scholarly journals Ecophysiological properties of a cluster root-forming plant, Helicia cochinchinensis (Proteaceae) grown on Miyajima Island, Japan

Author(s):  
Jun Wasaki ◽  
Tadashi Okamura ◽  
Taiki Yamauchi ◽  
Hayato Maruyama ◽  
Shinji Uchida ◽  
...  

Abstract Aims The family Proteaceae is one of the dominant families in nutrient-impoverished habitats in the Southern hemisphere, and less common in the Northern hemisphere. Helicia cochinchinensis Lour. is the only Proteaceae species in Japan. This study aimed to unveil the ecophysiological properties of H. cochinchinensis grown on Miyajima Island, Hiroshima, Japan.Methods Phosphorus (P) status and dynamics of soils in H. cochinchinensis habitats were measured. Plant P and nitrogen (N) concentrations of leaves were measured after digestion. Roots and rhizosheath soil were collected to assess root morphology and root exudates.Results Available P (Olsen-P) in soils in habitats of H. cochinchinensis was 0.46–3.7 mg P kg-1 soil. Citrate was the major carboxylate in root exudates and its concentration increased during cluster-root formation. Acid phosphatase activity was greater at the surface of cluster roots that on the surface of other roots and bulk soil, especially for mature cluster roots. Sparingly soluble organic P concentrations decreased in the rhizosheath soil of mature cluster roots. The P concentrations of H. cochinchinensis leaves were relatively low; 0.34–0.69 mg P g-1 DW and 0.15–0.29 mg P g-1 DW in mature and senesced leaves, respectively. The P demand of H. cochinchinensis was less than that of nearby trees, showing greater P-remobilization efficiency.Conclusions Phosphorus mobilization from unavailable P by cluster roots supported P uptake by H. cochinchinensis, and P remobilization from senescing leaves contributed to sustain growth under P-deficient conditions.

1990 ◽  
Vol 68 (12) ◽  
pp. 2564-2570 ◽  
Author(s):  
Suzanne Racette ◽  
Isabelle Louis ◽  
John G. Torrey

The term cluster root is used to refer to a dense cluster of determinate lateral roots (rootlets), in preference to the terms proteoid root and proteoid-like root used by other authors. Cluster roots are often formed by the actinorhizal plant Gymnostoma papuanum. In water culture, cluster root formation by G. papuanum was influenced by aeration, phosphorus level, and nitrogen source. Aeration was a critical factor, with nonaerated rooted cuttings having far fewer cluster roots than aerated ones. Phosphorus deficiency was the single nutrient deficiency that led to increased cluster root formation. Seedlings, grown under conditions of either low (0.8 mg∙L−1) or no phosphorus, responded by devoting a greater portion of root growth to the production of cluster roots, with no overall reduction in root growth for 6 weeks. The response to varying phosphorus level was modified by providing nitrogen in different forms. Supplying nitrogen as ammonium resulted in low levels of cluster root formation. Supplying nitrate to nodulated seedlings led to an increase in cluster root formation in comparison with plants that depended solely upon dinitrogen fixation by Frankia. Greatest cluster root formation occurred on plants grown in aerated water cultures supplied with nitrate and with little or no phosphorus. Key words: Gymnostoma papuanum, cluster roots, proteoid roots, phosphorus deficiency.


1989 ◽  
Vol 67 (6) ◽  
pp. 1708-1712 ◽  
Author(s):  
Ruhama Berliner ◽  
John G. Torrey

Actinomycorrhizal symbiosis was studied in Comptonia peregrina (L.) Coult. and in Myrica gale L., both of the Myricaceae. Root nodules were common in all Comptonia plants in their natural habitats and in pot cultures under greenhouse conditions. Spontaneous actinorhizal infection under greenhouse conditions differed in two native forest soils. Spontaneous mycorrhizal infection in C. peregrina and in M. gale was found neither in natural habitats nor in plants growing in native forest soils under greenhouse conditions. Comptonia peregrina and M. gale inoculated with the actinomycete Frankia, with the vesicular–arbuscular mycorrhizal fungus Glomus intraradices, or with Frankia and G. intraradices together were infected by Frankia only. The nodulated plants were significantly larger compared with unnodulated plants, and their root systems showed acetylene reduction in a bioassay for nitrogenase activity. Uninfected Comptonia plants that grew in a forest soil under greenhouse conditions developed well when watered with a complete mineral nutrient solution or with a solution that lacked phosphorus, but degenerated when watered with a solution that lacked combined nitrogen or with deionized water. Comptonia peregrina and M. gale formed cluster roots that resembled proteoid roots in the Proteaceae. In Comptonia, cluster-root formation in sand culture was common in nodulated plants as well as in unnodulated plants. In M. gale, cluster-root formation was common in nodulated plants and infrequent in unnodulated plants.


2021 ◽  
Vol 11 ◽  
Author(s):  
Yue Liu ◽  
Huichun Yang ◽  
Qi Liu ◽  
Xiaowen Zhao ◽  
Sasa Xie ◽  
...  

Intercropping of soybean and sugarcane is an important strategy to promote sustainable development of the sugarcane industry. In fact, our understanding of the interaction between the rhizosphere and bacterial communities in the intercropping system is still evolving; particularly, the influence of different sugarcane varieties on rhizosphere bacterial communities in the intercropping process with soybean, still needs further research. Here, we evaluated the response of sugarcane varieties ZZ1 and ZZ9 to the root bacterial community during intercropping with soybean. We found that when ZZ9 was intercropped with soybean, the bacterial diversity increased significantly as compared to that when ZZ1 was used. ZZ9 played a major role in changing the bacterial environment of the root system by affecting the diversity of rhizosphere bacteria, forming a rhizosphere environment more conducive to the growth of sugarcane. In addition, our study found that ZZ1 and ZZ9 had differed significantly in their utilization of nutrients. For example, nutrients were affected by different functional genes in processes such as denitrification, P-uptake and transport, inorganic P-solubilization, and organic P-mineralization. These results are significant in terms of providing guidance to the sugarcane industry, particularly for the intercropping of sugarcane and soybean in Guangxi, China.


Horticulturae ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 302
Author(s):  
Miguel A. Quiñones ◽  
Susana Fajardo ◽  
Mercedes Fernández-Pascual ◽  
M. Mercedes Lucas ◽  
José J. Pueyo

Two white lupin (Lupinus albus L.) cultivars were tested for their capacity to accumulate mercury when grown in Hg-contaminated soils. Plants inoculated with a Bradyrhizobium canariense Hg-tolerant strain or non-inoculated were grown in two highly Hg-contaminated soils. All plants were nodulated and presented a large number of cluster roots. They accumulated up to 600 μg Hg g−1 DW in nodules, 1400 μg Hg g−1 DW in roots and 2550 μg Hg g−1 DW in cluster roots. Soil, and not cultivar or inoculation, was accountable for statistically significant differences. No Hg translocation to leaves or seeds took place. Inoculated L. albus cv. G1 plants were grown hydroponically under cluster root-promoting conditions in the presence of Hg. They accumulated about 500 μg Hg g−1 DW in nodules and roots and up to 1300 μg Hg g−1 DW in cluster roots. No translocation to the aerial parts occurred. Bioaccumulation factors were also extremely high, especially in soils and particularly in cluster roots. To our knowledge, Hg accumulation in cluster roots has not been reported to date. Our results suggest that inoculated white lupin might represent a powerful phytoremediation tool through rhizosequestration of Hg in contaminated soils. Potential uptake and immobilization mechanisms are discussed.


2011 ◽  
Vol 156 (3) ◽  
pp. 1025-1032 ◽  
Author(s):  
Lingyun Cheng ◽  
Bruna Bucciarelli ◽  
Jianbo Shen ◽  
Deborah Allan ◽  
Carroll P. Vance

Soil Research ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 397 ◽  
Author(s):  
David Nash ◽  
Murray Hannah ◽  
Kirsten Barlow ◽  
Fiona Robertson ◽  
Nicole Mathers ◽  
...  

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.


Sign in / Sign up

Export Citation Format

Share Document