【作者】 石勇；

【导师】 陈少良；

【作者基本信息】 北京林业大学 ， 植物学， 2008， 硕士

【摘要】 在干旱盐碱地区进行生态环境建设,除了着眼于筛选抗旱耐盐植物,还要加大造林绿化的技术含量,以提高林木的成活率和保存率,本文就是尝试利用吸水剂来提高我国重要速生树种的抗旱耐盐性。实验选取抗逆性较弱、对逆境条件较敏感的群众杨(P.‘popularis 35-44’)为实验材料,研究吸水剂对苗木的抗盐、抗旱能力的影响,同时分析和比较两种吸水剂A. Stocksorb 500 XL(颗粒状吸水剂,德国Stockhausen化学公司研制生产的新型吸水剂-,主要成分为:钾-聚丙烯酸脂-聚丙烯酰胺共聚体)和B. Luquasorb?(粉末吸水剂,由BASF-巴斯夫公司生产的超强吸水剂,其主要成分为:聚丙烯酸-丙烯酸钠交联体)对提高苗木抗逆性的效果,主要实验结果如下:1.吸水剂可以有效的提高植物的抗旱能力,干旱处理下施加吸水剂之后,相对高生长速度最高增加了2.73倍,这一结果与本实验的前期研究工作结果相似。同时土壤中施加吸水剂后,盐浓度被稀释,降低了土壤的盐碱程度,减弱了土壤对植物的盐胁迫,也提高了植物的抗盐能力。2.吸水剂可以维持苗木在干旱下的正常蒸腾水分蒸腾量,苗木的根系生长在吸水剂之中,即便在干旱胁迫下也可以得到足够的水分来维持正常的生长需要.在盐胁迫下第3天苗木日蒸腾耗水量即出现显著降低,而吸水剂处理后第9天才出现上述现象.干旱胁迫下第6天苗木日蒸腾耗水量显著下降,而吸水剂处理后将这一症状推迟了9天。3.盐和干旱胁迫都会造成苗木的气孔关闭、气体交换量降低、有效光化学量子产量(ΦPSII)下降等,而施加吸水剂后可以在一定时期和一定程度内缓解这些影响.盐胁迫下,随着处理天数增加,气孔导度直线下降,在第30天左右下降到80mmol/m2s1 .而施加吸水剂后,可将气孔导度维持在90-100mmol/m2s1.同时ΦPSII也最高提高了1.15倍;干旱胁迫下,吸水剂处理后,气孔导度和ΦPSII分别提高了1.71倍和1.14倍。4.由于根在生长中向水生长,细根可以整条穿过多个吸水剂颗粒,吸水剂强大的吸水能力为根的生长创造了一个富水和低盐的微环境,在很大程度上减弱了逆境因素对苗木的不利影响。因此在盐和干旱胁迫下,吸水剂处理苗木的根、叶中胁迫离子(Na+、Cl-)累计量降低,由于吸水剂自身富含K+,同时也为苗木提供了营养离子,最终提高了植株的抗旱耐盐性。5.干旱和盐处理会影响苗木的抗氧化系统,导致苗木出现伤害症状,.而施加吸水剂后维持膜抗氧化能力的抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性下降速率降低,同时将苗木胁迫症状最多推迟了51天,同时将苗木的生物量最高提高了1.17倍。6.两种吸水剂虽然都能促进群众杨的抗旱耐盐性,但作用特点有所不同,颗粒状吸水剂吸水倍率略低,吸水速度慢,但是供水速率快,日供水量大;并且由于根在生长中因为向水生长,成熟的根可以整条穿过多个吸水剂颗粒生长。粉末吸水剂的吸水速度快,吸水倍率高,可以迅速的保持住土壤中可以利用的水资源,减少水分的自然流失和蒸发,但是粉末吸水剂的供水速度较慢日供水量小,供水速度慢,使得在同样的吸水倍率下,粉末吸水剂可以更长久的为苗木提供水分,与颗粒吸水剂相比,可以将延缓苗木出现干旱症状的天数增加20天。更多还原

【Abstract】 It needs to improve methodology for afforestation in arid and saline areas in addition to screening salt- and drought-resistant plant material. In this research the intolerant tree species-P.popularis were chosen as an experiment material to investigate the different effects two kinds of hydrogel on drought and salt resistance. Polymers used are: Stocksorb 500 XL (granule type, crosslinked poly potassium-co-(acrylic resin polymer)-co-polyacrylamide hydrogel) that manufactured by Stockhausen GmbH Krefeld (Germany), and hydrogel-Luquasorb? series products,powder type, made from partially neutralised, lightly cross-linked poly(acrylic acid) by BASF company (Germany). The experimental results and the main conclusions are summarized:1. In gerneral, the two types of polymers enhanced the drought resistance of P.popularis, e.g. relative growth rates of height-RGRH was increased by 2.73-fold. Result is consistent to our further studies. Moreover, hydrogel amendment also increased the salt resistance of the P.popularis. The application of polymers decreased the intensity of salinity by diluting the salt ions in the soil solution, thus enhanced salt tolerance of this tree species.2. Water or salt stressed plants retained higher level of whole-plant water loss, indicating hydrogel amendment supplied water to plant roots. Whole-plant water loss was declined after 3 days of salt treatment, but hydrogel-treated plants exhibited deceased evaporation on day 9. Similarly, Whole-plant eveporation decreased after 6 days of drought treatment, but it occurred 9 day later in hydrogel-treated plants.3. Water and salt stress reduced the stomatal conductance (GS), leaf gas exchange and the maximum quantum yield of PS II (ΦPSII), however, hydrogel amendment decreased the drought- and NaCl-induced decline of these parameters. For Example, stomatal conductance rapidly decreased after the onset of salt stress, and reached the minimum, 80 mmol m-2 s-1 on day 30. In comparison, hydrogel-treated plants remaned GS at 90-100 mmol m-2 s-1. At the same time the ΦPSII of polymer-treated plants were 1.15 times higher than non–hydrogel-treated plants. Similarly, GS andΦPSII of polymer-treated plants were 1.71- and 1.14-fold higher than non–hydrogel-treated plants under water stress.4. The roots grewgrow through the granule polymers during the experimental period. The polymer retained large amount of water which could supply a lower salt condition for root growth, thus reducing the intensity of water shortage and salinity. Therefore, the concentration of toxic ions of Na+ and Cl- were greatly diluted. Moreover, and the hydrogels used in this study also are rich of K+, The polymer could supply this nutrient element for plant growth, which increased water and salt tolerance of P. popularis plants.5. Salt and drought stress weakened the defense system of plant, resulting in leaf damage. Hydrogel application reduced the drought- and salt-induced decline of ascorbic peroxidase (APX), and glutathione reductase (GR). As a result, stress-induced leaf damage was delayed by 51 days and biomass of polymer-treated plants was increased by 1.17-fold, as compared to stressed plants without hydrogel amendment.6. There were different effects of polymers on plant resistance although the two types of hydrogels enhanced salt and water tolerance of plants. The granule hydrogel absorbs less water then the powder one, but it supplied water more quickly. The powder hydrogel supplied less water per day, but it could prolong the supplying duration. As a result, the occurrence of drough-induced leaf damage in powder hydrogel-treated plants was 20 days later than the powder hydrogel-treated plants.更多还原