File
Title Transcription
ヒカリ キョウド ト コウゴウセイ ソクド ジョウサン ソクド ナラビニ スイリヨウ コウリツ トノ カンケイ カラ ミタ C3 C4 サクモツ ノ トクセイ ノ チガイ
Title Alternative
Response Differences of Photosynthesis, Transpiration and Water Use Efficiency to Light Intensity in C₃ and C₄ Crop Species
Authors
Abstract
To make clear the response differences of photosynthesis,transpiration and water use efficiency to light intensity in C₃ and C₄ crops belonging to Gramineae,the CO₂ exchange and transpiration rates were measured with the attached leaves. Also,water use efficiency, leaf conductance and intercellular CO₂ concentration were calculated based on these measured data. The response of photosynhetic and transpiration rates to light intensity were simultaneously measured using the open system assimilation chamber method provided with a by-pass to dehydrate the water transpired by the leaves. In each crop,light intensity was changed in 9 steps from 110 klx to total darkness. During the measuring,temperature and relative humidity in the chamber were maintained at 30±O.5℃ and 64.3±1.24%,respectively. The results obtained were as follows : 1) Light saturation point,maximum photosynthetic rate and initial slope in the photosynthetic light response curve of C₄ crops were higher compared with those of C₃ crops. 2) The response of the transpiration and water use efficiency to light intensity in both crops saturated at 30 Klx and 10 klx,respectively. The transpiration of C₄ crops was three fourths that of C₃ crops. On the other hand,the water use efficiency of C₄ crops was about twice that of C₃ crops. 3) Leaf conductance and intercellular CO₂ concentration of C₃ crops were larger than those of C₄ crops. 4) There were,in the case of the present experiment,high positive correlations between transpiration and photosynthetic rates in each of the crops. 5) The relations of water use efficiency and intercellular CO₂ concentration with leaf conductance in all crops under high light intensity showed a high negative correlation for water use efficiency and a high positive correlation for intercellular CO₂ concentrations. 6) The higher water use efficiency of C₄ crops was mainly caused by restricting the loss of water vapour from leaves with the smaller Ieaf conductance than those of C₃ crops. 7) Under such small Ieaf conductance,it is considered that the C₄ crops maintain their high photosynthetic rate by means of the high carboxylation efficiency and of the large CO₂ gradient (from the atmosphere to the inside leaves).
Publisher
鳥取大学農学部砂丘利用研究施設.
Content Type
Departmental Bulletin Paper
Link
ISSN・ISBN
0285-2845
NCID
AN00174665
Journal Title
鳥取大学農学部砂丘研究所報告
Current Journal Title
鳥取大学農学部砂丘研究所報告
Volume
22
Start Page
55
End Page
66
Published Date
1983-03
Text Version
Publisher
Rights
(pdfファイル作成は農林水産省農林水産技術会議事務局筑波事務所)
Citation
鳥取大学農学部砂丘研究所報告. 1983, 22, 55-66
Department
Faculty of Agriculture/Graduate School of Agriculture
Language
Japanese