Photosynthetically active radiation distribution in the Zostera noltii Hornemann canopy at various solar altitudes

2021 ◽  
Author(s):  
Alexander V. Prazukin ◽  
Alexandr A. Latushkin ◽  
Yury K. Firsov ◽  
Anna A. Chepyzhenko
Keyword(s):  
Photosynthetically Active Radiation ◽  
Zostera Noltii ◽  
Active Radiation ◽  
Radiation Distribution

Temperature stratification and photosynthetically active radiation distribution in the Zostera noltii Hornemann canopy under shallow water conditions at different solar elevation angles (the Black sea)

2020 ◽  
pp. 160-178
Author(s):  
Александр Васильевич Празукин ◽  
Юрий Константинович Фирсов ◽  
Александр Александрович Латушкин ◽  
Анна Алексеевна Чепыженко
Keyword(s):  
Black Sea ◽  
Photosynthetically Active Radiation ◽  
Light Availability ◽  
Temperature Stratification ◽  
The Black Sea ◽  
Shallow Waters ◽  
Zostera Noltii ◽  
Active Radiation ◽  
Solar Elevation ◽  
Radiation Distribution

Морские травы экологически важны, но чрезвычайно уязвимы перед антропогенными изменениями в прибрежных зонах, которые влияют на доступность света в этих экосистемах. При разной высоте Солнца над горизонтом в зондирующем режиме проводилось одновременное измерение значений температуры воды и интенсивности фотосинтетически активной радиации (IPAR) по профилю полога Zostera noltii Hornemann (высота полога 32 см.) в мелководной части Казачьей бухты (г. Севастополь, Черное море, 44°57′26″ с.ш., 33°40′33″ в.д.). Для полога Z. noltii характерен одномодальный тип вертикального распределения биомассы с максимумом (65,7 г (сухой массы) / м2) в его нижней части. Рассматривается изменение температурной стратификации и распределения IPAR по профилю растительного полога Z. noltii в течение светового дня. Seagrass is environmentally significant but extremely vulnerable in coastal areas to anthropogenic changes, which affect light availability. Simultaneous measurements of water temperature and photosynthetically active radiation (PAR) intensity in the sounding mode were taken at different solar elevation angles for the Zostera noltii Hornemann canopy (canopy height 32 cm) in shallow waters of the Cossack Bay (Sevastopol, the Black Sea, 44°57′26″ с.ш., 33°40′33″ в.д.). Z. noltii canopy is characterized by a unimodal type of biomass vertical distribution with its maximum (65,7 g (dry matter)/m2) in the lower part. Temperature stratification and IPAR distribution changes within the Z. noltii vegetation canopy profile during daylight hours are considered.

Estimating photosynthetically active radiation distribution in maize canopies by a three-dimensional incident radiation model

2008 ◽  
Vol 35 (10) ◽  
pp. 867 ◽  
Author(s):  
Xiping Wang ◽  
Yan Guo ◽  
Xiyong Wang ◽  
Yuntao Ma ◽  
Baoguo Li
Keyword(s):  
Photosynthetically Active Radiation ◽  
Three Dimensional ◽  
Incident Radiation ◽  
Parallel Projection ◽  
Central Projection ◽  
Plant Canopy ◽  
Radiation Model ◽  
Area Index ◽  
Active Radiation ◽  
Radiation Distribution

The three-dimensional (3-D) radiation distribution model in plant canopy is pivotal for understanding and modelling plant eco-physiological processes. Diffuse and direct radiations penetrate into plant canopies in different ways and may present different intensity and wavelength composition. Sunfleck (the canopy surfaces where the direct radiation reaches) distribution in the plant canopy is usually regarded as an important index for crop development, especially under dense canopy conditions. Distributions of direct and diffuse components of photosynthetically active radiation (PAR) in maize (Zea mays L.) canopies were estimated respectively using a 3-D incident radiation model (3DIRM). The 3DIRM model was set up for computing incident radiation in crop canopies by applying a parallel-projection based submodel for direct solar radiation and a central-projection based submodel for incident diffuse radiation simulation in crop canopy. It was well assessed with a field experiment with multi-point PAR measurement in maize canopies with relative errors of 2.6, 4.5 and 2.6%, respectively, for sunfleck area ratio, diffuse PAR and total PAR. The results suggest that the 3DIRM model could be used to estimate the direct, diffuse and total PAR at any specific surface part in the 3-D canopy space. The exponential distinction model for direct, diffuse and total PAR along with leaf area index in different heights in maize canopies was also evaluated based on the 3DIRM simulation results.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

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