影响因子：
2.8
通讯作者：
Hikosaka Kouki
中科院分区：
文献类型：
--
作者：
Kohzuma Kaori;Sonoike Kintake;Hikosaka Kouki
所有的生命都依赖光合作用。它不仅为光合生物本身提供能量和碳水化合物，还通过食物网为异养生物提供能量和碳水化合物。它也是全球碳循环中最重要的过程之一。提高光合作用是解决人类社会面临的问题的关键。作物管理和培育具有较高光合活性的品种可能有助于提高作物产量，这是满足人口快速增长所必需的。加强陆地生态系统的固碳能力可能是实现低碳经济的有效途径之一。光合测量的空间尺度在目标生物之间差异很大。气体交换法（CO2或O2）是最可靠和最常用的方法。从细胞（或叶绿体）到叶片和个体鳞片，将样品放入同化室或用同化室夹住，并使用红外气体分析仪或O2电极直接测定气体交换。特别地，商业便携式气体交换测量系统甚至可以用于田间的叶片光合作用测定。对于植被尺度，涡度相关方法直接确定植被和大气之间的CO2交换使用红外气体分析仪和风速仪安装在通量塔。但是，这些方法都存在一些不足之处：首先，这些方法大多对目标有一定的影响。例如，叶片气体交换系统需要夹紧目标叶片，这可能物理地损坏叶片。其次，测量通常是耗时的，因为它需要等待系统中的气体交换变得稳定。第三，这些方法很难识别系统中光合活性的异质性。这些缺点是至关重要的，特别是当我们想要在农业田间管理、突变体筛选或育种中识别具有异常光合活性的个体时。此外，随着目标规模的增加，确定其气体交换在技术上变得更加困难。光学观测是评估光合作用的另一种方法，没有上述问题。由于光合机构涉及各种色素分子，每个色素分子都具有独特的吸收光谱，因此植物的反射光谱包含与光合作用相关的各种信息。此外，光系统II（PSII）叶绿素（叶绿素荧光）发出的荧光产量是非常有用的，因为它的变化取决于PSII的状态;它减少时，分配给PSII光化学反应（光化学猝灭）或热耗散增加（非光化学猝灭）的能量。已经开发了各种方法来评估光合作用状态的光学信息，如脉冲振幅调制（PAM）系统和夫琅和费线深度方法。如今，我们可以通过安装在显微镜观测塔、无人机、飞机、卫星等上的相机在各种空间尺度上进行光学观测来获得光合信息。时间尺度也是获得不同信息的重要方面。短期分析有助于了解光合机构的状况。有多种光合作用过程在黑暗中不活跃。
All lives rely on photosynthesis. It provides energy and carbohydrates not only to photosynthetic organisms themselves but also to heterotrophic organisms through the food web. It is also one of the most important processes in global carbon cycling. Improvement of photosynthesis is a key to solving problems that human society faces. Crop management and breeding of cultivars with higher photosynthetic activities may contribute to increasing crop yields, which are needed to meet rapid population growth. Enhancement of carbon sequestration in terrestrial ecosystems may be one of the effective ways for a low-carbon economy. The spatial scale of photosynthetic measurements varies greatly among target organisms. The gas exchange method (CO2 or O2) is the most reliable and frequently used. From cellular (or chloroplast) to leaf and individual scales, samples are put into or clamped with an assimilation chamber, and gas exchange is directly determined with an infrared gas analyzer or O2 electrode. In particular, commercial portable gas exchange measurement systems can be used for leaf photosynthesis determination even in the field. For vegetation scales, the eddy covariance method directly determines CO2 exchange between the vegetation and atmosphere using an infrared gas analyzer and anemometer installed on a flux tower. However, these methods have some shortcomings.First, most of these methods have some influence on the target. For example, the leaf gas exchange system needs to clamp the target leaf, which may physically damage the leaf. Second, the measurement is often time-consuming as it waits for the gas exchange in the system to become stable. Third, such methods hardly identify heterogeneity of photosynthetic activity in the system. Such shortcomings are critical, especially when we want to identify individuals that have unusual photosynthetic activity in agricultural field management, mutant screening, or breeding. Furthermore, as the target scale increases, determining its gas exchange becomes technically more difficult. Optical observations are an alternative method to assess photosynthesis without the problems mentioned above. As the photosynthetic apparatus involves various pigment molecules, each of which has unique absorption spectra, reflectance spectra from plants include various information related to photosynthesis. Furthermore, the yield of fluorescence emitted by photosystem II (PSII) chlorophylls (Chl fluorescence) is very informative because it changes depending on the status of PSII; it decreases when the energy allocation to PSII photochemical reaction (photochemical quenching) or heat dissipation increases (non-photochemical quenching). Various methods have been developed to assess photosynthetic status from optical information, such as the pulseamplitude modulation (PAM) system and the Fraunhofer line depth method. Nowadays, we can obtain photosynthetic information by optical observations at various spatial scales using cameras installed on a microscope observation tower, unmanned aerial vehicle, airplane, satellite, etc. Time scale is also an important aspect of obtaining different information. Short-term analyses are useful to know the status of the photosynthetic apparatus. There are multiple photosynthetic processes that are inactive in the dark.