scholarly journals Varied shoot growth in rice plants across different developmental stages under induced flooding

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Pratyasha Samanta ◽  
Abhra Chakrabarti ◽  
Narottam Dey
Keyword(s):  
Developmental Stages ◽  
Shoot Elongation ◽  
Leaf Sheath ◽  
Growth Stages ◽  
Internodal Length ◽  
Rice Varieties ◽  
Submergence Stress ◽  
Wide Range ◽  
Early Seedling ◽  
Sensitive Line

All the modern high yielding rice varieties precariously respond to flooding, although a number of landraces are tolerant to wide range of flooding with penalty of low yield. Stage-specific flood tolerance experiment was performed at three different conditions for three different growth stages from germination to vegetative stage for five such selected landraces, along with a flood-resistant quiescent variety (FR13A), a sensitive line (IR42), an improved cultivar (Swarna) and one Sub1 loci introgressed improved line (Swarna-Sub1). Different morpho-physiological traits at each stage were observed and genotypes were evaluated by these quantifiable traits to understand their underwater performance. All the studied landraces represented strong seed germination and faster coleoptile elongation than FR13A, Swarna and Swarna-Sub1 under water. At early seedling stage var. Kumrogarh embraced with highest number of seedlings with leaves and extended greater leaf portion above the water. Shoot elongation associated with internodal and petiole/blade elongation and well developed aerenchyma tissue facilitated vegetative tissues to survive. In this stage, Kumrogarh had highest plant height but Bakui had highest internodal length which indicated that kumrogarh might have the greater leaf sheath or blade elongation up to day 21 and also smaller increase (%) in air cavity formation at day 21 which made the stem to be upright devoid of lodging. All these results indicated that the studied landraces are the potential resources for submergence avoiding response for all the stages and should be elaborately investigated for future breeding programme. The rice line kumrogarh may be one of the potent traditional rice which can withstand all sorts of submergence by virtue of all the stage-specific attributes under submergence stress.

scholarly journals Remobilisation and Fate of Sulphur in Indian Mustard (Brassica juncea. L)

Proceedings ◽  
2019 ◽  
Vol 36 (1) ◽  
pp. 26
Author(s):  
Borpatragohain ◽  
King ◽  
Rose ◽  
Liu ◽  
Kretzschmar ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Storage Proteins ◽  
Plant Defence ◽  
Indian Mustard ◽  
Seed Storage ◽  
Seed Storage Proteins ◽  
Cost Effective ◽  
Growth Stages ◽  
Signalling Molecules ◽  
Wide Range

Understanding the basis of sulphur (S) use efficiency in higher S requiring crops such as brassicas can help develop more cost-effective cultivars. Oleriferous brassicas sequester reduced S in the mature seeds mainly as secondary metabolite-glucosinolate (GSL) and seed storage proteins (SSP). Glucosinolates have a wide range of positive aspects in food production, human nutrition and plant defence, and SSPs are a potential source of high quality vegetable proteins for human and livestock consumption. We carried out a developmental S audit to establish the net fluxes of S in two lines of B. juncea mustard where the level of seed GSL differed. We quantified S pools (sulphate, GSL and total S) in different organs at multiple growth stages until maturity. We have established that leaf S components accumulated as primary S sinks at early developmental stages in condiment type B. juncea become remobilised as a secondary S source to meet the demand of GSL as the dominant seed S sink at maturity. Our evidence for S remobilisation from leaves as primary S sink suggests that up or down regulation of signalling molecules which mediate between secondary S sinks and sources may help modulate economically valuable S compounds in brassica seed.

Cold tolerance in rice varieties at different growth stages

2009 ◽  
Vol 60 (4) ◽  
pp. 328 ◽  
Author(s):  
C. Ye ◽  
S. Fukai ◽  
I. Godwin ◽  
R. Reinke ◽  
P. Snell ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cold Tolerance ◽  
High Elevation ◽  
Temperature Tolerance ◽  
Seedling Stage ◽  
Growth Stages ◽  
Rice Varieties ◽  
Low Temperature Tolerance ◽  
Wide Range ◽  
Different Growth Stages

Low temperature is a common production constraint in rice cultivation in temperate zones and high-elevation environments, with the potential to affect growth and development from germination to grain filling. There is a wide range of genotype-based differences in cold tolerance among rice varieties, these differences often reflecting growth conditions in the place of origin, as well as breeding history. However, improving low temperature tolerance of varieties has been difficult, due to a lack of clarity of the genetic basis to low temperature tolerance for different growth stages of the rice plant. Seeds or plants of 17 rice varieties of different origins were exposed to low temperature during germination (15°C), seedling, booting, and flowering stages (18.5°C), to assess their cold tolerance at different growth stages. Low temperature at the germination stage reduced both the percentage and speed of germination. Varieties from China (B55, Banjiemang, and Lijianghegu) and Hungary (HSC55) were more tolerant of low temperature than other varieties. Most of the varieties showed moderate levels of low temperature tolerance during the seedling stage, the exceptions being some varieties from Australia (Pelde, YRL39, and YRM64) and Africa (WAB160 and WAB38), which were susceptible to low temperature at the seedling stage. Low temperature at booting and flowering stages reduced plant growth and caused a significant decline in spikelet fertility. Some varieties from China (B55, Bangjiemang, Lijiangheigu), Japan (Jyoudeki), the USA (M103, M104), and Australia (Quest) were tolerant or moderately tolerant, while the remaining varieties were susceptible or moderately susceptible to low temperature at booting and flowering stages. Three varieties from China (B55, Lijianghegu, Banjiemang) and one from Hungary (HSC55) showed consistent tolerance to low temperature at all growth stages. These varieties are potentially important gene donors for breeding and genetic studies. The cold tolerance of the 17 rice varieties assessed at different growth stages was correlated. Screening for cold tolerance during early growth stages can therefore potentially be an effective way for assessing cold tolerance in breeding programs.

scholarly journals Mechanism of anoxic tolerance in backcross lines developed through Jyothi x Swarna-Sub 1 under submergence stress.

2020 ◽  
Vol 80 (04) ◽  
Author(s):  
Deepa John ◽  
K. S. Shylaraj
Keyword(s):  
Alcohol Dehydrogenase ◽  
Alcoholic Fermentation ◽  
Flash Flood ◽  
Pyruvate Decarboxylase ◽  
Shoot Elongation ◽  
High Survival ◽  
Rice Varieties ◽  
Survival Percentage ◽  
Submergence Stress ◽  
Donor Parent

Rice varieties adapted to flash flood exhibit submergence tolerance by maintaining reduced shoot elongation under submerged conditions. This study focuses on the two main physiological traits leading to flash flood tolerance- high survival percentage with reduced shoot elongation under submergence and increased rate of alcoholic fermentation. Sub1introgressed BC3F2 lines exhibited higher survival percentage with moderate shoot elongation under submergence stress for fourteen days similar to the donor parent Swarna- Sub1. Enzymatic activities of alcohol dehydrogenase and pyruvate decarboxylase were monitored for fourteen days under submergence stress. The developed Sub1 introgressed lines and the donor parent Swarna-Sub1 showed higher rates of alcohol dehydrogenase and pyruvate decarboxylase activities under submergence stress thereby maintaining optimum rates of alcoholic fermentation. The findings of this study confirmed the expression of tolerance mechanism in the Sub1introgressedJyothi Backcross Inbred lines under submergence stress.

scholarly journals Vegetative and reproductive development of Costa Rican weedy rice compared with commercial rice (Oryza sativa)

2007 ◽  
Vol 25 (1) ◽  
pp. 13-23 ◽  
Author(s):  
E. Sánchez-Olquín ◽  
G. Arrieta-Espinoza ◽  
A.M. Espinoza Esquivel
Keyword(s):  
Reproductive Development ◽  
Costa Rican ◽  
Weedy Rice ◽  
Growth Stages ◽  
Rice Varieties ◽  
Growth Increase ◽  
Wide Range ◽  
Time Required ◽  
Reproductive Phases ◽  
Range Of Variation

The variability in the chronology of the vegetative and reproductive development of weedy rice complex has been little studied. However, a field trial was established to study the timing of growth stages of sixteen weedy rice morphotypes and five rice varieties of Costa Rica. Weedy rice presented a wide range of variation for all descriptors among and within morphotypes. Weedy rice was taller than the rice varieties during vegetative phase and showed a growth increase of 14-23 cm every two weeks. Six morphotypes emerged earlier than commercial rice varieties, but no differences where found between samples for the time required for starting tillering. Early emergence of weedy rice morphotypes was not associated with early flowering, thus no correlation was detected between the vegetative and reproductive phases. All weedy rice morphotypes reached anthesis and maturity earlier than the rice varieties. Nevertheless, varieties Setesa-9 and CR-5272 overlapped anthesis with eleven morphotypes and variety CR-4338 overlapped flowering with eight weedy rice morphotypes. In contrast, none of the morphotypes overlapped anthesis with varieties CR-1821 and CR-1113. The results obtained showed the competitive capacity of weedy rice and provided valuable information about flowering overlap between weedy rice morphotypes and rice varieties which will be useful in the design of gene flow studies among them.

Studies of the relationship between rice stem composition and lodging resistance

2018 ◽  
Vol 156 (3) ◽  
pp. 387-395
Author(s):  
M. Y. Gui ◽  
D. Wang ◽  
H. H. Xiao ◽  
M. Tu ◽  
F. L. Li ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Lignin Content ◽  
Rbf Neural Network ◽  
Morphological Characteristics ◽  
Growth Stages ◽  
Suitable Model ◽  
Prediction Errors ◽  
Lodging Resistance ◽  
Rice Varieties ◽  
Rbf Network

AbstractPlant height and lodging resistance can affect rice yield significantly, but these traits have always conflicted in crop cultivation and breeding. The current study aimed to establish a rapid and accurate plant type evaluation mechanism to provide a basis for breeding tall but lodging-resistant super rice varieties. A comprehensive approach integrating plant anatomy and histochemistry was used to investigate variations in flexural strength (a material property, defined as the stress in a material just before it yields in a flexure test) of the rice stem and the lodging index of 15 rice accessions at different growth stages to understand trends in these parameters and the potential factors influencing them. Rice stem anatomical structure was observed and the lignin content the cell wall was determined at different developmental stages. Three rice lodging evaluation models were established using correlation analysis, multivariate regression and artificial radial basis function (RBF) neural network analysis, and the results were compared to identify the most suitable model for predicting optimal rice plant types. Among the three evaluation methods, the mean residual and relative prediction errors were lowest using the RBF network, indicating that it was highly accurate and robust and could be used to establish a mathematical model of the morphological characteristics and lodging resistance of rice to identify optimal varieties.

scholarly journals A Convolutional Neural Network-Based Method for Corn Stand Counting in the Field

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 507
Author(s):  
Le Wang ◽  
Lirong Xiang ◽  
Lie Tang ◽  
Huanyu Jiang
Keyword(s):  
Frame Rate ◽  
Flying Height ◽  
Battery Life ◽  
Growth Stages ◽  
Camera Motion ◽  
Long Duration ◽  
Manual Counting ◽  
Detection And Counting ◽  
Plant Image ◽  
Early Seedling

Accurate corn stand count in the field at early season is of great interest to corn breeders and plant geneticists. However, the commonly used manual counting method is time consuming, laborious, and prone to error. Nowadays, unmanned aerial vehicles (UAV) tend to be a popular base for plant-image-collecting platforms. However, detecting corn stands in the field is a challenging task, primarily because of camera motion, leaf fluttering caused by wind, shadows of plants caused by direct sunlight, and the complex soil background. As for the UAV system, there are mainly two limitations for early seedling detection and counting. First, flying height cannot ensure a high resolution for small objects. It is especially difficult to detect early corn seedlings at around one week after planting, because the plants are small and difficult to differentiate from the background. Second, the battery life and payload of UAV systems cannot support long-duration online counting work. In this research project, we developed an automated, robust, and high-throughput method for corn stand counting based on color images extracted from video clips. A pipeline developed based on the YoloV3 network and Kalman filter was used to count corn seedlings online. The results demonstrate that our method is accurate and reliable for stand counting, achieving an accuracy of over 98% at growth stages V2 and V3 (vegetative stages with two and three visible collars) with an average frame rate of 47 frames per second (FPS). This pipeline can also be mounted easily on manned cart, tractor, or field robotic systems for online corn counting.

Feeding ecology of Symbolophorus californiensis larvae (Teleostei: Myctophidae) in the southern transition region of the western North Pacific

2009 ◽  
Vol 90 (6) ◽  
pp. 1249-1256 ◽  
Author(s):  
Chiyuki Sassa
Keyword(s):  
Transition Region ◽  
North Pacific ◽  
Western North Pacific ◽  
Developmental Stages ◽  
Feeding Habits ◽  
Larval Growth ◽  
Trophic Niche ◽  
Size Class ◽  
Gut Contents ◽  
Wide Range

The feeding habits of myctophid larvae of Symbolophorus californiensis were examined in the southern transition region of the western North Pacific where the main spawning and nursery grounds of S. californiensis are formed. This species is a key component of the pelagic ecosystems of this region, and their larvae attain one of the largest sizes among myctophids. To analyse gut contents larvae, including most life history stages after yolk-sac absorption (3.7 to 22.2 mm body length (BL)), were collected in the upper 100 m layer in 1997 and 1998. Feeding incidence was higher during the day than at night (53.1–92.3% versus 0–5.6%), and daytime feeding incidence increased gradually with larval growth. Larvae fed mainly on copepods of various developmental stages. Larvae of S. californiensis showed an ontogenetic change in their diet: larvae ≤7.9 mm BL (i.e. preflexion stage) fed mainly on copepod eggs and nauplii, while the larvae ≥8 mm BL consumed mainly calanoid copepodites such as Pseudocalanus and Paracalanus spp. In the largest size-class (16–22.2 mm BL), the furcilia stage of euphausiids was also an important prey item. There was an increase in the average prey size with growth in larvae ≤11.9 mm BL, while the number of prey eaten positively correlated with growth in larvae ≥12 mm BL. The trophic niche breadth also increased with larval growth, which would ensure a wide range of available food resources for the larger size-class larvae.

Chemical manipulation of Leptosphaeria maculans (blackleg disease) pseudothecial development and timing of ascospore discharge from canola (Brassica napus) residues

2003 ◽  
Vol 54 (9) ◽  
pp. 837 ◽  
Author(s):  
A. D. Wherrett ◽  
K. Sivasithamparam ◽  
M. J. Barbetti
Keyword(s):  
Developmental Stages ◽  
Severe Disease ◽  
Leptosphaeria Maculans ◽  
Potential Method ◽  
Chemical Treatments ◽  
Ascospore Discharge ◽  
Significant Difference ◽  
Significant Efficacy ◽  
Early Seedling ◽  
Disease Pressure

A study was carried out to establish key developmental stages of Leptosphaeria maculans on canola residues leading up to ascospore discharge and how these stages could be affected by chemicals. The residues were dipped in a range of chemicals, including fungicides, herbicides, and surfactants, to determine possible manipulative effects of the chemicals on the development of the fungus including ascospore discharge. Treated residues were placed in the field during the growing season. Ascospore discharge was found to be closely related to pseudothecial maturity and density. There was no significant difference between pseudothecial maturation on the crown component compared with the stem component. A high correlation between rainfall and pseudothecial density suggested that rainfall was a good complimentary indicator for timing of ascospore discharge. These results may provide the canola industry with a potential method of monitoring pseudothecial development for estimating disease hazards. This would allow manipulation of sowing times so as to minimise or avoid heavy ascospore showers coinciding with the early seedling phase. Twenty chemical treatments showed significant efficacy in decreasing ascospore numbers early in the season, most often by delaying the development of the pseudothecia on the residues. Two scenarios were formulated giving growers the potential to manipulate pseudothecial development and/or ascospore discharge. Firstly, a number of chemicals, such as fluquinconazole, technical grade flutriafol, and gluphosinate-ammonium, were able to delay pseudothecial development and subsequent ascospore discharge was decreased by 100%, 99%, and 96%, respectively. This scenario gives growers the potential to minimise synchronisation of ascospore discharge with early crop establishment. Secondly, a situation where pseudothecial development is not delayed, but number of ascospores discharged is reduced (e.g. ziram by 45%) would only be effective if the reduction resulted in a less severe disease epidemic. There is significant potential for development of commercial chemical treatments of residues to reduce disease pressure on seedlings.

The morphology of the British Prostriata with particular reference to Ixodes hexagonus Leach. II

Parasitology ◽  
1953 ◽  
Vol 42 (3-4) ◽  
pp. 161-186 ◽  
Author(s):  
D. R. Arthur
Keyword(s):  
Developmental Stages ◽  
Egg Laying ◽  
The Body ◽  
Dorsal Margin ◽  
Leg Length ◽  
Large Size ◽  
Attachment Sites ◽  
Wide Range ◽  
Primitive Condition ◽  
Basis Capituli

The palps of all stages of Ixodes trianguliceps are provided with a ventral plate below the basal article; formerly this plate was thought to be the first palpal article. This article in the larva and nymph is produced forward into a spur, but in the female tick this spur is incorporated into the basis capituli as the sella. The hypostomes of I. trianguliceps and I. canisuga are redescribed to clear up existing inaccuracies.Ticks in which the rostrum does not extend beyond the apex of the first palpal article are found on birds, and this probably represents a primitive condition. Those with palpal spurs, which may or may not be fused with the basis capituli, are found on birds (not in Britain) or on mammals of the mouse size group, and those where the rostrum is produced beyond the first palpal article occur on a wide range of large and small animals. The longer and more heavily toothed digits of ticks appear to be associated with a wide host range and vice versa. The structure of the digit may also influence the choice of attachment sites by ticks on their hosts because the microstructure of the skin varies in different parts.Variations in size and form of the scuta of some British ticks are described, and the mean growth rate is ascertained from this data. The information shows that the material of I. ricinus and I. hexagonus is homogeneous, and that specific differences occur in size, shape, the position and type of dermal ducts and in the relation between scutal and alloscutal bristles.The morphology of Gené's organ in I. hexagonus is described. It consists of a basal sac-like portion surmounted by four horns and lined with a cuticle beneath an epithelium. The gland is a proliferation of the epithelium and located near the bifurcation of the base into the horns. A watery refractile fluid, secreted by the gland, accumulates between the epidermis and the cuticle in the horn-like extensions. Proximally the thick endocuticle and epidermis lie close together, and two cuticularized rods penetrate the endocuticle for about half-way along the stalk. The rods arise from the postero-dorsal margin of the basis capituli. Muscles, arising from the free ends of the rods, pass back to near the hind-margin of the scutum; they retract the basis capituli after egg laying and indirectly assist in the retraction of Gené's organ. A suggested mechanism for everting Gené's organ in I. hexagonus is outlined.During feeding the opisthosomatic cuticle of all developmental stages of the tick is much stretched. In the larva, where the cuticle is thin, this is effected by the flattening of the epicuticular pleats, but nymphs and females have, in addition, two longitudinal folds alongside the body which stretch to a far greater extent than do the epicuticular pleats. Similar folds are present between the hard ventral plates and the scutum and between the epimeral and median plates in the male. Coupled with the large size of the male digit, this suggests that morphologically, at least, males can imbibe blood.The growth of the leg segments of I. hexagonus is not constant from stage to stage, and as a result the shortest ‘leg-length’ of the female exceeds the longest ‘leg-length’ of the male.

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