Effect of low root-zone temperature on nodule initiation in narrow-leafed lupin (Lupinus angustifolius L.)

2002 ◽  
Vol 53 (3) ◽  
pp. 355 ◽  
Author(s):  
Sally C. Peltzer ◽  
Lynette K. Abbott ◽  
Craig A. Atkins
Keyword(s):  
Low Temperature ◽  
Root Zone ◽  
Lupinus Angustifolius ◽  
Nodule Development ◽  
Culture Solution ◽  
Mineral N ◽  
Root Zone Temperature ◽  
Low Root Zone Temperature ◽  
Nodule Initiation ◽  
Zone Temperature

The effect of low root-zone temperature on nodulation of Lupinus angustifolius [L.] cv. Yandee was studied using glasshouse experiments in which the effects of temperature on nodule initiation and subsequent nodule development could be assessed separately. Low temperature (7 and 12˚C compared with 25˚C) reduced the growth of both uninoculated plants supplied with adequate mineral N and inoculated plants reliant on fixation alone for their N. However, even at 25˚C, growth of inoculated plants compared with plants supplied with mineral N was limited, and at lower temperatures nodulation was severely inhibited. The most sensitive stage to low root-zone temperature was nodule initiation and there appeared to be a critical temperature between 7 and 12˚C at which initiation did not take place. Increasing the number of bacteria in inocula (from 5 × 103 to 5 × 107 viable cells/mL) did not overcome inhibition. A number of diverse cultivars of L. angustifolius showed the same response as cv. Yandee. Low temperature inhibition of nodule initiation could be overcome by addition of culture solution collected from around the roots of symbioses established at 25˚C. The culture solutions were only effective if the roots at 25˚C were inoculated or, if collected from around uninoculated roots of plants grown with mineral N, they were first exposed to a Bradyrhizobium suspension and then sterilised before addition to cultures at low temperature. The data indicate that both plant and bradyrhizobial factors are required for nodule initiation and that exudation of plant factors at low root-zone temperature is insufficient to stimulate production of the nodulation factors from Bradyrhizobium. At 25˚C, the nodulation zone of lupin roots bore many fractures in the epidermis and showed a high frequency of free root cap border cells, as well as a distinct matrix of extracellular material. These features were significantly reduced at 12˚C and essentially absent at 7˚C, indicating that at low temperature bacterial entry may be restricted.

Physiology and metabolism of grafted bell pepper in response to low root-zone temperature

2019 ◽  
Vol 46 (4) ◽  
pp. 339 ◽  
Author(s):  
Moses Kwame Aidoo ◽  
Tal Sherman ◽  
Naftali Lazarovitch ◽  
Aaron Fait ◽  
Shimon Rachmilevitch
Keyword(s):  
Gas Exchange ◽  
Low Temperature ◽  
Root Zone ◽  
Dry Mass ◽  
Bell Pepper ◽  
Gas Chromatography Mass Spectrometry ◽  
Limiting Factor ◽  
Root Zone Temperature ◽  
Low Root Zone Temperature ◽  
Zone Temperature

Low temperature is a prominent limiting factor for tropical originated crops production in temperate regions, particularly during cool-season production. The diverse response of two rootstocks (Canon-sensitive and S103-tolerant to low root-zone temperature) was studied when exposed to aeroponically different temperature regimes at the root zone: constant low temperature of 14°C low root-zone temperature (LRZT), transient exposure to LRZT of 27–14−27°C and control temperature of 27°C. Gas exchange, shoot dry mass, and root morphology were measured. Shifts in central and secondary metabolite levels in the leaves and roots were examined by gas chromatography-mass spectrometry (GC-MS). Low root-zone temperature inhibited photosynthesis and transpiration of both grafted bell pepper plants; however, self-grafted Canon physiology was impeded to a greater extent compared with Canon grafted onto rootstock S103. Rootstock S103 demonstrated higher sink potential contributing to milder reduction of photosynthesis and transpiration during stress compared with self-grafted Canon. This reduction of gas exchange led to a significant reduction of root maximum length and root dry mass in self-grafted Canon in response to the stress at 14°C compared with Canon grafted onto rootstock S103. In response to stress, GC-MS metabolite profiling showed enhance metabolism in both cultivars’ leaves, as well as in the roots irrespective of the developmental stage of the plant. This evidence combined indicates enhance gas exchange and carbon assimilation when bell pepper is grafted on S103 under low root-zone temperature.

Effects of addition of flavonoid signals and environmental factors on nodulation and nodule development in the pea (Pisum sativum) - Rhizobium leguminosarum bv. viciae symbiosis

Soil Research ◽  
2003 ◽  
Vol 41 (2) ◽  
pp. 267 ◽  
Author(s):  
Mario de A. Lira Junior ◽  
Carlos Costa ◽  
Donald L. Smith
Keyword(s):  
Pisum Sativum ◽  
Rhizobium Leguminosarum ◽  
Nitrogen Availability ◽  
Root Zone ◽  
Nodule Development ◽  
Controlled Environment ◽  
Signal Molecule ◽  
Root Zone Temperature ◽  
Low Root Zone Temperature ◽  
Zone Temperature

The legume–Rhizobium symbiosis is the most important source of biologically fixed nitrogen in agricultural systems. However, it is complex and sensitive to environmental effects, including available mineral nitrogen, soil salinity, and low root-zone temperature. How these factors inhibit the symbiosis is not well understood. If the effects are mostly on the early stages of nodulation, addition of signal molecule(s) may overcome it. Pisum sativum seeds were germinated and the seedlings were inoculated with bacterial culture and cultivated under controlled environment conditions, studying each of the above nodulation-inhibitory factors, under 3 levels: control (little or no inhibitory condition), and moderately or severely inhibitory conditions. Aspects of nodule development (size and number) were measured with a scanner-based technology. All of the environmental conditions studied had effects on both nodule establishment and development. The addition of either hesperitin or naringenin frequently modified nodule development, most markedly under saline conditions. Flavonoid additions had only small effects under high nitrogen availability conditions, and stronger effects under saline and low root zone temperature conditions.

scholarly journals Numerical and Experimental Analyses on Root Zone Temperature in Aeroponic Cultivation Box

2020 ◽  
Vol 38 (4) ◽  
pp. 871-879
Author(s):  
Yahui Luo ◽  
Xiwen Yang ◽  
Pin Jiang
Keyword(s):  
Low Temperature ◽  
Energy Efficient ◽  
Cfd Simulation ◽  
Root Zone ◽  
Single Point ◽  
Maximum Error ◽  
Root Zone Temperature ◽  
Different Temperatures ◽  
Nutrient Solutions ◽  
Zone Temperature

Vegetable growth requires a relatively stable environment for the root zone. If the temperature in root zone environment is optimal, the aeroponic cultivation will be energy-efficient, and the aeroponic vegetables will grow well at high, normal, or low temperature. By computational fluid dynamics (CFD), this paper numerically simulates the root zone temperature of lettuce in the aeroponic cultivation box, after the box was sprayed with nutrient solutions of different temperatures. Then, the root zone environments of aeroponic lettuce were monitored through experiments at three different temperatures: high temperature, normal temperature, and low temperature. Through comparison, it was learned that the error between the simulated and measured values at each point was smaller than 1.35℃; the maximum error at a single point was within 7.4%; overall, the mean relative error was merely 5.8%. The results prove that the proposed CFD simulation model is reasonable and effective. Our research provides a theoretical reference for optimizing the root zone temperature, regulating the spray of nutrient solutions at different temperatures, and building an energy-efficient efficient aeroponic cultivation system.

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