scholarly journals Influence of Nitrogen Enrichment during Reproductive Growth Stage on Leaf Nitrogen Accumulation and Seed Yield in Soybean

2014 ◽  
Vol 17 (3) ◽  
pp. 209-217 ◽  
Author(s):  
Xin Zhao ◽  
Shao-Hui Zheng ◽  
Susumu Arima
Keyword(s):  
Seed Yield ◽  
Growth Stage ◽  
Leaf Nitrogen ◽  
Nitrogen Accumulation ◽  
Nitrogen Enrichment ◽  
Reproductive Growth

Nitrogen accumulation and partitioning in shoots of cotton plants infested with two-spotted spider mites

1997 ◽  
Vol 48 (4) ◽  
pp. 525 ◽  
Author(s):  
V. O. Sadras ◽  
L. J. Wilson
Keyword(s):  
Nitrogen Concentration ◽  
Reproductive Organs ◽  
Spider Mites ◽  
Leaf Nitrogen ◽  
Rapid Decline ◽  
Nitrogen Accumulation ◽  
Reproductive Growth ◽  
Large Reservoir ◽  
Main Site ◽  
Allometric Analysis

In cotton (Gossypium hirsutum L.), leaves are the main site of nitrogen reduction and constitute a large reservoir of organic nitrogen. Foliar herbivores, therefore, are likely to have detrimental effects on the nitrogen economy of the plant. A field experiment was conducted to investigate the effects of two-spotted spider mites (Tetranychus urticae Koch) on the accumulation and partitioning of nitrogen in cotton shoots. Control plants and plants infested with mites 3 times in the growing season were compared. Once established, mite colonies grew exponentially. After peaking at 35–64 mites/leaf, mite numbers declined sharply. Mites markedly affected both shoot nitrogen accumulation and partitioning. The amount of nitrogen in shoots of mite-infested plants peaked earlier than in controls, and reached maximum values that were 50–69% of the controls. Early infestation (at the onset of reproductive growth) had a greater effect than infestations initiated during active reproductive growth. The concentration of nitrogen in leaves declined faster in mite-infested plants than in controls, mostly due to accelerated leaf senescence. This rapid decline in leaf nitrogen concentration could be one of the factors involved in the collapse of mite colonies in heavily infested plants. Nitrogen concentration of stems and reproductive organs was generally greater in mite-infested plants than in controls. Allometric analysis showed that this was related to both the small size of mite-infested plants, and true increases in nitrogen content probably associated with translocation from senescing leaves.

scholarly journals Estimation of Paddy Rice Nitrogen Content and Accumulation Both at Leaf and Plant Levels from UAV Hyperspectral Imagery

2021 ◽  
Vol 13 (15) ◽  
pp. 2956
Author(s):  
Li Wang ◽  
Shuisen Chen ◽  
Dan Li ◽  
Chongyang Wang ◽  
Hao Jiang ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Regression Models ◽  
Growth Stage ◽  
Vegetation Index ◽  
Leaf Nitrogen ◽  
Paddy Rice ◽  
Growth Stages ◽  
Nitrogen Accumulation ◽  
Plant Nitrogen ◽  
Stage Models

Remote sensing-based mapping of crop nitrogen (N) status is beneficial for precision N management over large geographic regions. Both leaf/canopy level nitrogen content and accumulation are valuable for crop nutrient diagnosis. However, previous studies mainly focused on leaf nitrogen content (LNC) estimation. The effects of growth stages on the modeling accuracy have not been widely discussed. This study aimed to estimate different paddy rice N traits—LNC, plant nitrogen content (PNC), leaf nitrogen accumulation (LNA) and plant nitrogen accumulation (PNA)—from unmanned aerial vehicle (UAV)-based hyperspectral images. Additionally, the effects of the growth stage were evaluated. Univariate regression models on vegetation indices (VIs), the traditional multivariate calibration method, partial least squares regression (PLSR) and modern machine learning (ML) methods, including artificial neural network (ANN), random forest (RF), and support vector machine (SVM), were evaluated both over the whole growing season and in each single growth stage (including the tillering, jointing, booting and heading growth stages). The results indicate that the correlation between the four nitrogen traits and the other three biochemical traits—leaf chlorophyll content, canopy chlorophyll content and aboveground biomass—are affected by the growth stage. Within a single growth stage, the performance of selected VIs is relatively constant. For the full-growth-stage models, the performance of the VI-based models is more diverse. For the full-growth-stage models, the transformed chlorophyll absorption in the reflectance index/optimized soil-adjusted vegetation index (TCARI/OSAVI) performs best for LNC, PNC and PNA estimation, while the three band vegetation index (TBVITian) performs best for LNA estimation. There are no obvious patterns regarding which method performs the best of the PLSR, ANN, RF and SVM in either the growth-stage-specific or full-growth-stage models. For the growth-stage-specific models, a lower mean relative error (MRE) and higher R2 can be acquired at the tillering and jointing growth stages. The PLSR and ML methods yield obviously better estimation accuracy for the full-growth-stage models than the VI-based models. For the growth-stage-specific models, the performance of VI-based models seems optimal and cannot be obviously surpassed. These results suggest that building linear regression models on VIs for paddy rice nitrogen traits estimation is still a reasonable choice when only a single growth stage is involved. However, when multiple growth stages are involved or missing the phenology information, using PLSR or ML methods is a better option.

scholarly journals NITROGEN ACCUMULATION AND PARTITIONING BY WINGED BEAN IN RESPONSE TO SUPPORT SYSTEMS

1998 ◽  
Vol 34 (1) ◽  
pp. 41-53 ◽  
Author(s):  
M. R. MOTIOR ◽  
W. O. WAN MOHAMAD ◽  
K. C. WONG ◽  
Z. H. SHAMSUDDIN
Keyword(s):  
Total Nitrogen ◽  
Seed Yield ◽  
Support Systems ◽  
Nitrogenase Activity ◽  
Leaf Nitrogen ◽  
Winged Bean ◽  
Nitrogen Partitioning ◽  
Nitrogen Accumulation ◽  
Dry Matter Accumulation ◽  
Local Cultivar

An experiment was carried out to determine the partitioning and accumulation of nitrogen in plant components, nitrogenase activity and their relationships with seed yield of a local cultivar of winged bean (Psophocarpus tetragonolobus (L.) DC.) grown on three support systems of 0, 1, and 2 m height under field conditions. Total nitrogen accumulation and nitrogen partitioning were determined throughout the growing season by measuring nitrogen content and concentration in above-ground plant tissues (leaves, stems, petioles and pods). Support heights of 1 and 2 m significantly increased total nitrogen accumulation in component parts of the plant, nitrogenase activity, nodulation, total dry matter accumulation and seed yield compared with the control. Plants grown on supports accumulated significantly higher leaf nitrogen at the vegetative stages and the contribution of seed nitrogen was also significantly higher compared with unsupported plants. Nitrogenase activity increased with onset of flowering but declined during the pod formation stage in plants grown on a support system. Unsupported plants showed higher nitrogenase activity prior to flowering possibly due to lack of photosynthate and, consequently, early senescence of leaves.

Spatial imaging reveals the pathways of Zn transport and accumulation during reproductive growth stage in almond plants

2021 ◽  
Author(s):  
Ruohan Xie ◽  
Jianqi Zhao ◽  
Lingli Lu ◽  
Judy Jernstedt ◽  
Jiansheng Guo ◽  
...  
Keyword(s):  
Growth Stage ◽  
Reproductive Growth

Fluctuation of 20-hydroxyecdysone in individual organs of Achyranthes japonica during reproductive growth stage and its accumulation into seed

2013 ◽  
Vol 56 (3) ◽  
pp. 335-338 ◽  
Author(s):  
Kyung Hwan Boo ◽  
Doseung Lee ◽  
Quyen Van Nguyen ◽  
Seong Beom Jin ◽  
Seungtae Kang ◽  
...  
Keyword(s):  
Growth Stage ◽  
Reproductive Growth ◽  
Achyranthes Japonica

Monitoring leaf nitrogen in wheat using canopy reflectance spectra

2006 ◽  
Vol 86 (4) ◽  
pp. 1037-1046 ◽  
Author(s):  
Yan Zhu ◽  
Yingxue Li ◽  
Wei Feng ◽  
Yongchao Tian ◽  
Xia Yao ◽  
...  
Keyword(s):  
Nitrogen Concentration ◽  
Leaf Nitrogen ◽  
Reflectance Spectra ◽  
Nutrition Status ◽  
Nitrogen Accumulation ◽  
Canopy Reflectance ◽  
Leaf Nitrogen Concentration ◽  
Non Destructive ◽  
N Status ◽  
Leaf N

Non-destructive monitoring of leaf nitrogen (N) status can assist in growth diagnosis, N management and productivity forecast in field crops. The objectives of this study were to determine the relationships of leaf nitrogen concentration on a leaf dry weight basis (LNC) and leaf nitrogen accumulation per unit soil area (LNA) to ground-based canopy reflectance spectra, and to derive regression equations for monitoring N nutrition status in wheat (Triticum aestivum L.). Four field experiments were conducted with different N application rates and wheat cultivars across four growing seasons, and time-course measurements were taken on canopy spectral reflectance, LNC and leaf dry weights under the various treatments. In these studies, LNC and LNA in wheat increased with increasing N fertilization rates. The canopy reflectance differed significantly under varied N rates, and the pattern of response was consistent across the different cultivars and years. Overall, an integrated regression equation of LNC to normalized difference index (NDI) of 1220 and 710 nm of canopy reflectance spectra described the dynamic pattern of change in LNC in wheat. The ratios of several near infrared (NIR) bands to visible light were linearly related to LNA, with the ratio index (RI) of the average reflectance over 760, 810, 870, 950 and 1100 nm to 660 nm having the best index for quantitative estimation of LNA in wheat. When independent data were fit to the derived equations, the average root mean square error (RMSE) values for the predicted LNC and LNA relative to the observed values were no more than 15.1 and 15.2%, respectively, indicating a good fit. Our relationships of leaf N status to spectral indices of canopy reflectance can be potentially used for non-destructive and real-time monitoring of leaf N status in wheat. Key words: Wheat, leaf nitrogen concentration, leaf nitrogen accumulation, canopy reflectance, spectral index, nitrogen monitoring

scholarly journals Physiological and Agronomic Responses of Four Rice Varieties to Drought in the Rainforest

2018 ◽  
Vol 10 (2) ◽  
pp. 220-227 ◽  
Author(s):  
Mamadou FOFANA ◽  
Lekan Suleiman SAKARIYAWO ◽  
Mauton O. POPOGBE ◽  
Akeem A. OYEKANMI ◽  
Jamiu O. AZEEZ ◽  
...  
Keyword(s):  
Water Deficit ◽  
Growth Stage ◽  
Upland Rice ◽  
Water Status ◽  
Block Design ◽  
Physiological Mechanism ◽  
International Institute ◽  
Reproductive Growth ◽  
Rice Varieties ◽  
And Control

The present investigation tested the hypothesis that there would be variation in physiological responses to water deficit among rice varieties from different production ecologies, with contrasting tolerance to water deficit under repeated cycle of soil moisture deficit, at reproductive growth stage. A screen house and a field trial were conducted at International Institute of Tropical Agriculture, Ibadan and Ikenne (Latitude 6° 52' N, Longitude 3° 43' E) respectively. Both experiments had rice varieties (‘IR 64’, ‘WAB 56-104’, ‘IR 77298-1-2-B-10’ and ‘NERICA 4’) and stress status (stress and control) as treatment factor’s, arranged in a randomised complete block design with three replicates. In both trials, the physiological mechanism that underpins varietal differences with repeated cycles of water deficit at the reproductive growth stage was more balanced water status, improved foliar characters, efficient photosynthetic capacity and higher grain yield in comparatively drought tolerant upland rice varieties (‘NERICA 4’ and ‘WAB 56-104’), as opposed with the results for the drought susceptible cultivar ‘IR 64’. A converse pattern was observed on water stressed rice, despite fewer cycles of water deficit on the field. The results could have suggested that the initiation of water deficit is the rate limiting step rather than its intensity at the reproductive growth stage.    

scholarly journals Silicon improves rice grain yield and photosynthesis specifically when supplied during the reproductive growth stage

2016 ◽  
Vol 206 ◽  
pp. 125-132 ◽  
Author(s):  
Alyne O. Lavinsky ◽  
Kelly C. Detmann ◽  
Josimar V. Reis ◽  
Rodrigo T. Ávila ◽  
Matheus L. Sanglard ◽  
...  
Keyword(s):  
Grain Yield ◽  
Growth Stage ◽  
Rice Grain ◽  
Reproductive Growth

Differential Responses of Soybean Cultivars to Propanil

Weed Science ◽  
1973 ◽  
Vol 21 (4) ◽  
pp. 279-281 ◽  
Author(s):  
R. J. Smith ◽  
C. E. Caviness
Keyword(s):  
Oryza Sativa ◽  
Glycine Max ◽  
Seed Yield ◽  
Growth Stage ◽  
Main Stem ◽  
Leaf Injury ◽  
Soybean Cultivars ◽  
Differential Responses ◽  
Over The Top

Ten commercial soybean [Glycine max (L.) Merr.] cultivars were evaluated for reaction to over-the-top applications of two rates of 3′,4′-dichloropropionanilide (propanil) at the growth stage when three nodes on the main stem had completely unrolled leaves. Propanil, a herbicide commonly applied to rice [Oryza sativa L.] for control of grass weeds, was applied at 0.56 and 3.36 kg/ha; the higher rate is commonly used for control of weeds in rice. ‘Davis’, ‘Hood’, and ‘York’ soybean cultivars were damaged more by propanil than ‘Hill’, ‘Lee’, ‘Lee 68’, ‘Pickett’, ‘Semmes’, ‘Bragg’, or ‘Dare’ when damage was measured by reductions in seed yield and stand and by leaf injury.

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