Effects of low phosphorus stress on photosynthetic and chlorophyll fluorescence characteristics of alfalfa with different root types
View Fulltext  View/Add Comment  Download reader
  
DOI:10.7606/j.issn.1000-7601.2024.01.17
Key Words: low phosphorus stress  alfalfa  root type  photosynthesis  chlorophyll fluorescence
Author NameAffiliation
XIA Jing College of Pratacultural Science, Gansu Agricultural University Key Laboratory of Grassland Ecosystem, Ministry of Education, Lanzhou, Gansu 730070, China 
NAN Lili College of Pratacultural Science, Gansu Agricultural University Key Laboratory of Grassland Ecosystem, Ministry of Education, Lanzhou, Gansu 730070, China 
CHEN Jie College of Pratacultural Science, Gansu Agricultural University Key Laboratory of Grassland Ecosystem, Ministry of Education, Lanzhou, Gansu 730070, China 
MA Biao College of Pratacultural Science, Gansu Agricultural University Key Laboratory of Grassland Ecosystem, Ministry of Education, Lanzhou, Gansu 730070, China 
YAO Yuheng College of Pratacultural Science, Gansu Agricultural University Key Laboratory of Grassland Ecosystem, Ministry of Education, Lanzhou, Gansu 730070, China 
HE Haipeng College of Pratacultural Science, Gansu Agricultural University Key Laboratory of Grassland Ecosystem, Ministry of Education, Lanzhou, Gansu 730070, China 
ZHANG Zelong College of Pratacultural Science, Gansu Agricultural University Key Laboratory of Grassland Ecosystem, Ministry of Education, Lanzhou, Gansu 730070, China 
Hits: 10
Download times: 13
Abstract:
      To explore the responses and adaptability of leaf photosynthesis and chlorophyll fluorescence of different root\|type alfalfas under low phosphorus stress in the first year and the following year, a pot experiment using three root types of alfalfa of creeping rooted Medicago varia Martin ‘Gongnong No.4’, tap rooted M. sativa ‘Longdong’, and rhizomatous rooted M. sativa ‘Qingshui’as the experimental materials was conducted. The effects of low phosphorus stress on photosynthesis parameters, carotenoid content, chlorophyll content, and chlorophyll fluorescence parameters were studied. The results showed that the chlorophyll a, chlorophyll b, carotenoids and chloroplast pigment content, photosynthetic and fluorescence parameters of alfalfa of different root types were reduced under low phosphorus stress, compared with the normal the decrease rate was between 2.9%~47.9%, 2.1%~47.8%, 8.1%~57.8%, 2.6%~7.8%, 0.5%~60.2%, and 1.1%~52.0%, respectively, indicating that non\|stomatal factors limited the photosynthesis of alfalfa under phosphorus stress. The photosynthetic performance of alfalfa plants was weakened by the destruction of the photoreaction center of alfalfa plants under low phosphorus stress. The intercellular CO2 concentration, water use efficiency and non\|photochemical quenching coefficient of alfalfa increased by 2.9%~12.2%, 10.0%~96.5% and 5.7%~27.4%, respectively. The chlorophyll a, chlorophyll b, carotenoids, chloroplast pigment contents, net photosynthetic rate, stomatal conductance, and stomatal limitation value of rhizome alfalfa were most affected in the first year and the following year, which decreased by 47.9%, 47.8%, 57.8%, 47.8%, 37.5%, 22.1%, 19.8%, and 16.6%, 24.5%, 16.6%, 19.0%, 35.4%, 54.2%, 24.2%, respectively. From the point of view, tap rooted and creeping rooted alfalfa showed greater resistance to low phosphorus stress than rhizomatous rooted alfalfa.The correlation analysis further showed that the structure and physiological state of PSII system in alfalfa leaves under low phosphorus stress were damaged, and chlorophyll was decomposed in large quantities, which inhibited photosynthetic electron transport and hindered photosynthesis.