Potassium translocation combined with specific root uptake is responsible for the high potassium efficiency in vegetable soybean

2019 ◽  
Vol 70 (6) ◽  
pp. 516 ◽  
Author(s):  
Changkai Liu ◽  
Bingjie Tu ◽  
Xue Wang ◽  
Jian Jin ◽  
Yansheng Li ◽  
...  

Uptake of potassium (K) in crops depends mainly on the root system. Field, pot and hydroponic experiments were carried out to characterise root morphological traits and examine their roles in K uptake and utilisation of vegetable soybean (edamame) (Glycine max (L.) Merr.). Of 40 genotypes, two high K-efficiency (HKE) and two low K-efficiency (LKE) genotypes were identified and compared at two levels of K application: nil or 120 kg K2SO4 ha–1. HKE genotypes had shorter total root length and smaller root surface area and root volume than LKE genotypes, but responded earlier to low-K conditions by adjusting root architecture. In plants receiving nil K, total root length was increased by 10.4–21.8% for HKE genotypes but decreased by 5.5–9.5% for LKE genotypes at the V4 stage relative to plants receiving applied K. HKE genotypes were more efficient in redistributing K from source to sink tissue, especially from leaf. Of the total K in vegetative tissues, 35.0–46.4% was redistributed to seed in HKE genotypes, whereas only 19.7–28.2% was redistributed in LKE genotypes. HKE genotypes also had a higher specific K uptake rate (K uptake per unit root length), 1.6–1.7 times higher than LKE genotypes at the R5 stage. This indirectly indicated a stronger root K acquisition in HKE genotypes. This study suggests that future vegetable soybean improvement with greater K efficiency should be focused on the selection of higher K-redistribution rate and specific K-uptake rate.

2019 ◽  
Vol 41 (4) ◽  
pp. 313
Author(s):  
Wei Xiaoting ◽  
Zhong Mengying ◽  
Liu Yuehua ◽  
Wu Ruixin ◽  
Shao Xinqing

Root traits are closely related to nutrient absorption and resource competition and can even influence plant recovery and community succession. Grazing can influence root traits directly through trampling and foraging, or indirectly by changing soil characteristics. In the present study, a grazing experiment that involved combinations of grazing season (from June to September) and intensity (rest, moderate and heavy) was conducted in steppe rangeland, Inner Mongolia, China to investigate how the root traits of Leymus chinensis respond to different grazing regimes in the case of aboveground miniaturisation after long-term overgrazing. Root traits such as root length, root surface area, specific root length, root tissue density, root links (unbranched parts of a root connecting either a tip and a branching point or two branching points) and root topological structure were scanned and analysed using Win-RHIZO image analysis software. The results showed that the size of L. chinensis plants was reduced in response to overgrazing, typically by a smaller plant height, total root length, root surface area, root volume, number of tips and number of links. However, root diameter and link length, branching angle and topological structure (herringbone or dichotomous) were unaffected by grazing. Most root traits showed strong correlations under moderate grazing intensity, but not under heavy grazing, indicating that grazing changed the relationships among root traits. Relationships between plant height and root traits (total root length and number of links) shifted from positive to negative as grazing intensity increased, and the trade-off between aboveground and belowground traits was an important adaptive strategy of L. chinensis under heavy grazing. Decreasing grazing intensity in the late grazing season could benefit plant recovery, and a rest in the early grazing season would mitigate root and shoot damage.


HortScience ◽  
2020 ◽  
Vol 55 (8) ◽  
pp. 1272-1279
Author(s):  
Dennis N. Katuuramu ◽  
W. Patrick Wechter ◽  
Marcellus L. Washington ◽  
Matthew Horry ◽  
Matthew A. Cutulle ◽  
...  

Root traits are an important component for productive plant performance. Roots offer immediate absorptive surfaces for water and nutrient acquisition and are thus critical to crop growth and response to biotic and abiotic stresses. In addition, roots can provide the first line of defense against soilborne pathogens. Watermelon crop performance is often challenged by inclement weather and environmental factors. A resilient root system can support the watermelon crop’s performance across a diverse range of production conditions. In this study, 335 four-day-old watermelon (Citrullus spp.) seedlings were evaluated for total root length, average root diameter, total root surface area, and total root volume. Total root length varied from 8.78 to 181 cm (20.6-fold variation), total surface area varied from 2 to 35.5 cm2, and average root diameter and total root volume had an 8- and 29.5-fold variation, respectively. Genotypes PI 195927 (Citrullus colocynthis) and PI 674448 (Citrullus amarus) had the largest total root length values. Accessions PI 674448 and PI 494817 (C. amarus) had the largest total root surface area means. Watermelon cultivars (Citrullus lanatus) had a relatively smaller root system and significantly fewer fibrous roots when compared with the roots of the other Citrullus spp. Positive genetic correlations were identified among total root length, total root surface area, and total root volume. This genetic information will be useful in future breeding efforts to select for multiple root architecture traits in watermelon. Germplasm identified in this study that exhibit superior root traits can be used as parental choices to improve watermelon for root traits.


Author(s):  
Hongliang Tang ◽  
Yazhou Wang ◽  
Le Niu ◽  
Wei Jing ◽  
Yinglong Chen

Alterations in root morphology and physiology are important strategies in plants to adapt to low-phosphorus (P) environments. Maize genotypes differed in nitrogen (N) efficiency may also respond differently to low P stress. This study aimed to investigate the responses of root morphological and physiological traits of these two maize cultivars to P deficit and how these traits were linked with the acquisition of soil P. Two maize cultivars, XY335 (N efficient) and ZD958 (N inefficient), were cultivated for 40 days in a calcareous loamy soil amended with (high P) or without (low P) P. Functional root traits were used to evaluate the morphological and physiological responses to low P supply. Two separate short-term experiments determined the correlation between P uptake rate and P supply intensity (hydroponic) or root hair length under two P treatments (rhizobox). Low P status significantly simulated biomass allocation to roots, specific root length and exudations of carboxylates, while decreased root diameter and rhizosphere pH in both maize cultivars. Two cultivars had different total root length and root surface area under low P stress: increased in ZD958 and decreased in XY335. Both genotypes developed longer root hair under P deficit. ZD958 (greater biomass and shoot P content) has a greater capability at accessing soil P than XY335. Rhizosphere exudation of citric acid was significantly higher in ZD958 than in XY335, while there was not significant genotypic difference in rhizosphere pH and exudation of malic acid and acid phosphatase activity. ZD958 had higher P uptake rate than XY335 when solution P was between 12.5 and 250 µM. This study identified ZD958 as a P-efficient genotype, which better adapted to low P stress by altering root physiological traits (exudation of citric acid and P uptake rate), rather than root morphological traits (total root length, root surface area, root hair length). Our results highlight the importance of analyzing root morphological and physiological traits to enhance our understanding of the physiological mechanisms of P acquisition.


2018 ◽  
Vol 28 (5) ◽  
pp. 629-636 ◽  
Author(s):  
Matthew B. Bertucci ◽  
David H. Suchoff ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Christopher C. Gunter ◽  
...  

Grafting of watermelon (Citrullus lanatus) is an established production practice that provides resistance to soilborne diseases or tolerance to abiotic stresses. Watermelon may be grafted on several cucurbit species (interspecific grafting); however, little research exists to describe root systems of these diverse rootstocks. A greenhouse study was conducted to compare root system morphology of nine commercially available cucurbit rootstocks, representing four species: pumpkin (Cucurbita maxima), squash (Cucurbita pepo), bottle gourd (Lagenaria siceraria), and an interspecific hybrid squash (C. maxima × C. moschata). Rootstocks were grafted with a triploid watermelon scion (‘Exclamation’), and root systems were compared with nongrafted (NG) and self-grafted (SG) ‘Exclamation’. Plants were harvested destructively at 1, 2, and 3 weeks after transplant (WAT), and data were collected on scion dry weight, total root length (TRL), average root diameter, root surface area, root:shoot dry-weight ratio, root diameter class proportions, and specific root length. For all response variables, the main effect of rootstock and rootstock species was significant (P < 0.05). The main effect of harvest was significant (P < 0.05) for all response variables, with the exception of TRL proportion in diameter class 2. ‘Ferro’ rootstock produced the largest TRL and root surface area, with observed values 122% and 120% greater than the smallest root system (‘Exclamation’ SG), respectively. Among rootstock species, pumpkin produced the largest TRL and root surface area, with observed values 100% and 82% greater than those of watermelon, respectively. These results demonstrate that substantial differences exist during the initial 3 WAT in root system morphology of rootstocks and rootstock species available for watermelon grafting and that morphologic differences of root systems can be characterized using image analysis.


Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Yu Liu ◽  
Ji Qian ◽  
Xin Yang ◽  
Bao Di ◽  
Juan Zhou

Abstract Background Traditional measurements of apple seedling roots often rely on manual measurements and existing root scanners on the market. Manual measurement requires a lot of labor and time, and subjective reasons may cause the uncertainty of data; root scanners have limited scanning size and expensive. In case of fruit roots, coverage and occlusion issues will occur, resulting in inaccurate results, but our research solved this problem. Results The background plate was selected according to the color of the seedling roots; the image of the roots of the collected apple seedlings was preprocessed with Vision Development Module by combining image and Labview. The root surface area, average root diameter, root length and root volume of apple seedlings were measured by combining root characteristic parameters algorithm. In order to verify the effectiveness of the proposed method, a set of measurement system for root morphology of apple seedlings was designed, and the measurement result was compared with the Canadian root system WinRHIZO 2016 (Canada). With application of SPSS v22.0 analysis, the significance P > 0.01 indicated that the difference was not significant. The relative error of surface area was less than 0.5%. The relative error of the average diameter and length of the root system was less than 0.1%, and the relative error of the root volume was less than 0.2%. Conclusions It not only proved that the root surface area, average root diameter, root length and root volume of apple seedlings could be accurately measured by the method described herein, which was handy in operation, but also reduced the cost by 80–90% compared with the conventional scanner.


1968 ◽  
Vol 8 (34) ◽  
pp. 533 ◽  
Author(s):  
BWR Torssell ◽  
JE Begg ◽  
CW Rose ◽  
GF Byrne

This paper describes the seasonal growth and morphology of a four-year-old pasture of Townsville lucerne (Stylosanthes humilis) used in a detailed microenvironmental study conducted at Katherine, N.T., during the 1966-67 wet season. Rapid germination and penetration of the tap root followed an early storm rain of 38 mm at the end of September, and most of the seedlings survived the next seven weeks without rain. A second germination followed heavy rain at the end of November, and by the end of December the main development of lateral roots commenced and the rate of shoot development increased. The highest average growth rate, 31 g/m2/day for the period March 31-April 14, was after the last rain of the season and preceded by ten weeks of above average rainfall. Growth continued for a further two weeks while the roots continued to deplete available soil water. During the main period of growth, approximately 80 per cent of root length and 70 per cent of root surface area was in the top 30 cm of soil. The density of root length varied very little below 30 cm. Growth and development are discussed in relation to grass competition and drought adaptation, and fitted to a general description of the life cycle of Townsville lucerne under northern Australian conditions.


Author(s):  
Ömer Sarı

The study was carried out to determine the root architectural characteristics of the one-year saplings of two species of boxwood (Buxus sempervirens L. and Buxus balearica Lam.), which are endangered and natural plants of Turkey, in the greenhouse environment using the WinRhizo root analysis program and scanner. Total root length (cm), root surface area (cm2), root volume (cm3), average root diameter (mm), number of tips, number of forks and number of root crossings were determined in the study. According to the results of the study, the increase in temperature and decrease in humidity values in the second year of both species were effective on the root architectural features. As a result of this effect, the second year root length (3810 cm), number of root tips (2299), number of forks (7007) and number of root crossings (696) increased, root diameter (1.4 mm), root surface area (2158 cm2) and root volume (8 cm3) decreased. As a result, it has been concluded that species can make changes in their root parameters to adapt to different conditions and their adaptability is high. In general, the best results in root architectural parameters were obtained from Buxus balearica on the basis of species.


2021 ◽  
Author(s):  
Changkai Liu ◽  
Xue Wang ◽  
Bingjie Tu ◽  
Yansheng Li ◽  
Heng Chen ◽  
...  

Abstract Aims Vegetable soybean is highly demanded on potassium (K) application. Significant variations of K absorption and utilization exist in vegetable soybean. This study aim at exploring mechanisms of K absorption and utilization of high-efficiency in vegetable soybean by studying the characteristics of root K affinity-associated drivers and photosynthesis in vegetable soybean (edamame) (Glycine max (L.) Merr.).Methods Pot and hydroponic experiments were carried out to examine the characteristics of root K affinity-associated drivers and photosynthesis in vegetable soybean genotypes with different K efficiency. Two K high-efficiency vegetable soybean genotypes and two K low-efficiency genotypes were investigated in low K and normal K conditions. Results The root of K high-efficiency genotypes had a higher K+ affinity associated with higher maximum K+ uptake rate (Imax), but lower Michaelis constant for K+ absorption (Km) and lower compensation concentration for K+ uptake (Cmin). Seedlings of K high-efficiency genotypes also had higher root vigor (TTC reduction method) and greater absorbing activity (methylene blue method), especially in the low K condition. Besides, the root bleeding-sap rate per root length and K upward fluxes rate per root length of K high-efficiency genotypes in beginning seed stage were consistently higher than that of K low-efficiency genotypes. The root of K high-efficiency vegetable soybean genotypes exhibits K+ high-affinity and driving advantages. Photosynthetic parameters of K high-efficiency vegetable soybean genotypes were less affected by low K stress. Low K stress decreased the net photosynthetic rate of K high-efficiency genotypes by 6.1~6.9%, while that of K low-efficiency genotypes decreased by 10.9~15.7%. The higher Chl a/b ratio with enhanced relative content of Chl a in response to low K stress might be an adapted mechanism for K high-efficiency genotypes to maintain photosynthetic capacity.Conclusion Stronger root K affinity drivers associated with photosynthetic adaptability to low potassium stress are the key factors in determining the K high-efficiency of vegetable soybeans.


Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 773 ◽  
Author(s):  
Wang ◽  
Wei ◽  
Li ◽  
Wang ◽  
Ge ◽  
...  

Root system plays an essential role in water and nutrient acquisition in plants. Understanding the genetic basis of root development will be beneficial for breeding new cultivars with efficient root system to enhance resource use efficiency in maize. Here, the natural variation of 13 root and 3 shoot traits was evaluated in 297 maize inbred lines and genome-wide association mapping was conducted to identify SNPs associated with target traits. All measured traits exhibited 2.02- to 21.36-fold variations. A total of 34 quantitative trait loci (QTLs) were detected for 13 traits, and each individual QTL explained 5.7% to 15.9% of the phenotypic variance. Three pleiotropic QTLs involving five root traits were identified; SNP_2_104416607 was associated with lateral root length (LRL), root surface area (RA), root length between 0 and 0.5mm in diameter (RL005), and total root length (TRL); SNP_2_184016997 was associated with RV and RA, and SNP_4_168917747 was associated with LRL, RA and TRL. The expression levels of candidate genes in root QTLs were evaluated by RNA-seq among three long-root lines and three short-root lines. A total of five genes that showed differential expression between the long- and short-root lines were identified as promising candidate genes for the target traits. These QTLs and the potential candidate genes are important source data to understand root development and genetic improvement of root traits in maize.


Author(s):  
Yingying Liu ◽  
Xiaoli Wei ◽  
Zijing Zhou ◽  
Changchang Shao ◽  
Shicheng Su

Chinese windmill palms (Trachycarpus fortunei) are widely planted in karst bedrock outcrop areas in southwest China because of their high economic and ecological values. The aims of this study were to investigate the foraging ability of Chinese windmill palm seedlings planted in six different types of karst microhabitat and to identify the main environmental factors that influence root foraging ability. We planted three-year-old Chinese windmill palm seedlings in six typical karst microhabitats (i.e., rocky trough, rocky surface, rocky gully, rocky soil surface, rocky pit, and soil surface microhabitats). One year after transplanting, the seedlings were excavated to determine the morphological parameters values of new roots and the nutrient concentrations of new roots and leaves. The root foraging ability of Chinese windmill palm seedlings, defined as new root length and new root surface area, was significantly greater in the rocky trough, rocky soil surface, and soil surface microhabitats than in the rocky gully, rocky surface, and rocky pit microhabitats (p < 0.05). Redundancy analysis revealed that the main positive factor affecting the rooting ability of Chinese windmill palm seedlings was soil thickness. Chinese windmill palm seedlings improved their root absorption efficiency by increasing their root length and root surface area under soil nutrient deficiency conditions. The organic carbon, total nitrogen, and available potassium in soil positively influenced the concentration of N and K in roots. Total potassium in soil negatively influenced the biomass of new annual leaves and concentrations of N, P and K in new annual roots and leaves. Chinese windmill palm seedlings can be grown in the different karst microhabitats, especially in the rocky trough, rocky soil surface, and soil surface microhabitats, and, therefore, it is suitable for use in the regeneration of karst forests.


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