The Effect of High Temperature after Anthesis on Rice Quality and Starch Granule Structure of Endosperm

To ascertain the effect mechanism of high temperature after anthesis on rice quality, the experiment was conducted with two rice lines, the heat-tolerant line 996 and heat-sensitive line 4628, with high temperature and optimal temperature in the growth chamber to investigate the effect of high temperature stress after anthesis on rice appearance quality, milling quality, cooking and eating quality and starch granule structure of endo- sperm. The result showed that milled rice rate, head rice rate, amylose content and gel consistency of both lines decreased under high temperature stress after anthesis, while the ratio of grain length to width, chalky rate, chalkiness, protein content increased. Under high temperature treatments, gelatinization temperature, final viscosity, set back and peak time increased, breakdown decreased, Mg content and K content increased, Mg/K ra- tio decreased. Under same treatment, the extent of rice quality of heat tolerant line 996 affected by high temperature was lower than that of heat sensitive line 4628. Under high temperature stress after anthesis, starch granule arranged untightly, most of starch granules existed in the form of a single starch endosperm, refractive index decreased, transparency reduced, and led to the formation of chalk. Under high temperature stress af- ter anthesis, the increase of protein content, the decrease of Mg/K, the changes of rice RVA profile characteristics and starch granule structure of endosperm could be the main reason for the decrease of rice cooking and eating quality and appearance quality.

Influence of Anthesis Date and Boll Branch Position on Qualities and Super-molecular Structure of Cotton Fiber

The influences of the anthesis date and the fruiting branch positions on parameters of cotton fiber quality and super-molecular structure were studied. Fiber quality parameters, such as cotton fiber length, micronair, maturity and fiber strength deteriorated with postponing the anthesis date and decreasing temperature. When anthesis happened on the same date, the fruiting branch positions affected the fiber quality parameters, and the fiber quality parameters of the lower portion turned out to be higher than that of the upper portion, although the difference was insignificant. The super-molecular structure of the lower portion turned out to be superior to that of the upper portion at the early anthesis date and high temperature, which is in accordance with what was mentioned above, but the fruiting branch positions did not affect the impact of the anthesis date on the super-molecular structure.

Classification of oil palm female inflorescences anthesis stages using machine learning approaches

Prediction of pollination stages in oil palm plantations is an important research area in precision agriculture.Oil palm is known as the most efficient commercial crop with the capacity to fulfill the growing global demand for vegetable oil consumption.However,oil palm production dependence on pollination is experiencing issues with decreasing the actual yield.Consequently,alternative methods in commercial plantations such as humanassisted pollination and recently Wireless Sensor Network(WSN)have been deployed despite their high economic costs due to labor requirements.Oil palm assisted pollination requires precision,inspection,traceability,and validation processes in the field.Currently,all these processes are performed by humans that can be associated with false assumptions,uncertainty,and pollination latency.Therefore,Machine Learning(ML)approaches as a subset of the Artificial Intelligence(AI)domain provides efficient,cost-effective,and non-destructive solutions to determine these reproductive stages for future autonomous pollination system.Our goal was to reduce the variability of worker’s performance in oil palms,using ML algorithms to make expert decisions and reduce the risk related to a transient workforce.This comparative empirical study examined and compared the performance of the Random Forest(RF)against k Nearest Neighbor(kNN)and Support Vector Machine(SVM)for classification of oil palm pre-anthesis and anthesis stages,dividing into four classes(1,2,3,and 4).These models were tested using thermal features(endogenous)individually and in combination with meteorological variables(exogenous).The performance of models is evaluated with specific measures of performance,such as overall user’s and producer’s accuracies and F-measure values derived from the confusion matrix.The results showed that the RF model produced better results with regard to average Fmeasure(88.6%,71.83%),producer’s accuracies(88.70%,71.35%),and user’s accuracies(88.27%,72.36%)on test sets using exogenous+exogenous and endogenous feature sets,respectively.Among the three classifiers tested with two datasets,the RF method outperforms the other two popular algorithms,i.e.,kNN and SVM with respect to accuracy and F-measure metrics.The results validated the significance of thermal parameters,provided valuable features to devise an intelligent pollination management system,and proved the feasibility of using the RF model for the classification of oil palms four stages of anthesis.

Diversity of Flower Opening Time and Duration in Rice (Oryza sativa ssp. indica) Landraces of South and Southeast Asia in Different Cultivation Seasons

Different cultivars of rice(Oryza sativa)open at different times of the day,and the overlap of anthesis time in rice between the neighbouring cultivars is of crucial importance to the degree of cross pollination in rice.Nevertheless,none of the past experiments with cross pollination between different rice cultivars ever reported the respective flower opening time(FOT)and flower exposure duration(FED)of the parent cultivars,until recently.The authors present here the first record of FOT and FED of 1114 indica rice landraces of South and Southeast Asia,growing during sum-mer and winter seasons in three consecutive years.The authors also present an analysis of the influences of the grow-ing season on the anthesis behaviour,and present the first records of the FOT and FED variability on sunny and cloudy days of a large number of landraces.The data show that rice florets tend to open later in the morning(that is,take longer time to anthesis after sunrise)on sunny days than on cloudy days,and also significantly later during long day seasons(spring and summer)than during short day season(winter);and that FED is inversely related to both FOT and the length of duration from sunrise to first flower opening.The wide ranges of FOT(8:50 a.m.to 12:40 p.m.)and FED(15 to 194 minutes)also suggest the ample time window for receiving pollen from neighbouring cultivars with differ-ent FOT,enhancing the chances of cross pollination between hundreds of rice landraces with FOT and FED overlaps.

新疆特早熟陆地棉纤维细胞发育过程的超微结构观察

利用透射电镜观察新疆特早熟陆地棉新陆早36号纤维发育过程中的超微结构变化。在10DPA纤维细胞初生壁形成期,液泡占据纤维细胞中央,细胞质中有大量的线粒体、内质网、高尔基体等细胞器,初生壁较薄且厚度均匀;在20DPA时,纤维在初生壁内已明显有一层薄薄的次生壁的形成,细胞质中细胞器部分解体;随后次生壁增厚速度逐步加快,在30DPA到40DPA之间,纤维平均增厚速度约为每天0.139m,在40DPA到50DPA之间,纤维平均增厚速度约为每天0.47m。纤维细胞次生壁向内层逐步层层加厚,形成"日生长轮"。随着纤维细胞的脱水成熟,纤维细胞次生壁增厚使纤维中腔只剩下一条窄缝。观察结果表明,虽然特早熟陆地棉发育进程快,开花早,但纤维细胞的发育进程与所报道的其它棉花品种具有相似性。

Effects of Humic Acid and Crop Residues on Soil and Wheat Nitrogen Contents

This study was conducted with the aim of finding humic acid and crop residues effects on soil and wheat nitrogen at New Development Farm, University of Agriculture, Peshawar, Pakistan during winter 2009-2010. The experiment was laid out in RCB design having four replications. Different levels (1, 1.5, 2 and 2.5 kg ha-1) of Humic acid were applied at sowing time. Mungbean (5 tons ha-1), wheat straw (10 tons ha-1) and mungbean (2.5 tons ha-1) + wheat straw (5 tons ha-1) were incorporated 30 days before sowing. Our results showed higher mineral and total nitrogen (7.32 and 0.43, respectively) mg kg-1 in soil and also higher nitrogen in stem, leaves and grains (2.3, 4.6 and 21.1, respectively) mg kg-1 at maturity in those plots in which 2.5 kg ha-1 of humic acid was applied. Higher mineral and total nitrogen (7.04 and 0.5, respectively) mg kg-1 in soil and also higher nitrogen in leaves (5.5) mg kg-1 at pre-anthesis, while at maturity stage in stem, leaves and grain (5.5, 2.1, 4.2 and 20.8) g kg-1 was recorded in those plots in which 5 tons ha-1 mung bean was incorporated. Our experimental results suggest the use of 5 tons ha-1 of mungbean residues with 2.5 kg ha-1 of humic acid to improve soil fertility availability of more nitrogen in wheat plants to increase the crop yield and grains quality.

Impacts of climate warming and crop management on maize phenology in northern China

Climate warming has and will continue to exert a significantly impact on crop phenology in the past and coming decades.Combining observed data of phenology and a crop growth model provides a good approach for quantitating the effects of climate warming and crop management on crop phenology.The purpose of this study is to determine the impacts of temperature change, sowing date(SD) adjustment and cultivar shift on maize phenology in northern China during 1981–2010.Results indicated that climate warming caused anthesis date(AD) and maturity date(MD) of maize to advance by 0.2-5.5 and 0.6-11.1 d/10 a, respectively.Due to climate-driven changes in maize phenology, three growth periods of maize, i.e., vegetative growth period(VGP;from sowing to anthesis), reproductive growth period(RGP;from anthesis to maturity) and whole growth period(WGP;from sowing to maturity) shortened by 0.2-5.5, 0.4-5.6 and 0.6-11.1 d/10 a, respectively.With SD adjustment(i.e., SD advancement), AD and MD occurred early by 0.5-2.6 and 0.1-3.4 d/10 a, respectively.SD adjustment caused duration of VGP of maize to prolong.However, duration of RGP slightly shortened by 0.1-1.3 d/10 a.Furthermore, due to cultivar shift, MD of maize significantly delayed by 4.9-12.2 d/10 a.Durations of VGP, RGP and WGP of maize prolonged by 0.2-4.1, 1.6-8.4 and 4.3-11.8 d/10 a, respectively.In conclusion, our results indicated that cultivar shift, to some extent, could mitigate the negative impact of climate warming on maize phenology.

Poor development of spike differentiation triggered by lower photosynthesis and carbon partitioning reduces summer maize yield after waterlogging

Stable yield of staple grains must be ensured to satisfy food demands for daily dietary energy requirements against the backdrop of global climate change. Summer maize, a staple crop, suffers severe yield losses due to extreme rainfall events, threatening food security. A randomized block experiment with four treatments: control, no water stress(CK);waterlogging for 6 days at the third leaf, sixth leaf stage,and 10 th day after tasseling, was conducted to investigate the mechanism of waterlogging-induced yield losses of summer maize. Waterlogging delayed plant growth and impaired tassel and ear differentiation,leading to high grain yield losses of Denghai 605(DH605). Waterlogging at third leaf(V3) stage reduced the photosynthesis of DH605, reducing total dry matter weight. Waterlogging at V3 stage reduced sucrose-cleaving enzymes activities in spike nodes and ears, reducing the carbon partitioned to ears(–53.1%), shanks(–46.5%), and ear nodes(–71.5%) but increasing the carbon partitioned to ear leaves(9.6%) and tassels(43.9%) in comparison with CK. The reductions in total carbon assimilate together with the reduced carbon partitioning to ears resulted in poor development of spikes(with respectively 15.2%and 20.6% reductions in total florets and fertilized florets) and lengthened the anthesis–silking interval by around 1 day, leading to high yield losses.

Role of endogenous hormones,glumes,endosperm and temperature on germination of Leymus chinensis(Poaceae)seeds during development

Aims Leymus chinensis is an original dominant plant in the Songnen grassland,and it has great value for restoration of severely degraded land.However,seeds are dormant,and low germination percentage is a problem for restoring L.chinensis grassland.The mechanism of seed dormancy is not been well understood.The primary aims of the present study were to investigate the dormancy mechanism of L.chinensis seeds(caryopses)with reference to the role of embryo-covering layers,endogenous hormones and temperature.Methods Changes in concentration of the endogenous hormones GA3,indoleacetic acid(IAA),zeatin riboside(ZR)and abscisic acid(ABA)in L.chinensis seeds fromanthesis to maturity weremeasured by the enzymelinked immunosorbent assay method.Germination at different stages of maturity were tested at 16/28
C,5/28
C and 5/35
C for intact seeds with glumes(control),intact seeds with glumes removed(nakedwhole seeds)and intact seeds with glumes and one-half of the endosperm removed(naked-half seeds).Important Findings Of the four endogenous hormones monitored,only the concentration of ZR differed significantly between the beginning and the end of seed development(increased);the GA3/ABA ratio also did not differ.Rank of germination percentage of control at the three temperature regimens was 5/28
C>16/28
C>5/35
C.Germination percentage of the naked-half seeds reached 100%under the three temperature regimens.We concluded that dormancy of L.chinensis seeds is not mainly controlled by endogenous hormones.Germination temperature,mechanical resistance of glumes and inhibition of endosperm are the main factors controlling dormancy and germination of L.chinensis seeds.