1996 Fiscal Year Final Research Report Summary
Effects of differences in medium conditions on the water metabolism of plants
Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants |
|Research Institution||IWATE UNIVERSITY |
HARA Michihiro Iwate University, Department of Agronomy and Forestry, Associate Professor, 農学部・農林生産学科, 助教授 (80003763)
INADA Ikuko Iwate University, Department of Agronomy and Forestry, Research Assistant Profes, 農学部・農林生産学科, 助手 (90110650)
SHONO Hiroshi Iwate University, Department of Agronomy and Forestry, Research Assistant Profes, 農学部・農林生産学科, 助手 (90235721)
|Project Period (FY)
1995 – 1996
|Keywords||root medium / water metabolism / evapo-transpiration / water transfer function / water potential / soil moisture sensor / volumetric heat capacity / three dimensional leaf-tip angle distribution|
The following four terms have been measured and analyzed.
(1) Differences in evapo-transpiration and growth of tomato corresponding to different soil moisture regimes
Tomato (Lycopersicum esculentum Mill.) plants were grown for 28 days under five different soil moisture regimes (SMRs), viz non-irrigated, and irrigated up to field capacity (FC) level allowing 60,45,30, and 15% depletion of FC moisture (DFCM). The plants showed a higher weekly average evapo-transpiration (ET) rate, and a higher cumulative ET after 28 days after transplanting (DAT) when more water was made available in their root zone through irrigation. Biomass production in different plant parts and water use efficiency increased significantly with frequent irrigations allowing minimum soil drying from FC level. Nitrogen dilution effects in different plant parts were observed for the wetter SMRs. However, total N uptake was remarkably enhanced with increased availability of soil moisture. Significant and positive correlat
ions of biomass production with water use and N uptake were noted.
(2) Measurement and analysis of the water movement in soil
When a 1 L soil was pressurized from the field capacity to 501cmH_2O,1000cmH_2O and so on, the amount of water come out through a fine ceramic pipe was measured and found to be an exponential function of time. The transfer function of the soil was expressed as a one order delay element which had a static gain k and a time constant T.The maximum depression in the water potential when the total soil moisture of m moves through the soil in d day was proportional to m/k and the proportional coefficient was well approximated with [(2T/d)^2+(1/2)^2]^(1/2)+1/2.
(3) Development of heat dissipation type sensor probes for soil moisture measurement
A temperature sensor was set at the middle of two cylindrical heaters. The maximum temperature rise and the occurring time was measured when the heat was generated from the cylindrical heaters as a square wave form. The volumetric heat capacity, thermal diffusivity and heat conductivity were then obtained at the same time. The change in the soil moisture content was well estimated from the measured volumetric heat capacity change.
(4) Analysis of the three dimensional distribution of leaf tip angles and three dimensional outlines of shape
Three dimensional distribution of leaf tip angles and three dimensional outlines of shape of tomato plants were measured by the method of image measurement based on textural features proposed by Shono (1995), and its availability was verified. An algorithm for simplifying the complicated information for efficient transaction was proposed. From the discussion on the results, the following conclusions were derived. (i) three dimensional distribution of leaf tip angle and three dimensional outline of shape of tomato plants can be measured separately fairly well especially in upper and younger regions. (ii) because crowded leaves in lower and older regions have different tendencies in leaf tip angle between inner layr and outer one, three dimensional measurement is very effective for measuring the proper condition of leaf tip angle. The analysis is helpful in understanding the meaning of the shape information. Less
Research Products (2 results)