Regulation of 2-acetyl-1-pyrroline and grain quality in early-season indica fragrant rice by nitrogen and silicon fertilization under different plantation methods

Fragrant rice has a high market value,and it is a popular rice type among consumers owing to its pleasant flavor.Plantation methods,nitrogen(N)fertilizers,and silicon(Si)fertilizers can affect the grain yield and fragrance of fragrant rice.However,the core commercial rice production attributes,namely the head rice yield(HRY)and 2-acetyl-1-pyrroline(2-AP)content of fragrant rice,under various nitrogen and silicon(N-Si)fertilization levels and different plantation methods remain unknown.The field experiment in this study was performed in the early seasons of 2018 and 2019 with two popular indica fragrant rice cultivars(Yuxiangyouzhan and Xiangyaxiangzhan).They were grown under six N-Si fertilization treatments(combinations of two levels of Si fertilizer,0 kg Si ha^(−1)(Si0)and 150 kg Si ha^(−1)(Si1),and three levels of N fertilizer,0 kg N ha^(−1)(N0),150 kg N ha^(−1)(N1),and 220 kg N ha^(−1)(N2))and three plantation methods(artificial transplanting(AT),mechanical transplanting(MT),and mechanical direct-seeding(MD)).The results showed that the N-Si fertilization treatments and all the plantation methods significantly affected the HRY and 2-AP content and related parameters of the two different fragrant rice cultivars.Compared with the Si0N0 treatment,the N-Si fertilization treatments resulted in higher HRY and 2-AP contents.The rates of brown rice,milled rice,head rice,and chalky rice of the fragrant rice also improved with the N-Si fertilization treatments.The N-Si fertilization treatments increased the activities of N metabolism enzymes and the accumulation of N and Si in various parts of the fragrant rice,and affected their antioxidant response parameters.The key parameters for the HRY and 2-AP content were assessed by redundancy analysis.Furthermore,the structural equation model revealed that the Si and N accumulation levels indirectly affected the HRY by affecting the N metabolism enzyme activity,N use efficiency,and grain quality of fragrant rice.Moreover,high N and Si accumulation directly promoted the 2-AP content or affected the antioxidant response parameters and indirectly regulated 2-AP synthesis.The interactions of the MT method with the N-Si fertilization treatments varied in the fragrant rice cultivars in terms of the HRY and 2-AP content,whereas the MD method was beneficial to the 2-AP content in both fragrant rice cultivars under the N-Si fertilization treatments.

Study on a Bowl-based Mechanism for Transplanting Potted Strawberry Seedlings

To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.

Optimization design and experiment of the variable differential gear train planting mechanism

In order to improve the adaptability of the planting mechanism for different plant spacings,a variable differential gear train planting mechanism based on precise pose and trajectory control was proposed by combining the open chain 2R rod group and the variable differential gear train.According to the pose requirements of receiving seedling point,transporting seedling point and planting point,three precise pose points of constrained planting trajectory were determined.Through the three-position motion generation structural synthesis method,combined with computer-aided optimization design software,a set of mechanism parameters that meet the planting requirements were optimized.Based on the optimized mechanism parameters,by only changing the coordinates of two trajectory shape control points,three planting trajectories with key point position information adapted to 300 mm,400 mm and 500 mm plant spacing were obtained by interpolation,and three pairs of total transmission ratio of three groups of variable differential gear trains were calculated.When distributing the total transmission ratio of the mechanism,the fixed axis gear train and the differential gear train are combined.The fixed axis gear train included a pair of non-circular gear pairs and a pair of positive gear pairs,which were convenient for disassembly and assembly.The former drives the sun gear at variable speed,and the latter drives the planet carrier at uniform speed.Based on this structure,the transmission ratio of the positive gear pair is-1,and the transmission ratio of the differential gear train is 0.5.The sub-transmission ratio of the single-stage non-circular gear pair was calculated and the pitch curves of three pairs of noncircular gears were solved.Three pairs of non-circular gear pairs with different transmission ratios were replaced in turn and three sets of planting mechanisms were modeled in three dimensions.The virtual prototype motion simulation was completed by ADAMS software,and the physical prototype was built for vegetable pot seedling planting test.The theoretical solution was consistent with the attitude and trajectory of the actual test.When the test sample size was 100 plants,the actual average plant spacing was measured to be 303 mm,402 mm,and 503 mm,with errors of 1.3%,1.25%,and 1.88%.The width of the moving hole was 72 mm,70 mm,and 71 mm,and the planting success rate were 94%,96%,and 95%.The test results verified the correctness of the optimization design results of the mechanism,indicating that the variable differential gear train planting mechanism can adapt to a variety of plant spacing and has good planting effect.

A Theory of Bio-Quantum Genetics

The physical mechanism of heredity or inheritance of genes is a quantum mechanical and/or quantum computational process. A theory of bio-quantum genetics is established in this paper. Principle of Bio-quantum Genetics is suggested. I propose and define the soft-genes of genetics controlling the processes of heredity or inheritance of genes. This research deals with the quantum mechanisms of Mendel plant heredity and family inheritance as examples of bio-quantum genetics, deepening our understanding of heredity or inheritance. I believe that more contributions will be made to promote researches of bio-quantum genetics or quantum biology at large.

Comparison of yield traits in rice among three mechanized planting methods in a rice-wheat rotation system

Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting （PSMT）, carpet seedling of mechanical transplanting （CSMT） and mechanical direct seeding （MDS） is of great importance not only for rice scientists but also for rice farmers to develop a high-yield production system under mechanical conditions in a rice-wheat rotation system. However, such traits are yet to be studied among rice varieties ofjaponica-indica hybrid rice （JIHR）,japonica conventional rice （JCR） and indica hybrid rice （IHR）. Field experiments were conducted in 2014 and 2015, where six cultivars of the three rice types JIHR, JCR and IHR were grown individually with PSMT, CSMT and MDS methods, under respective managements for each method to achieve the maximum attainable yield. Results showed that （i） the PSMT significantly increased grain yield of JIHR by 22.0 and 7.1%, of JCR by 15.6 and 3.7% and of I HR by 22.5 and 7.4%, compared to MDS and CSMT on average across the two years, respectively. The highest yield was produced by the combination of JIHR and PSMT; （ii） high yield under PSMT was mainly attributed to large sink capacity and high-efficient dry matter accumulation. With sufficient panicles per hectare, the increase of spikelet number per panicle, especially the increase in spikelet number of the secondary rachis-branches was determined to be the optimal approach for developing a large sink capacity for rice under PSMT. The optimal tillers development, large leaf area index at heading stage, and high leaf area duration, crop growth rate and net assimilation rate during grain-filling phase could be the cause of sufficient dry matter accumulation for rice under PSMT; （iii） moreover, the PSMT favored plant growth as well as enriched the stems plus sheaths during grain-filling phase, as compared with CSMT and MDS. These results suggest that PSMT may be an alternative approach to increasing grain yield in a rice-wheat rotation system in the lower reaches of the Yangtze River in China.

Ozone disrupts the communication between plants and insects in urban and suburban areas:an updated insight on plant volatiles

Plant-insect interactions are basic components of biodiversity conservation.To attain the international Sustainable Development Goals(SDGs),the interactions in urban and in suburban systems should be better understood to maintain the health of green infrastructure.The role of ground-level ozone(0_(3)) as an environmental stress disrupting interaction webs is presented.Ozone mixing ratios in suburbs are usually higher than in the center of cities and may reduce photosynthetic productivity at a relatively higher degree.Consequently,carbon-based defense capacities of plants may be suppressed by elevated 0_(3) more in the suburbs.However,contrary to this expectation,grazing damages by leaf beetles have been severe in some urban centers in comparison with the suburbs.To explain differences in grazing damages between urban areas and suburbs,the disruption of atmospheric communication signals by elevated 0_(3) via changes in plant-regulated biogenic volatile organic compounds and long-chain fatty acids are considered.The ecological roles of plant volatiles and the effects of 0_(3) from both a chemical and a biological perspective are presented.Ozone-disrupted plant volatiles should be considered to explain herbivory phenomena in urban and suburban systems.

Temperature and solar radiation utilization of rice for yield formation with different mechanized planting methods in the lower reaches of the Yangtze River,China

Several studies have demonstrated the effect of planting methods on rice yield, but information on the climate resources is limited. This study aims to reveal the effects of planting methods on climate resources associated with rice yield in a rice-wheat rotation system in the lower reaches of the Yangtze River, China. Field experiments were conducted in 2014 and 2015 with two japonica, two indica hybrid, and two japonica-indica hybrid varieties grown under three mechanized planting methods： carpet seedling of mechanical transplanting（CT）, mechanical direct seeding（DS）, and pot-hole seedling of mechanical transplanting（PT）. The rice yield and total dry matter under PT were greater than those under CT and DS methods. Besides, the entire growth duration and daily production showed significant positive relations with rice yield. Compared with CT and DS, the effective accumulated temperature and cumulative solar radiation of rice under PT were higher in phenological phases. In addition, the dry matter/effective accumulated temperature and solar energy utilization of rice under CT and DS were higher during vegetative phase and lower during reproductive and grain filling phases in contrast to PT. The mean daily temperature and mean daily solar radiation in the entire growth duration showed significant positive correlation with rice yield, total dry matter, and harvest index. This study demonstrated that when the mean daily temperature is 〈25.1°C in vegetative phase and 〉20.1°C in grain filling phase, rice yield could be increased by selecting mechanized planting methods. Most varieties under PT method exhibited high yield and climate resources use efficiency compared with CT and DS. In conclusion, the PT method could be a better cultivation measure for high rice yield, accompanied with high temperature and solar radiation use efficiency in a rice-wheat rotation system in the lower reaches of the Yangtze River, China.

Nanoparticle-immersed paper imprinting mass spectrometry imaging reveals uptake and translocation mechanism of pesticides in plants

Design and discovery of carrier-mediated modified pesticides are vital for reducing pesticide dosage and increasing utilization,yet it remains a great challenge due to limited insights into plant translocation mechanisms.Nanostructure/nanoparticle assisted laser desorption/ionization strategy has established itself as a preferential analytical tool for biological tissue analysis,whereas potential applications in plant sciences are hindered with regard to the inability to slice plant leaves and petals.Herein,we report gold nanoparticle(AuNP)-immersed paper imprinting mass spectrometry imaging(MSI)for the spatiotemporal visualization of pesticide translocation in plant leaves.This approach plays a dual role in preserving spatial information and improving ionization efficiency for pesticides regardless of imaging artifacts due to homogenous AuNP deposition.Using this MSI platform,we proposed the elaborate plant translocation mechanism of agrochemicals for the first time,which is currently poorly understood.The dynamic processes of carrier-mediated pesticides can be clearly visualized,including crossing of plasma membranes by transporters,translocation downward in stems through the phloem,diffusion to the xylem and,conversely,accumulation at margins of the treated leaves.Moreover,this AuNP-assisted paper imprinting method could be highly compatible with laser-based MSI instruments,expediting researches across a broad range of fields,especially in nanomaterial development and life sciences.

Molecular mechanisms governing plant responses to high temperatures

The increased prevalence of high temperatures （HTs） around the world is a major global concern, as they dramatically affect agronomic productivity. Upon HT exposure, plants sense the temperature change and initiate cellular and metabolic responses that enable them to adapt to their new environmental conditions.Decoding the mechanisms by which plants cope with HT will facilitate the development of molecular markers to enable the production of plants with improved thermotolerance. In recent decades, genetic, physiological, molecular, and biochemical studies have revealed a number of vital cellular components and processes involved in thermoresponsive growth and the acquisition of thermo- tolerance in plants. This review summarizes the major mechanisms involved in plant HT responses, with a special focus on recent discoveries related to plant thermosensing, heat stress signaling, and HT-regulated gene expression networks that promote plant adaptation to elevated environmental temperatures.

Middle Cretaceous pCO_2 Variation in Yumen, Gansu Province and its Response to the Climate Events

The palaeo-atmospheric CO2 concentration （pCOz） variation in the Yumen, Gansu Province during the middle Cretaceous has been reconstructed using the newly established plant photosynthetic gas exchange mechanistic model, and the results show that the pCO2 values are in the range of about 550 -808 ppmv. The present pCO2 values are higher than the pCO2 results （531-641 ppmv） of the previous study according to the Recent standardization of the stomatal ratio method, and much lower than the pCO2 results （882-1060 ppmv） according to the Carboniferous standardization of the stomatal ratio method. The present pCOz variation is not only within the error range of GEOCARB II and GEOCARB Ill but also is similar to the reconstructed results based on the biochemistry and carbon isotope models. Besides, the present Brachyphyllum specimens were collected from four consecutive horizons of the upper Zhonggou Formation of the Hanxia Section, and the reconstructed pCO2 exhibits the reconstructed pCO2 exhibits a decline trend during the late Aptian to early Albian. This decline variation is probably associated with the Oceanic Anoxic Events （OAElb） and the Cold snap event. With the combination of pCO2 during the Albian to Cenomanian recovered by the plant photosynthetic gas exchange mechanistic model, the pCO2 showed a prominent increase during the late Aptian to early Cenominian, which indicates a response to the greenhouse warming during the middle Cretaceous. Therefore, the mechanical model of the plant photosynthetic gas exchange shows a relatively strong accuracy in the reconstruction of thepCO2 and can reflect a strong relation between the atmospheric CO2 concentrations and climatic events.

Assembly mechanism and energy transfer pathways of plant photosystem II-LHCII supercomplexes discovered through cryo-electron microscopy

Funded by the National Natural Science Foundation of China,Chinese Ministry of Science and Technology,and Chinese Academy of Sciences,ajoint team of three laboratories from the Institute of Biophysics of Chinese Academy of Sciences,namely Liu Zhenfeng’s(柳振峰),Zhang

Design and test of 2ZYM-2 potted vegetable seedlings transplanting machine

In order to improve the efficiency and quality of transplanting vegetables in dry land,based on the seedling technology,transplanting effect and analysis of the planting process,a potted vegetable seedlings transplanting machine was designed.It mainly comprised rotary disc type feeding mechanism,five-bar duckbill type planting mechanism(simulated duckbill mechanism,disc cam,connecting rod,crank,fork,cable)and power transmission system.Based on the physical parameters of the seedlings and design requirements,it was determined that the diameter of the duckbill was D=90 mm,the opening and closing angle was 25°,and the taper angle was 17°.A test bench with adjustable parameters was built by analyzing the structure of the planting mechanism and the motion of the working process.The digital speckle technique was used to optimize the parameters,so that the length of the crankshaftΙwas S1=100 mm,the length of the crankshaftΙΙwas S2=80 mm,the length of the connecting rodΙwas S3=140 mm,the length of the connecting rodΙΙwas S4=260 mm,the length of rod to connecting the rack was S6=314 mm,and the height of planting track was H=450 mm.According to the above parameters and the control requirements of the duckbill mechanism,the cam stroke was determined to be S=15 mm.And the initial phase difference between the two cams was 180°.The experiment was carried out with pepper seedlings as transplanting objects.The results showed that when the planting frequency was 50-70 plants/min,the seedling upright rate was 93%-91.1%,the planting depth qualified rate was 96%-92%.The leakage rate was 0-0.26%,the variation coefficient of plant spacing was 0.37%-0.67%,the injury rate was 0%,and the mechanical damage degree of the mining surface was 2.43-3.77 mm/m2.The machine can effectively improve the quality of transplanting,which can meet the production needs and design requirements of the mechanism.

Design and test of 2ZLX-2 transplanting machine for oil peony

In order to improve the quality of oil peony transplanting,based on the characteristics of peony seedlings and the transplanting effect,the transplanting process was analyzed.A peony seedling transplanting machine was designed,which was mainly composed of a chain-clamp type planting mechanism(clamp,transmission chain,sprocket),slideway,profiling wheels,trencher,the power transmission system and rack.Through the movement analysis of the planting mechanism and its operation process,its structural parameters were optimized.The effective length of the clamp was determined as L_(1)=235 mm,the adjustment range was 235-285 mm,and the height of the planting trajectory was H=340 mm.Based on the physical characteristics and mechanical characteristics of the peony seedlings,the parameters of the slideway and the putter were determined.The effective length of the slideway was determined as L_(2)=420 cm,the width T_(2)=105 mm,the distance between the slideways S=45 mm.The initial angle difference of the putter wasθ=13°,and the putter rotation angleβ=37°,putter height ratioε=2.Based on the above parameters and design requirements,the radius of the planting sprocket R_(1)=42 mm,R_(2)=80 mm.“Feng Dan”peony seedlings were used as transplantation test objects.The results showed that:when the planting frequency was 60-75 plants/min,the upright rate was 89.2%-92.8%,the leakage rate was 0-0.28%,the injury rate of seedlings was 0,and the qualified rate of planting depth was 91.7%-95.3%,the variation coefficient of plant spacing was 0.25%-0.54%.This machine can effectively improve the quality and efficiency of transplanting,meeting the requirements of mechanical design and production needs.

Critical equation of seedling block falling off in transplanting process and the optimization experiment of rape blanket seedling transplanter

Considering both high efficiency and high seedling standing quality is a significant objective for crop mechanized transplanting.Rape blanket seedling transplanting is an innovative and efficient transplanting technique.However,falling off phenomenon has become a common problem facing rape blanket seedling transplanting fields that causes seedling standing quality decrease and restricts crop growth.In this study,the rape blanket seedling of Ningza-1838 varieties and 35 d of seedling age was taken as the research object.The critical falling off equations of seedling was established by dynamic analysis.Main factors affecting seedling falling off were obtained.The critical value of each factor was calculated which were as follows:the rotation speed of the planting mechanism was 24.6 rad/s,the substrate moisture content was 50.4%and the longitudinal picking seedling quantity was 14.7 mm.Taking the seedling falling off rate as evaluation index,the measured critical value of seedling falling off was determined by high speed photography experiment.Under the condition that substrate moisture content was 55%and the longitudinal seedling quantity was 15 mm,the seedling falling off rate sharply increased when the transplanting mechanism rotation speed was increased from 24 rad/s to 26 rad/s.Under the condition that the rotation speed was 22 rad/s and the longitudinal picking seedling quantity was 15 mm,the seedling falling off rate rapidly decreased when the moisture content was increased from 47%to 53%.When moisture content exceeded 53%,this exhibited no obvious change.Under the condition that the moisture content was 50%and the rotation speed was 22 rad/s,the seedling falling off rate swiftly raised when the longitudinal picking seedling quantity was increased from 14 mm to 17 mm.The experimental results showed that the seedling falling off rate increased significantly near the critical value.The experimental results showed that the seedling falling off rate changed significantly near the critical value.It proved that the model was correct.Response surface experiments with the Box-Behnken design were conducted to determine the optimal combination parameters,which were as follows:substrate moisture content was 56.24%,planting mechanism rotation speed was 22.04 rad/s,and longitudinal picking seedling quantity was 14.91 mm.At this time,the seedling falling off rate was 1.36%,which ensured that seedlings could be transplanted stably under the carrier of seedling needle.The verification test was conducted,and the working parameters were adjusted according to the optimization results in experiment.The results of verification test were highly consistent with the optimization solution.The present study may provide a theoretical method for improving seedling standing quality of rape blanket seedling,and laid a foundation for the popularization and development of rape carpet seedling transplanting.