Prediction of Photosynthetic Carbon Assimilation Rate of Individual Rice Leaves under Changes in Light Environment Using BLSTM-Augmented LSTM

A model to predict photosynthetic carbon assimilation rate(A)with high accuracy is important for forecasting crop yield and productivity.Long short-term memory(LSTM),a neural network suitable for time-series data,enables prediction with high accuracy but requires mesophyll variables.In addition,for practical use,it is desirable to have a technique that can predict A from easily available information.In this study,we propose a BLSTM augmented LSTM(BALSTM)model,which utilizes bi-directional LSTM(BLSTM)to indirectly reproduce the mesophyll variables required for LSTM.The most significant feature of the proposed model is that its hybrid architecture uses only three relatively easy-to-collect external environmental variables—photosynthetic photon flux density(Q_(in)),ambient CO_(2) concentration(C_(a)),and temperature(T_(air))—to generate mesophyll CO_(2) concentration(C_(i))and stomatal conductance to water vapor(g_(sw))as intermediate outputs.Then,A is predicted by applying the obtained intermediate outputs to the learning model.Accordingly,in this study,1)BALSTM(Q_(in),C_(a),T_(air))had a significantly higher A prediction accuracy than LSTM(Q_(in),C_(a),T_(air))in case of using only Q_(in),C_(a),and T_(air);2)BALSTMC_(i),g_(sw),which had C_(i) and g_(sw) as intermediate products,had the highest A prediction accuracy compared with other candidates;and 3)for samples where LSTM(Q_(in),C_(a),T_(air))had poor prediction accuracy,BALSTMC_(i),g_(sw)(Q_(in),C_(a),T_(air))clearly improved the results.However,it was found that incorrect predictions may be formed when certain factors are not reflected in the data(e.g.,timing,cultivar,and growth stage)or when the training data distribution that accounts for these factors differs from the predicted data distribution.Therefore,a robust model should be constructed in the future to improve the prediction accuracy of A by conducting gasexchange measurements(including a wide range of external environmental values)and by increasing the number of training data samples.

IN-LINE MEASUREMENT OF PARTICLE SIZE AND CONCENTRATION WITH LIGHT FLUCTUATION METHOD

This paper presents a new method for in-line and in-situ particle sizing based on the Light Fluctuation Method, including the development of a novel optical probe capable of measuring particle size and concentration in the broad range of 10~1000 microns.

A novel light fluctuation spectrum method for in-line particle sizing

This paper discusses two problems in in-line particle sizing when using light fluctuation method. First, by retrieving the ratio of particle concentrations at different time, the intensity of incident light is obtained. There exists narrow error between the calculated and pre-detected value of the intensity of incident light. Secondly, by combining spectrum analysis with Gregory＇s theory, a multi-sub-size zone model is proposed, with which the relationship between the distribution of turbidity and the particle size distribution （PSD） can be established, and an algorithm developed to determine the distribution of turbidity. Experiments conducted in the laboratory indicate that the measured size distribution of pulverized coal conforms well with the imaging result.

Plants response to light stress

Plants require solar energy to grow through oxygenic photosynthesis;however,when light intensity exceeds the optimal range for photosynthesis,it causes abiotic stress and physiological damage in plants.In response to high light stress,plants initiate a series of signal transduction from chloroplasts to whole cells and from locally stressed tissues to the rest of the plant body.These signals trigger a variety of physiological and biochemical reactions intended to mitigate the deleterious effects of high light intensity,such as photodamage and photoinhibition.Light stress protection mechanisms include chloroplastic Reactive oxygen species(ROS)scavenging,chloroplast and stomatal movement,and anthocyanin production.Photosynthetic apparatuses,being the direct targets of photodamage,have also developed various acclimation processes such as thermal energy dissipation through nonphotochemical quenching(NPQ),photorepair of Photosystem II(PSII),and transcriptional regulation of photosynthetic proteins.Fluctuating light is another mild but persistent type of light stress in nature,which unfortunately has been poorly investigated.Current studies,however,suggest that state transitions and cyclic electron transport are the main adaptive mechanisms for mediating fiuctuating light stress in plants.Here,we review the current breadth of knowledge regarding physiological and biochemical responses to both high light stress and fiuctuating light stress.

A Novel Method for Measuring the Coarse Water Droplets in Wet Steam Flow in Steam Turbines

Some optical probes based on light extinction have been developed to measure wetness dominated with fine droplets in steam turbine. However, coarse water droplets (hereafter referred to as CWD) that are the main cause of erosion of blade and of wetness loss of steam turbine can’t be detected by the extinction probes because of its large size. In this paper, a new method - the light fluctuation method is presented that is capable of measuring the she of CWD. A new probe based on this method was developed for measuring the she of CWD as well as its velocity and concentration.

Quantitative proteomics reveals redox-based functional regulation of photosynthesis under fluctuating light in plants

Photosynthesis involves a series of redox reactions and is the major source of reactive oxygen species in plant cells.Fluctuating light(FL) levels,which occur commonly in natural environments,affect photosynthesis;however,little is known about the specific effects of FL on the redox regulation of photosynthesis.Here,we performed global quantitative mapping of the Arabidopsis thaliana cysteine thiol redox proteome under constant light and FL conditions.We identified8857 redox-switched thiols in 4350 proteins,and1501 proteins that are differentially modified depending on light conditions.Notably,proteins related to photosynthesis,especially photosystem I(PSI),are operational thiol-switching hotspots.Exposure of wild-type A.thaliana to FL resulted in decreased PSI abundance,stability,and activity.Interestingly,in response to PSI photodamage,more of the PSI assembly factor PSA3 dynamically switches to the reduced state.Furthermore,the Cys199 and Cys200 sites in PSA3 are necessary for its full function.Moreover,thioredoxin m(Trx m) proteins play roles in redox switching of PSA3,and are required for PSI activity and photosynthesis.This study thus reveals a mechanism for redox-based regulation of PSI under FL,and provides insight into the dynamic acclimation of photosynthesis in a changing environment.