Morphological Characteristics Of Roots Research Articles

Study of morphology and orchid mycorrhizal associations in Malaxis rheedei

The mycorrhizal association in orchids is a striking example of mutualism, where the orchid and the associated mycorrhizal fungi exchange essential nutrients and support each other’s growth and reproduction. The present study focused on a selected terrestrial orchid which is noteworthy for its medicinal value. We aimed to investigate the specific mycorrhizal associations to understand how these interactions influence the morphology of their roots. The morphological characteristics of roots were studied using light microscopy. Transmission electron microscopy studies were conducted to analyze and measure fungal hyphae and peloton sizes as well as to know about fungal colonization distribution. Phylogenetic analysis was conducted to identify the mycorrhizal fungi. Colonization was seen in the 91% root cortex proving high mycorrhizal association. Hyphae appeared in the form of peloton patches at the cortex, occupying up to 62% of the cortical space. The root length with an intact peloton was noted 30% more than the degraded peloton. A single fungus, Tulasnella calospora was isolated from the roots. It was identified using phylogenetic analysis of ITS sequences. Identification of this orchid-mycorrhizal association has the potential to address ecological challenges, contribute to its conservation, and unlock the phytochemical potential of plant-fungus interactions for drug development.

Effects of altitude and varieties on overwintering adaptability and cold resistance mechanism of alfalfa roots in the Qinghai-Tibet Plateau.

The roots are the main functional organs involved in the overwintering adaptability of alfalfa (Medicago sativa). However, it is still unclear how the roots are involved in the cold resistance in the high-altitude area of the Qinghai-Tibet Plateau (QTP). In this study, three winter-surviving 2-year-old alfalfa varieties (M.sativa Zhongmeng No.1, M.sativa Chiza No.1, and M.sativa Gongnong No.1) planted at two different altitudes (2812 m and 3109 m) in the northeast edge of the QTP were used to explore the cold-resistance mechanism. At low altitudes (2812 m), the overwintering rate, taproot length, root area, root surface area, and root average diameter, plant height, fresh yield and hay yield of M.sativa Zhongmeng No.1 were significantly higher (P < 0.01) than for the other two varieties. At high altitude (3109 m), lateral root length, number of lateral roots, main root dry weight, and lateral root dry weight of M.sativa Chiza No.1 were higher (P < 0.01) than the other two varieties. At low and high altitudes, the activities of peroxidase and catalase were higher (P < 0.05) in M.sativa Chiza No.1 during post-winter and pre-winter respectively. At low altitude, higher soluble sugar (P < 0.05) and proline (P < 0.01) contents were recorded during the pre- and post-winter periods. Membership function analysis showed that M.sativa Zhongmeng No.1 has the strongest cold resistance. The structural equation model showed that the overwintering rate of alfalfa was mainly affected by the morphological characteristics of roots and the physiological characteristics of roots, with contribution rates of 0.54 and 0.75 respectively, and the physiological characteristics of roots had the greatest effect on the overwintering rate. This study is of great significance to effectively solve the overwintering of alfalfa, the lack of high-quality legume forage resources, and promote the development of animal husbandry in the alpine areas of the QTP. © 2022 Society of Chemical Industry.

The Effect of Growth Promoting Bacteria on Barley Yield and Morphological Root Characteristics Under Different Water Conditions

The Effect of Growth Promoting Bacteria on Barley Yield and Morphological Root Characteristics Under Different Water Conditions

Karakteristik Morfologi Tanaman Buah di Desa Suka Damai Kecamatan Tungkal Jaya Kabupaten Musi Banyuasin

Research on the Morphological characteristics of fruit plants in Suka Damai Village, Tungkal Jaya District, Musi Banyuasin Regency, has been carried out from April 2021 to June 2021, aims to examine the types of horticultural plants through the morphological characteristics of roots, stems, leaves, flowers and fruit. This study uses a descriptive survey method by exploring the village area as many as 3 RT. Observations were made by looking directly at fruit horticultural plants and then recorded, photographed and then described the morphology. The results obtained 17 species are fruit plants. The species obtained had roots (Radix) with a fibrous root system (Radix adventicia) and a tap (Radix primaria). Stem morphology (Caulis) includes stem types, namely wet stems, grasses and woody. Leaf morphology (Folium) consists of single leaf (Folium simplex) and compound leaf (Folium compositum) with leaf structures including leaf shape (Circumscription) elongated (Oblangus), ovoid (Ovatus), lanceolate (Lanceolatus), sword (Ensiformis), triangle (Triangularis), heart (Cordatus), delta (Deltoideus), ribbon (Ligulatus), jorong (Ovalis). Flower morphology The flower morphology (Flos) is of single flower type (Planta unifloris), and compound flowers (Anthotaxis), which are found in the leaf axils (Flos axillaris) and leaf tips (Flos terminalis). The morphology of fruit (Fructus) was in the types of pseudo fruit (single pseudo, double pseudo, compound pseudo) and true fruit (buni fruit, stone fruit, box fruit, pod). Keywords: horticultural crops, plant morphology

Do chitosan and its derivatives have the same protective effect on drought-contrasting maize genotypes? An analysis of physiological and production processes

Water stress is among the most severe abiotic stress factors for maize production. The application of chitosan causes various responses in plants, as a function of its structure and concentration. Therefore, chemical modifications were proposed in this study to enhance the biological effects on plants. Hybrid maize plants with drought-contrasting characteristics, were subjected to water deficit and spraying with chitosan (CHI) and semi-synthesized chitosan derivatives, N‑Succinyl (SUC) and N,O‑Dicarboxymethyl (MCA). The obtained data show that the application of CHI and its derivatives (0.5 mg.plant-1) led to an increase in production for the two evaluated hybrids in comparison with the control under stress. Regarding leaf gas exchange, over the stress period, it was observed that the application of the MCA derivative yielded greater Pn than the other treatments in plants subjected to drought, in both hybrids. In the evaluation of chlorophyll content, there was an increase in this content through the application of CHI and its derivatives for both maize hybrids under study. With water recovery in plants, the water potential (Ψmd) of those treated with chitosan derivatives was greater than that of the irrigated control plants. In the quantification of proline concentration, higher values were observed in plants treated with MCA derivatives for the drought-sensitive hybrid. Chitosan derivatives, SUC and MCA, were responsible for higher starch concentrations in both maize hybrids. Evaluating the morphological characteristics of roots, the drought-tolerant hybrid showed higher means for all parameters evaluated when subjected to drought, and MCA was responsible for longer root length and greater mean root diameter. The results support the potential use of chitosan and its derivatives to increase tolerance to water deficit in maize

Effect of Waterlogging on Growth and Morphological Characteristics of Roots of Maize Inbred Lines

Effect of Waterlogging on Growth and Morphological Characteristics of Roots of Maize Inbred Lines

Https://hmu.edu.krd/edjjournal/index.php/journal/article/view/79

Background and Objectives: The aim of this study is assessment of the canal morphology of mandibular anterior teeth, the gender differences and between right and left side of them in adult Iraqi Kurdish people using cone-beam computed tomography (CBCT). Subjects and methods: CBCT). Subjects and methods: A retro and prospective study of canal configuration of mandibular anterior teeth by CBCT of a total of 194 subjects 72 males (37.1%) and 122 females (62.9%). Mandible anterior teeth including six teeth for each of 388 central incisor, lateral incisor and canine were analyzed in the database. For classification of morphology of the root canal, Vertucci method was used. Results: There was a non-significant difference between genders. Percentage of more than one canal was 33.1% in central incisors, 33.1% in lateral incisors, and 9.2% in canines. The most common root canal morphology type in all mandibular anterior teeth was type I. Type III was the second most common type in mandibular incisors. Type V was the second most common type in mandibular canines. Conclusion: Canal configuration is subjected to racial and ethnic variations and studying it is important for dental practitioner to understand the variations in root canal morphology of anterior teeth in order to overcome problems when performing endodontic treatment. More studies are needed to further define morphological characteristics of roots of mandibular anterior teeth in Kurdish population.

Boron and calcium deficiency disturbing the growth of trifoliate rootstock seedlings (Poncirus trifoliate L.) by changing root architecture and cell wall

Boron (B) and calcium (Ca) are essential elements for plant growth. Both deficiencies inhibit root growth. However, the mechanism of inhibition is not well clear. Morphological characteristics of roots and changes in root cell wall grown at different B and Ca deficiencies were examined by using a hydroponic culture system. Both B and Ca deficiencies caused reduced plant biomass and root growth. Ca deficiency significantly decreased the fresh weight of root, stem, and leaves by 47%, 50%, and 62%, respectively, while B deficiency only reduced root fresh weight. The PCA combined with Pearson correlation analysis showed that there was significant different correlation among root parameters under B and Ca deficiency treatments when compared to control. The results of observation of transmission electron microscope showed that Ca deficiency reduced but B deprivation increased the thickness of the cell wall. Combining these technologies like X-ray diffraction, fourier transform infrared spectroscopy, homogalacturonan epitopes (JIM5 and JIM7), we confirmed that those changes above may be due to different changes in the degree of methyl esterification of pectin and glycoprotein of the cell wall. Taken together, we concluded that B deficiency can promote the formation of more low methyl esterified pectin to increase cell wall thickness, and then affect the morphological development of root system, while the formation of more highly methyl esterified pectin to increase cell wall degradation under Ca deficiency, which inhibited root elongation and formation of root branches.

地质封存CO2泄漏对玉米根系形态的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 地质封存CO2泄漏对玉米根系形态的影响 DOI: 10.5846/stxb201805311201 作者: 作者单位: 中国农业科学院农业环境与可持续发展研究所,中国科学院地理科学与资源研究所,中国农业科学院农业环境与可持续发展研究所,中国农业科学院农业环境与可持续发展研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31600351）；国家重点研发计划（2016YFC0500508） Impacts of stored CO2 leakage on root morphology of Maize Author: Affiliation: Insititute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agriculture Sciences,Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences,Insititute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agriculture Sciences,Insititute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agriculture Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:碳捕集与封存（Carbon Capture and Storage，CCS）是应对全球气候变化、实现煤炭清洁利用的有效手段之一，但是地质封存的CO2存在泄漏的风险，可能对农田生态系统产生重大威胁，影响我国粮食安全。根系生长是地上部和地下部相互作用、相互促进的统一过程，其形态特征对作物生产力有显著影响，但CCS泄漏对植物根系的影响评估尚不多见。本文以玉米为研究对象，采用盆栽底部通入CO2的方法模拟不同CO2泄漏情景，研究CK（0 g m-2 d-1）和G1000（1000 g m-2 d-1）和G2000（2000 g m-2 d-1）三种泄漏情景下CO2对玉米根系形态的影响。结果表明：CO2泄漏对玉米根系形态有明显的影响，随着泄漏量的增大总根长从40290.81 cm减少至21448.18 cm，减少46.77%，其中细根大幅减少；CO2泄漏造成玉米明显减产，最大减产率达26.64%；玉米的地上部生物量较地下部生物量对CO2泄漏更加敏感。综合来看，随着CO2泄漏量增大，对玉米根的生长、地上部生物量、地下部生物量以及产量有显著的抑制作用。作物根系形态对封存CO2泄漏的响应可为CCS泄漏监测和生态修复提供系统科学依据。 Abstract:Carbon capture and storage (CCS) is an effective technology to address climate change and achieve clean utilization of coal. However, high risk of CO2 leakage from geo-structure still exists, which may pose a threat to farmland ecosystem and food security in China. Root growth is a unified process of interaction and mutual promotion between the upper and underground parts, and the morphological characteristics of root in soil has a great impact on crop productivity. However, the assessment on the effects of CCS leakage on plant roots is rarely reported. In this paper, maize was selected to reveal the response of crop to CO2 leakage by pot experiment. Three treatments, CK (0 g m-2 d-1), G1000 (1000 g m-2 d-1), and G2000 (2000 g m-2 d-1) were designed to simulate different scenarios of CO2 leakage by controlling flux of CO2 at the bottom of pot. The results showed:CO2 leakage had a significant effect on the root morphology of maize. The total root length decreased from 40290.81 cm to 21448.18 cm with increase of CO2 leakage, reduced by 46.77%, of which the fine root decreased greatly. The yield of maize decreased significantly under CO2 leakage treatments, the maximum yield reduction was 26.64%. The aboveground biomass was more sensitive than underground biomass under CO2 leakage. With the increase of CO2 leakage, there was a significant inhibition effect on the root development, aboveground biomass, underground biomass, and yield of maize. The responses of crop root morphology to CO2 leakage provide scientific basis for CCS leakage monitoring and ecological restoration. 参考文献 相似文献 引证文献

Abiotic soil attributes and their relation to morphological root characteristics and mycorrhizal colonization of grasses

This study evaluated soil properties and their relation to root production and arbuscular mycorrhizal fungi (AMF) colonization of grasses. Soil samples were collected from surface layers to determine the volume, total length, specific length, diameter and dry mass of roots, and grain size and chemical properties of the soil. Sampled roots were used to evaluate mycorrhizal colonization and 50 g of soil to extract spores. A second sampling was conducted to measure soil penetration resistance, macroporosity, microporosity, total porosity and bulk density. Of the morphological traits of the roots, only specific length and diameter were significantly related to soil physical attributes. Root volume was positively related with P, Ca, Mg and organic matter. Almost all of the mycorrhizal variables had no correlation with the physical properties of the soil; only total colonization was positively related to soil penetration resistance (to 0.10 m). AMF had a negative correlation between root colonization and total length of the roots, while the number of spores was inversely related to roots finer than 0.5 mm in diameter and positively related to roots larger than 0.5 mm in diameter. The data were highly variable, indicating the influence of environmental heterogeneity on the investigated characteristics.

Cone-Beam Computed Tomography Study of the Root Canal Morphology of Mandibular Anterior Teeth in Serbian Population

Abstract The aim of this study is to describe the morphological characteristics, the number of roots and number of root canals of mandibular central incisors, lateral incisors and canines, and the relationship of these characteristics with the sex and the jaw side where the tooth is located, in the Serbian population using cone-beam computed tomography (CBCT). CBCT images of a total of 902 mandible front teeth, including 296 central incisors, 294 lateral incisors and 312 canines were analyzed in the database. For assessing the morphology of the root canal, Vertucci method of classification was used. Central incisors had two canals in 27%, similar as lateral incisor which had two canals in 26.5%. Mandibular canines had two canals in 7.1% and there was a significant difference between genders. The most prevalent root canal configuration type in all mandibular anterior teeth was type I. In the groups of mandibular incisors with two root canals the most common was type III. In the group of mandibular canines with two root canals, type V had the greatest occurrence. Most mandibular anterior teeth had one root canal. Two root canals were found in 27% of the mandibular incisors. There is a significant difference in root morphology between genders. It is important for dental practitioner to expect different morphological variations when performing endodontic treatment. More studies are needed to further define morphological characteristics of roots of mandibular anterior teeth in Serbian population.

Vegetative Behaviors of the Linden (Tilia spp.) Seedlings

The main goal of this study was to investigate the morphological development of the seedlings of Tilia spp. The experiments were carried out with seeds from three Tilia species. The seeds were harvested from trees in the region of Plovdiv on 30, 45, 60, 75 and 90 days after flowering. The seeds were sown in soil bed immediately after collecting. The sprouting percentage and percentage of developed and survived seedlings were recorded. In a 3-4 leaves development stage, the morphological characteristics of root, stem and leaves were determined. The seedlings have only developed from 90 days seeds. The differences between species were observed. The highest stem was measured in Tilia tomentosa Moench. The largest root system was developed in the seedlings of Tilia platyphyllos Scop. The seed propagation of linden is most effective by using 90 day old seeds.

Gübrelemenin Kayacık (Ostrya carpinifolia Scop.) Fidanlarının Morfolojik Gelişimine Etkisi

In this study, in order to help the mass production of seedlings, the effect of fertilization on the morphological development of hornbeam leafy European hophornbeam (Ostry carpinifolia Scop) seedlings were investigated. For this, seedlings, which were obtained from the seeds coming from different European hophornbeam populations (Düzce-Yığılca, Antalya-Finike, Antalya-Akseki, Kastamonu-Şehdağ ve Adana-Saimbeyli) from various parts of Turkey, were used. European hophornbeam seedlings were treated with different fertilizers, including urea, ammonium sulphate, compound fertilizer 15-15-15 and 20-20-0, and 6-9 months Osmocote release fertilizer, and effects of these fertilizers on the morphological characters were investigated. Fertilization contained the same amount of nitrogen, and was made in three different ways; (1) mixing with habitat, (2) topical application and (3) liquid application. The development of germinated European hophornbeam seeds, which were spring-sowed in the same medium were monitored during the vegetation period. At the end of vegetation period, seedlings were removed from the soil and morphological characteristics of root (seedling length, root collar diameter, root length, fresh root and stem weight of the seedlings, dried root and stem weight of the seedlings and bud number) were measured. As a result, it was observed that fertilization positively affects the development of seedlings and depending on the fertilization type the seedlings of European hophornbeam populations were found to exhibit different improvements/growing. In addition, 6-9 months Osmocote release fertilizers were determined to be the best fertilizers affecting the morphological (diameter and height) development of European hophornbeam populations effectively, and among the populations, Düzce and Kastamonu populations showed the best improvement/growing.

Root morphology and phosphorus uptake by potato cultivars grown under deficient and sufficient phosphorus supply

Information regarding the characteristics that affect P-uptake capacity may assist in the selection of more adapted potato (Solanum tuberosum L.) cultivars and more adequate fertilization management for each cultivar. This study evaluated the P-uptake capacity of potato cultivars (Agata, Asterix, Atlantic, Markies, and Mondial) grown under P-deficient (2mgL−1) or P-sufficient (31mgL−1) conditions in nutrient solution and related it to physiological parameters of uptake and morphological root characteristics. When the plants were 24 days old, they were subjected to a P-uptake kinetics study. The length and surface area of roots and the uptake kinetic parameters (Imax, Km, and Cmin) varied among potato cultivars. Phosphorus-deficient potato plants had an approximately 60% smaller root surface area and an increase of 86% in the Imax and net P influx compared with the plants in P-sufficient conditions. However, these modifications in P uptake kinetics can do not influence P acquisition in the soil environment due to very limited P diffusion. The amount of P accumulated by plants grown under P-deficient conditions was directly related to the root length and surface area; a greater root surface, as demonstrated by the Asterix cultivar, is the most important factor for achieving a greater P-uptake capacity. Under P-sufficient conditions, potato cultivars such as Markies and Mondial showed a balance between morphological root characteristics (medium/large length and surface area) and physiological parameters (medium/high Imax values and net P influx) and had a greater P-uptake capacity. However, under field conditions, the responses to P deficiency may be different due to the very limited diffusion of P in the soil and because plants can use additional mechanisms to improve their P uptake from the soil.

Responses of Root Growth and Nitrogen Transfer Metabolism to Uniconazole, a Growth Retardant, during the Seedling Stage of Soybean under Relay Strip Intercropping System

Relay strip intercropping of soybean has been widely developed in the southwest of China to secure China's soybean production. However, due to the shading from maize, soybean plants are thin and have a poor root system. Uniconazole is a plant-growth retardant that could enhance root vigor; increase root length, root volume, and root dry weight; and affect nitrogen (N) metabolism. To understand the effects of uniconazole on the root growth and N-transfer metabolism of soybean seedlings under relay strip intercropping, the changes in some morphological characteristics of root, dry-matter weight, root vigor, nitrate (NO3 −)-N, ammonium (NH4 +)-N, and amino acid of xylem sap after seed treatment with uniconazole powder (0, 2, 4, and 8 mg kg−1 seed) were investigated. Main root length, total lateral root lengths, first lateral root numbers, root nodule numbers, root vigor together with bleeding sap, bleeding sap–top ratio, root dry weight, and root/shoot ratio were increased, indicating uniconazole improved soybean root system in relay strip intercropping. Uniconazole powder treatment could increase NO3 −-N, NH4 +-N, and total amino acid of xylem sap, to increase the potential of leaf and root N reduction and assimilation, and increase of leaf and root N contents. Thus, results suggested that uniconazole treatment can improve root growth and N transfer mechanism of soybean to support its further growth.

Comparison of root growth and morphological responses to Cadmium and Nickel in two maize cultivars

Two maize cultivars ‘Premjia 190 MB’ and ‘Blitz 160 MB’, in their seedling stage were exposed for 3 days to Cd2+ and Ni2+, separately and also jointly, in concentrations that caused significant inhibition but not cessation of root growth. Primary root growth, cell viability, tissue organization and root system morphology of both cultivars were similar under control conditions. Length of primary roots of both cultivars was significantly reduced by Cd and Ni ions and by the joint treatment (Cd+Ni), under which also early reduction of cell viability occurred. Comparing the two metals, Cd and Cd+Ni proved to be more toxic than Ni alone, with the exception of the effects on ‘Blitz 160 MB’ lateral root formation. Comparing the cultivars, ‘Premija190 MB’ seemed to be more sensitive to Cd and Cd+Ni than to Ni in all studied parameters, while the early reduction of cell viability, activity of lateral root formation and root thickness in ‘Blitz 160 MB’ were more sensitive to Cd+Ni and Ni. The studied growth and morphological characteristics of roots suggest that, at least in the stage of 5 to 6-day-old seedlings, the cultivar ‘Blitz 160 MB’ responded more sensitively to experimentally induced heavy metal stress conditions than did the cultivar ‘Premjia 190 MB’.

Antioxidant enzyme and morphological characteristics of roots of three Nicotiana Tabacum L. genotype seedlings under chilling stress

In order to study the morphological and physiological ecological response of root of Flue-cured tobacco seedling after low temperature stress, this experiment was conducted with different stressful period which was 2, 4 and 6 days under 5 to 7°C (day) by the material named Yunyan87, Msk326 and Yunyan85, respectively. The results showed that comparing with favorable temperature (23 to 25°Cday), activities of superoxide dismutase (SOD) and peroxidase (POD) and ascorbate peroxidase (CAT) had different change trends with difference variety, in which three parameters increased for YY87, and except activities of SOD rise for YY85, other parameters decreased after low temperature stress for short-term (2 days) as for K326 and YY85. When low-temperature stress period prolonged, these parameters come to rise gradually. As for morphological parameters, average diagram, surface area and volume of root declined significant after low-temperature stress for 2 days for YY87, while these morphological parameters are similar to normal level if prolonging stress to 6 days. However all morphological parameters are opposite for K326 comparing with YY87. Surface area, volume of root declined to some extent for YY85. These conclusion indicate different morphological and physiological ecological response mechanisms for roots of Flue-cured tobacco seedling of different variety after chilling stress. Key words: Chilling stress, flue-cured tobacco, morphology, physiology, roots.

Investigation on mechanisms of adaptation of Ammodendron persicum to desert sand dune habitat in arid region

Sand dune habitats in desert regions have harsh conditions for plant establishment and survival. Ammodendron persicum, an psamophyte shrub plant belongs to Leguminosae family, which grows over the desert sand dunes of Zirkohgaen, Gezik and Khash along east part of Iran. Recognizing the adaptive features of the plant species may help towards its conservation and introducing to other sand dune habitats. Therefore, the morphological characteristics of root and shoot, root distribution and forms of regeneration of the species were studied. Observations revealed that each individual plant has a deep taproot along with lateral roots which penetrate in different layers of sand, therefore benefit moisture from top to deeper layers of sand. It has white-grey stems, silver colored and spiny leaf, divided into leaflets. Plant regenerates both through vegetative and reproductive systems. Different mechanisms of adaptation enable the species to adapt in harsh conditions.

Characterization of Cassava Starch Attributes of Different Genotypes

AbstractThe genetic variation of starch of Indonesian cassava genotypes with various morphological characteristics of roots and eco‐geographical origin was characterized and compared. The morphological characteristics of the roots of 71 collected cassava genotypes were classified into yellow and white for flesh colors, purple, pink, light brown, yellow, cream and white for cortex colors, dark brown and light brown for external colors, as well as conical and cylindrical for root shapes. Starch samples extracted from 17 genotypes showed that the amylose content varied from 17.1 to 21.3%. The mean particle size was around 7.3 to 9.7 µm, and the gelatinization onset temperature was in the range of 63.5‐66.1°C. Seven genotypes were analyzed in more detail for their physicochemical properties. The granule size distribution was in the range of 3.2 µm to 17.6 µm for d10 and d90 (i.e. 90% of the granules were bigger than 3.2 μm and 90% were smaller than 17.6 μm), respectively, and the median granule size was around 7.7‐10.8 µm. The gelatinization temperatures of the different cassava starches were in the range of 63.5‐66.1°C. The phosphate content varied from 23.5‐25.3 nmol/mg starch. Particle size distribution and gelatinization temperature as well as the phosphate content of the starch of the selected seven genotypes also showed minor differences among the genotypes. The swelling power of all starches showed some differences between genotypes, but the profiles were similar. The opacity of starch of all the tested genotypes increased twofold within six days, but no large differences among the different genotypes could be detected except for the genotype Ketan. Strength of the gels, which are indicated with force, adhesiveness, cohesiveness, and elasticity, also did not show large differences.

Exudation of organic anions by roots of cabbage, carrot, and potato as influenced by environmental factors and plant age

AbstractA previous study demonstrated that cabbage was P efficient compared to carrot and potato. However, calculating plant P uptake by a mechanistic simulation model based on P transport by diffusion and mass flow, P uptake of roots according to the Michaelis‐Menten kinetics, and morphological root characteristics including root hairs, revealed that these parameters could explain only 2/5 of the total P uptake of cabbage, but 4/5 of that of carrot and potato (Dechassa et al., 2003). Therefore, it was hypothesized that a higher root exudation of organic anions may enhance P mobilization and hence P uptake of cabbage. The objective of this research was to determine root exudation of organic anions by the three species, and to investigate the influence of plant age and dark/light period on organic‐anion exudation by cabbage. Experiments were conducted in a growth chamber in nutrient solution with or without P. Organic anions were determined in root exudates and in root tissue. With cabbage and potato, P deficiency induced exudation of citrate and succinate, respectively. Citrate‐exudation rate of P‐deficient cabbage plants was correlated with accumulation of citrate in root tissue. In contrast, high succinate‐exudation rates in potato were not correlated with an increased concentration in root tissue. For carrot, no change was observed in the exudation of any of the organic anions in response to P deficiency. The results also showed that succinate‐ and citrate‐exudation rates of cabbage roots increased with increased plant age. There was also a significant increase in exudation rates of organic anions of cabbage roots during the light period of the day. It was concluded that cabbage had the ability to exude large amounts of citrate in response to P deficiency by which it can additionally enhance its P‐uptake efficiency, whereas carrot and potato showed little evidence of possessing such a mechanism.