Responses of dinitrogen fixation and photosynthetic activity in mashbean (Vigna aconitifolia) cultivars under low P conditions

• Published in: Soil science and plant nutrition (Tokyo) Vol. 44; no. 1; pp. 31 - 41
• Main Authors: Chaudhary, M.I. (Hiroshima Univ., Fukuyama (Japan). Faculty of Applied Biological Science), Fujita, K
• Format: Journal Article
• Language: English
• Published: Tokyo Taylor & Francis Group 01-02-1998; Japanese Society of Soil Science and Plant Nutrition
• Subjects: Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Biological and medical sciences; biomass production; BNF; Deficiencies. Phytotoxicity of elements. Salinity; FIJACION DEL NITROGENO; FIXATION DE L'AZOTE; FOSFORO; FOTOSINTESIS; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Genetics and breeding of economic plants; mashbean; NITROGEN FIXATION; P absorption; PHOSPHORE; PHOSPHORUS; PHOTOSYNTHESE; PHOTOSYNTHESIS; Soil-plant relationships. Soil fertility. Fertilization. Amendments; VARIEDADES; Varietal selection. Specialized plant breeding, plant breeding aims; VARIETE; VARIETIES; VIGNA ACONITIFOLIA; Asia; Honshu; Japan; Soil fertility; Variety trial; low concentration; Mechanism analysis; Biomass; Inorganic element; Field experiment; Biological productivity; Absorption; Nitrogen fixation; Diazotrophy; Adaptation; Symbiosis; Macronutrient(mineral); Subtropical zone; dinitrogen; Nutrition; Tolerance; Phosphorus; Vigna aconitifolia; Varietal selection; Ecophysiology; Grain legume; Screening; Biological fixation; Vegetable crop; Genetic improvement; Concentration effect; Photosynthesis; Soil plant relation; Cultivar
• ISSN: 0038-0768; 1747-0765
• DOI: 10.1080/00380768.1998.10414424

To examine the factor controlling the low P tolerance in the case of biological nitrogen fixation (BNF) and photosynthetic activity (Po), nine mashbean cultivars (three for each of early, medium, and late maturity groups) were selected for field experiments under two P levels of 10 kg P ha(-1) (low P) and 100 kg P ha(-1) (control ) and dry matter weight, leaf area, leaf number, Po, and acetylene reduction activity (ARA) were determined at the vegetative and flowering stages. At low P, the relative while plant dry weight was reduced to more than 50% which was more significant in early and medium maturity groups than late maturity one. Low P application led to an increase in the dry matter distribution into roots in all the cultivars. Low P conditions decreased both leaf number and average leaf area, and those reductions were more pronounced in early maturity cultivars, which resulted in a greater reduction of photosynthesis on a whole plant basis than BNF at both growth stages. However, Po remained relatively stable at both P levels regardless of the maturity groups. The P content was significantly decreased in leaf blades and stem + petioles of all the cultivars. Nodules and roots showed a relatively higher P content than other plant parts, suggesting that under suboptimal P conditions, underground parts acquire P preferentially. Under the low P application conditions all the cultivars absorbed less than 50% of P amount relative to the respective control plants. Low P application conditions resulted in more than 50% reduction in N accumulation than in the control. It is, therefore, suggested that the early and medium cultivars are more susceptible to low P conditions in terms of biomass production than late maturity ones because of the larger reduction in photosynthesis due to the inhibition of leaf emergence and development than BNF