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Responses of Four Species Ephemerals in Brassicacea to Salt Stress and Salt Tolerance Characteristics of Lachnoloma Lehmannii

Author: NuErPaTiMan·MaiMaiTiReYiMu
Tutor: QiMan·YouNuSi
School: Xinjiang Agricultural University
Course: Botany
Keywords: Ephemeral salt stress response Lachnoloma lehmannii salt tolerance characteristics ecological adaptability
CLC: Q945.78
Type: Master's thesis
Year: 2011
Downloads: 60
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Abstract

In this study, use the ephemeral plants of Brassicacea distributed in Northern Xinjiang as material and treated with different concentrations of NaCl solution, indicated that response of ephemerals to salt stress, salt tolerance ability, and ecological adaptability. The experiment includes two parts:1. Four species of ephemeral plant(Lachnoloma lehmannii Bge., Pachypterygium multicaule Kar. et Kir. Bge., Malcormia Africana L. R. Br., and Tetracme quadricornis Steph. Bge.) of Brassicacea as material, treated with different concentrations of NaCl solution, measured to seed germination and plant growth physoilogical index, revealated responses of them to salt stress and their salt tolerance ability were compared, select the plant that has bese salt tolerance ability. The main results are as follows:(1) NaCl stress restrained four speices of ephemeral seed germination different degree, leading to the germination rate, germination index and relative germination rate were decreased with increasing of NaCl concentrations, and relative salt damage rate was increased progressively. Among them salt tolerance ability of Malcormia Africana was lower than others that under 50 mmol·L-1NaCl stress its seed germination rate just was at 4.4%, but Lachnoloma lehmannii observed highest salt tolerance ability that even if 300 mmol·L-1 NaCl stress 22% seeds was germinated.(2) The affect of NaCl lower than 150 mmol·L-1 to plant growth were not significantly, but after then with increasing of salt concentration and elonging of treatment time the plant growth was suffered setback and begin to dye. Unde different concentration of NaCl the four speices ephemerals leaf membrane permeability was increased, relative water content was declined and higher than 200 mmol·L-1 NaCl cause the significant reduction of photosynthetic pigment contents. Among them Lachnoloma lehmannii has the best salt tolerance ability that under 300 mmol·L-1 salinity still alive for 10 d and maintain 75% water content, its leaf membrane permeability was overed 50% at 250 and 300 mmol·L-1 NaCl.2. The aim of second part was measured the uptake of salt ions, photosynthesis characteristics and physiological index, investigate the salt tolerance ability and ecological adaptation michanisim of high salt tolerance spieces Lachnoloma lehmannii.(1) The affecet of different concentration of NaCl to Lachnoloma lehmannii shoot fresh and dry weights higher than underground. With increasing of NaCl concentrations and elongation of treatment time, Lachnoloma lehmannii leaf cellular injury and MDA content were enhanced; relative water content was declined progressly. Under high salinity scavenging of reactive oxygen of Lachnoloma lehmannii was dependent on POD and SOD activity. But the most significant changes of those physiological index observed in after 200 mmol·L-1 NaCl. Under control the photosynthetic pigment content, photosynthesis characteristic parameters such as Pn, Gs, Tr and chlorophyll fluorescence parameters as Fo, ERT, qP of Lachnoloma lehmannii higher than NaCl stressed plants, but decreased significantly at 200 mmol·L-1 NaCl.(2) Under salt condition Lachnoloma lehmannii absorb the Na+, K+ and after 200 mmol·L-1 NaCl neither Na+ or K+ content in leaves increased to a much greater extent than roots, thereby increasing of Na+/K+. Different concentration of NaCl stress enhanced the Lachnoloma lehmannii leaf PM H+-ATPase activity, but higher than 150 mmol·L-1 NaCl stress reduced root PM H+-ATPase activity significantly; root activity of Lachnoloma lehmannii was reached the high level at 100 mmol·L-1 NaCl treatment but under 250 and 300 mmol·L-1 NaCl stress declined significantly, this results similar to uptake of Na+, K+.(3) In the different treatment time of salt stress, with increasing of NaCl concentration, proline and soluble sugar content of Lachnoloma lehmannii leaves were increased significantly but starch content was decreased slightly. At the NaCl stressed for 5 d, the soluble protein content of Lachnoloma lehmannii was increased significantly but tends to decrease when stressed for 10 and 20 d.

Responses of Four Species Ephemerals in Brassicacea to Salt Stress and Salt Tolerance Characteristics of Lachnoloma Lehmannii

Abstract

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