塔里木河下游植物生理指标及土壤水盐和养分数据集（2000-2006）

在生态系统中，土壤和植被是相互依存的两个因子，植物影响土壤，土壤制约植被。一方面，土壤中贮存着大量的碳、氮、磷等营养物质；另一方面，土壤养分有效性对植物的生长和发育起着关键的作用，并直接影响着植物群落的组成与生理活力，决定着生态系统的结构、功能和生产力水平。
土壤含水率（或土壤含水量）：在塔里木河下游的大西海子至台特玛湖这一区段的9个断面内，依据地下水位监测井的布设，沿垂直于河道的方向设置植物样地。在每个样地挖1个土壤剖面，每个剖面分层自下而上采集0-5、5-15、15-30、30-50、50-80、80-120和120-170cm土层土样各一个，每个土样由相应土层多点采样混合而成，每个土层都用铝盒采土样，现场称湿重，用烘干法测土壤含水率（或土壤含水量）。
土壤养分：混合土样剔除植物根系及石砾等杂物，在室内风干后过筛，用于测定土壤养分。有机质采用重铬酸钾外加热法，全氮用半微量-开氏法，全磷用硫酸-高氯酸-钼锑抗比色法，全钾用氢氟酸-高氯酸-火焰光度计法，有效氮采用碱解扩散法，有效磷采用碳酸氢钠浸提-钼锑抗比色法，有效钾用乙酸铵浸提-火焰光度计法，PH、电导率分别用酸度计和电导率仪测定（水土比为5：1）。
土壤水溶性总盐用原位盐分仪现场测定法。
干旱胁迫是植物逆境最普遍的形式，也是影响植物生长发育的主要因子。植物器官在逆境情况下会发生膜脂过氧化作用，从而积累膜脂过氧化物的最终分解产物丙二醛(MDA)，MDA含量是反映膜脂过氧化作用强弱和质膜受破坏程度的重要标志，也是反映水分胁迫对植物造成伤害的重要参数；同时植物在逆境条件下，体内活性氧代谢加强会导致活性氧或其它过氧化物自由基的积累从而伤害细胞膜。植物体内超氧化物歧化酶(SOD)和过氧化物酶(POD)则能够在干旱等逆境中清除植物体内过量的活性氧，维持活性氧的代谢平衡，保护膜结构，最终增强植物对逆境的抗性。
分析样本以塔里木河下游主要建群种胡杨、柽柳以及芦苇等为研究对象。结合地下水监测井位置，从河边开始设置6个样地，每个样地间隔50 m，依次为1，2，3，4，5和6号样地，采集植物的鲜叶，低温保存，当天做前处理(烘干或冰冻)。室内测试细胞水势调节物脯氨酸(PRO)、细胞膜系统保护酶超氧化物歧化酶(SOD)和过氧化物酶(POD)。
酶液制备：称取新鲜材料0.5g，加4.5mL pH7.8的PBS。材料在预先冰冻的研钵中匀浆，研钵置于冰浴中。10000 r/min离心15 min，上清液用于超氧化物歧化酶，过氧化物酶和丙二醛(MDA)测定。
PRO测定：将0.03 g材料放入20 mL大试管中加入10mL无氨蒸馏水，封口后置沸水浴中30min，冷却后过滤，滤液5 mL+茚三酮5 mL，沸水中显色60min，甲苯萃取。萃取液用日本岛津UV-265型紫外分光光度计在波长515 nm处比色。
SOD活性测定：用氮蓝四唑(NBT)光还原法。酶反应体系加样次序为：pH 7.8 PBS 2.4mL+核黄素0.2 mL+蛋氨酸0.2 mL+EDTA0.1 mL+酶液0.1 mL+NBT0.2 mL。然后将试管在40001ux光下反应20 min，进行光化还原，用UV-265紫外分光光度计在650 nm波长处测量SOD活性。
POD活性测定：反应混合液为50 mLpH6.0PBS+28 μL愈创木酚+19 uL30％H2O2。2 mL反应混合液+1 mL酶液，立即开始计时，每隔1 min读数一次，读数于470 nm处进行。
叶绿素的测定：乙醇丙酮混合液法。将叶片剪碎后，称取0.2 g，丙酮：无水乙醇=1：1的混合液为提取液，在暗处浸提24 h后，叶片变白，叶绿素全部溶解在提取液中，分光光度计在652nm下测定叶绿素OD值。
可溶性糖的测定方法：采用硫酸苯酚法。(1)标准曲线的制作取20 ml刻度试管11支，从0-10分加编号，分别按表1加入溶液和水。然后按顺序向试管内加人1 ml 9％苯酚溶液，摇均，再从管液正面以5～20 S时间加入5 ml浓硫酸，比色液总体积为8 ml，在恒温下放置3O分钟，显色。然后以空白为对照，在485 nm波长下比色测定，以糖为横坐标，光密度为纵坐标，绘制标准曲线，求出标准曲线方程。(2)可溶性糖的提取取新鲜植物叶片，擦净表面污物，剪碎混匀，称取0.1-0.3 g，共3份，分别放入3支刻度试管中，加入5-l0 ml蒸馏水，塑料薄膜封口，于沸水中提取3O分钟，提取液过滤入25 ml容量瓶中，反复冲洗，定容至刻度。(3)吸取0.5 g样品液于试管中，加蒸馏水1.5 ml，同制作标准曲线的步骤，求出可溶性糖的含量。
各试管中溶液和水的量
管号 0 1-2 3-4 5-6 7-8 9-10
1.100μg/L糖液 0 0.2 0.4 0.6 0.8 1.0
2.水/ml 2.0 1.8 1.6 1.4 1.2 1.0
3.可溶性糖量/μg 0 20 40 60 80 100

丙二醛的测定方法：硫代巴比妥酸法。新鲜叶片剪碎，称取0．5 g，加入5％ 的TCA5 ml，研磨后所得匀浆在3 000 r／rain下离心10 rain。取上清液2 ml，加0．67％TBA 2 ml，混合后在100 水浴上煮沸30 rain，冷却后再离心一次。以0．67％TBA溶液为空白，测定450、532、600 nm处的OD值。
植物激素(GA3、ABA、CK、IAA)分析测试方法：取0.1±0.005g植物样品，液氮中研磨。500μl甲醇4℃提取过夜。样品离心，上清液冷冻干燥。30μl10％的CH3CN溶解样品。样品溶液10μl于HPLC分析。植物激素外标法定量。标准植物激素购于sigma公司。分析方法见（阮晓，王强,等，2000年，植物生理学报.26（5），402-406）。

In terrestrial ecosystems, soil and vegetation are two interdependent factors: plants influence soil properties, while soil restricts vegetation development. On one hand, soil stores substantial amounts of nutrients including carbon, nitrogen and phosphorus; on the other hand, soil nutrient availability plays a critical role in plant growth and development, directly affects the composition and physiological vigor of plant communities, and determines the structure, function and productivity of the entire ecosystem.

Soil moisture content (soil water content): In the 9 sampling sections spanning from Daxihaizi to Taitema Lake in the lower reaches of the Tarim River, vegetation sample plots were established perpendicular to the river channel based on the layout of groundwater level monitoring wells. One soil profile was excavated in each plot, and soil samples were collected layer-by-layer from bottom to top at depths of 0-5, 5-15, 15-30, 30-50, 50-80, 80-120 and 120-170 cm. Each soil sample was a composite of multiple subsamples from the corresponding soil layer. Soil samples were collected using aluminum boxes, their fresh weights were measured on-site, and soil moisture content was determined via the drying method.

Soil nutrients: Mixed soil samples were purified by removing plant roots, gravel and other impurities, then air-dried indoors and sieved prior to nutrient analysis. The analytical methods for soil nutrients are as follows: soil organic matter by potassium dichromate external heating method; total nitrogen by semi-micro Kjeldahl method; total phosphorus by sulfuric acid-perchloric acid-molybdenum antimony colorimetric method; total potassium by hydrofluoric acid-perchloric acid-flame photometry method; available nitrogen by alkaline hydrolysis diffusion method; available phosphorus by sodium bicarbonate extraction-molybdenum antimony colorimetric method; available potassium by ammonium acetate extraction-flame photometry method; pH and electrical conductivity were measured using a pH meter and conductivity meter respectively, with a soil-water ratio of 5:1.

Total water-soluble soil salts were determined by on-site measurement using an in-situ salinity meter.

Drought stress is the most prevalent form of plant abiotic stress and a key factor limiting plant growth and development. Under adverse environmental conditions, plant organs undergo membrane lipid peroxidation, resulting in the accumulation of malondialdehyde (MDA), the final decomposition product of membrane lipid peroxides. MDA content serves as an important indicator of the intensity of membrane lipid peroxidation and the degree of plasma membrane damage, as well as a critical parameter reflecting the harm caused by water stress to plants. Additionally, under stress conditions, enhanced intracellular reactive oxygen metabolism leads to the accumulation of reactive oxygen species and other peroxide free radicals, which damage cell membranes. Superoxide dismutase (SOD) and peroxidase (POD) in plants can eliminate excessive reactive oxygen species under stresses such as drought, maintain reactive oxygen metabolism homeostasis, protect cell membrane structures, and ultimately enhance plant resistance to abiotic stresses.

The analysis samples were collected from the main constructive plant species in the lower reaches of the Tarim River, including Populus euphratica, Tamarix ramosissima, Phragmites australis, etc. Based on the locations of groundwater monitoring wells, 6 sample plots were set up starting from the river bank, with a 50 m interval between adjacent plots, numbered 1 to 6 sequentially. Fresh plant leaves were collected, stored at low temperatures, and pre-treated (dried or frozen) on the same day. The following indicators were analyzed in the laboratory: proline (PRO, a cellular osmoregulatory substance), and the membrane-associated protective enzymes superoxide dismutase (SOD) and peroxidase (POD).

Enzyme solution preparation: Weigh 0.5 g of fresh plant material, add 4.5 mL of phosphate buffered saline (PBS) at pH 7.8. Grind the material in a pre-chilled mortar placed in an ice bath. Centrifuge the homogenate at 10,000 r/min for 15 min, and the collected supernatant was used for the determination of SOD, POD and MDA activities.

Proline (PRO) determination: Place 0.03 g of plant material into a 20 mL large test tube, add 10 mL of ammonia-free distilled water, seal the tube, and incubate in a boiling water bath for 30 min. After cooling, filter the extract, transfer 5 mL of the filtrate to a new tube, add 5 mL of ninhydrin reagent, incubate in boiling water for 60 min for color development, and extract the colored product with toluene. The absorbance of the toluene extract was measured at 515 nm using a Shimadzu UV-265 ultraviolet spectrophotometer.

SOD activity determination: The nitroblue tetrazolium (NBT) photochemical reduction method was employed. The enzyme reaction system was prepared by adding reagents in the following order: 2.4 mL of PBS (pH 7.8) + 0.2 mL of riboflavin + 0.2 mL of methionine + 0.1 mL of EDTA + 0.1 mL of enzyme extract + 0.2 mL of NBT solution. The test tube was then exposed to 4000 lux light for 20 min to initiate the photochemical reduction reaction, and SOD activity was measured at 650 nm using a UV-265 ultraviolet spectrophotometer.

POD activity determination: The reaction mixture was formulated as 50 mL of PBS (pH 6.0) + 28 μL of guaiacol + 19 μL of 30% H2O2. Transfer 2 mL of the reaction mixture to a cuvette, add 1 mL of enzyme extract, start timing immediately, and record the absorbance at 470 nm every 1 min.

Chlorophyll determination: Ethanol-acetone mixed extraction method. Cut plant leaves into small pieces, weigh 0.2 g, use a mixed solution of acetone:absolute ethanol = 1:1 as the extraction solvent, and soak in the dark for 24 h until the leaves turn completely white and all chlorophyll is dissolved in the extract. The absorbance of the extract was measured at 652 nm using a spectrophotometer.

Soluble sugar determination: Sulfuric acid-phenol method was used. (1) Standard curve preparation: Take 11 20 mL graduated test tubes, label them from 0 to 10, and add the corresponding volumes of sugar solution and distilled water according to the table below. Then add 1 mL of 9% phenol solution to each tube, mix thoroughly, followed by adding 5 mL of concentrated sulfuric acid within 5-20 s, resulting in a total volume of 8 mL for the colorimetric solution. Incubate at constant temperature for 30 min to develop color. Use the blank (tube 0) as a control, measure the absorbance at 485 nm, and plot a standard curve with soluble sugar content as the x-axis and optical density as the y-axis to derive the standard curve equation. (2) Soluble sugar extraction: Wipe clean the surface of fresh plant leaves, cut and mix evenly, weigh 0.1-0.3 g for three replicates, transfer each to a graduated test tube, add 5-10 mL of distilled water, seal with plastic film, extract in a boiling water bath for 30 min, filter the extract into a 25 mL volumetric flask, rinse the residue repeatedly, and dilute to the volume mark with distilled water. (3) Take 0.5 mL of the sample extract, add 1.5 mL of distilled water, follow the same procedure as standard curve preparation, and calculate the soluble sugar content.

The volumes of reagents and water in each test tube:
| Tube Number | 0 | 1-2 | 3-4 | 5-6 | 7-8 | 9-10 |
|-------------|------|------|------|------|------|------|
| 100 μg/L sugar solution / mL | 0 | 0.2 | 0.4 | 0.6 | 0.8 | 1.0 |
| Distilled water / mL | 2.0 | 1.8 | 1.6 | 1.4 | 1.2 | 1.0 |
| Soluble sugar content / μg | 0 | 20 | 40 | 60 | 80 | 100 |

Malondialdehyde (MDA) determination: Thiobarbituric acid (TBA) method. Cut fresh leaves into small pieces, weigh 0.5 g, add 5 mL of 5% trichloroacetic acid (TCA), grind into a homogenate, and centrifuge at 3000 r/min for 10 min. Transfer 2 mL of the supernatant to a test tube, add 2 mL of 0.67% TBA solution, mix well, boil in a 100 ℃ water bath for 30 min, cool to room temperature, and centrifuge again. Use 0.67% TBA solution as the blank control, and measure the absorbance values at 450, 532 and 600 nm.

Plant hormone (GA3, ABA, CK, IAA) analysis and testing: Weigh 0.1 ± 0.005 g of plant sample, grind into a fine powder in liquid nitrogen. Extract the ground sample with 500 μL of methanol at 4 ℃ overnight. Centrifuge the extract, and freeze-dry the supernatant. Dissolve the dried extract in 30 μL of 10% CH3CN solution. Inject 10 μL of the dissolved sample for high performance liquid chromatography (HPLC) analysis. Plant hormones were quantified using the external standard method. Standard plant hormones were purchased from Sigma Company. The analytical protocol refers to (Ruan, X., Wang, Q., et al., 2000, Acta Phytophysiologica Sinica, 26(5), 402-406).

搜集汇总

背景与挑战

背景概述

该数据集包含2000-2006年塔里木河下游地区植物生理指标（如SOD、POD活性）和土壤水盐养分数据，覆盖9个断面不同土层，采用标准实验室方法测定，为研究干旱区生态系统的土壤-植被关系提供了重要基础数据。