高磷胁迫对黄瓜幼苗生长及养分吸收和分配的影响

在不同磷水平(0、0.1、0.5、1.0、10.0、20.0 mmol/L)下培养黄瓜幼苗,研究磷素对黄瓜生长及养分吸收和分配的影响。结果表明,①随磷浓度增加,黄瓜根、茎和叶干重呈先增加后降低的趋势;供磷浓度为10.0 mmol/L时开始产生高磷胁迫症状,症状首先出现在老叶,沿叶脉两侧发黄、有光泽、向上凸起,子叶出现红色坏死斑点,严重时老叶坏死,新叶会出现叶脉间失绿症状。②随供磷水平增加,植株体内磷浓度增加,最高达到干重的1.28%;钾浓度在茎中呈先增加后降低的趋势,铜浓度降低,钙、镁、锰、锌等元素浓度及其在根、茎及叶间分配趋势无显著变化。

木蓝和胡枝子对高磷胁迫的生理生态响应及其磷吸收利用特征

通过模拟土壤不同磷水平,测定木蓝和胡枝子对高磷胁迫的生理生态特性、吸收固定能力的响应。结果表明,木蓝的净光合速率随着磷质量浓度的增大逐渐增大,且各处理间有极显著差异,蒸腾速率也随着磷质量浓度的增大而增大,但各处理间无显著差异;胡枝子的净光合速率和蒸腾速率随着磷质量浓度的增加而逐渐减小,其中净光合速率的变化在各处理间差异极显著,而胞间CO2摩尔分数随着磷质量浓度的增加而显著增加。磷质量浓度的变化对2种植物叶片叶绿素质量分数无显著性影响,但是可引起植物体内可溶性糖质量分数在一定范围内产生变化;木蓝对土壤磷的消减程度和植物体内组织的磷质量分数都高于胡枝子,表明木蓝对土壤的吸收和利用能力高于胡枝子。土壤磷质量分数的增加还会引起植物体内组织磷分配与利用的变化。总体而言,木蓝对高磷土壤的适应与吸收利用能力高于胡枝子,更适宜作为先锋物种对磷矿废弃地进行生态恢复。

核桃实生幼苗光合特性对高磷胁迫的响应

【目的】研究高磷胁迫下核桃砧木苗的光合生理及物质积累特性,为核桃直播建园砧木苗磷肥施用管理提供参考。【方法】以新新2核桃幼苗为材料,比较其在高磷梯度下生物量、光合特性、荧光特性、光合产物及叶片营养元素的影响。【结果】核桃实生幼苗的生物量整体随着施磷量的增加呈下降趋势,净光合速率、气孔导度、胞间CO2浓度、蒸腾速率、初始荧光、最大荧光、最大光化学量子效率及光合色素含量均呈先上升后下降的趋势,在P2处理下达到峰值。核桃幼苗合成的可溶性糖和可溶性蛋白随磷梯度的增大呈上升趋势,酸性磷酸酶活性呈下降趋势。核桃砧木苗叶片中硫、钾、钼、锌、硼和铁元素随着供磷水平的升高呈先扬后抑趋势,于P2处理下达峰值,磷、镁、钙、铜和锰元素随着磷水平的增大而增加,于P4处理下达到最大值,磷过量不利于核桃幼苗对上述元素的吸收。【结论】高磷胁迫显著抑制了核桃幼苗的生长及光合作用,打破了实生核桃幼苗各养分含量之间的平衡。磷水平过高或过低都不利于核桃实生幼苗的生长和发育。

高磷处理下矿山生态型水蓼根系耐受特征

【目的】磷富集植物对高磷具有良好的耐性是其应用于植物修复的前提。本研究探讨磷富集植物矿山生态型水蓼根系对高磷的耐受能力,为后期利用其修复环境中的过量磷提供一定的理论依据。【方法】采用矿山生态型和非矿山生态型水蓼(ME和NME)进行了水培试验,营养液中设置无机磷2、4、8、16 mmol/L 4个高浓度处理,以正常磷0.5 mmol/L浓度为对照,分析对比了两种生态型水蓼根系对高磷的耐受特征。【结果】随着磷浓度的增加,ME地上部和根系生物量和磷积累量均先显著增加后降低,在磷浓度4 mmol/L时出现峰值,而NME则大体呈降低趋势。高磷处理ME地上部和根系生物量分别为NME的1.35~2.56和1.18~1.86倍,除磷浓度16 mmol/L处理外,ME地上部和根系磷积累量分别为NME的1.35~2.58和1.36~1.96倍,磷积累能力更强。ME根系质膜开始受到明显损伤的营养液磷浓度是8 mmol/L,而NME是磷浓度4 mmol/L。随着磷浓度的增加,ME根系中H_(2)O_(2)、MDA和NME根系中的MDA含量均表现为先稳定后显著增加,而NME根系中的H_(2)O_(2)含量则持续增加;两种生态型水蓼根系SOD、POD和CAT活性均先显著增高后降低,分别在磷浓度4和2 mmol/L时显著高于对照。与NME相比,ME根系抗氧化酶活性更高,对H_(2)O_(2)和MDA的清除能力更强。两种生态型水蓼根系亚细胞组分磷含量均表现为可溶部分(含液泡)>细胞壁>细胞器。随着磷浓度的增加,两种生态型水蓼各亚细胞组分磷含量均显著增加,且在磷浓度2和4 mmol/L处理下,根系可溶部分(含液泡)磷分配比例明显高于对照,液泡是其磷素储存的重要场所。【结论】矿山生态型水蓼对高磷的耐受能力和磷积累能力均强于非矿山生态型水蓼。高磷处理下矿山生态型水蓼存在根系自由基和保护酶动态平衡、细胞壁固持和可溶部分的液泡区隔化现象,这是其根系的重要耐受特征。

Differentiation of Barley Genotypes with High Phosphorus Efficiency under Low Phosphorus Stress

[Objective] This study aimed to investigate differences in phosphorus effi-ciency between two-rowed barley and multiple-rowed barley and differences in phos-phorus efficiency among various agronomic traits, and to explore the relationship be-tween agronomic traits and row type with phosphorus efficiency. [Method] Under available phosphorus mass fractions of 1.32 and 36.6 mg/kg, 172 barley varieties, including 79 two-rowed foreign barley, 22 multiple-rowed foreign barley, 58 two-rowed Chinese barley and 13 multiple-rowed Chinese barley, were selected to com-pare differences in phosphorus efficiency-related agronomic traits. Plant height, spike length, number of unfil ed grains, number of unfil ed grains, main panicle weight, to-tal panicle weight, total stem weight, weight of aerial part and heading stage were surveyed for statistical analysis. [Result] The results showed that, various agronomic traits were larger under fertilization condition than under non-fertilization condition ex-cept number of unfil ed grains and heading stage. Plant high, spike length, weight of aerial part and heading stage varied greatly under non-fertilization condition; number of fil ed grains, number of unfil ed grains and total stem weight varied greatly under fertilization condition. In two-rowed barley, plant height and number of fil ed grains of Chinese varieties were higher than those of foreign varieties, while other agronomic traits such as spike length, number of unfil ed grains, main panicle weight, total panicle weight, total stem weight, weight of aerial part and heading stage of foreign varieties were higher than those of Chinese varieties. Spike length and weight of aerial part in multiple-rowed and two-rowed foreign barley were higher than those in Chinese barley. In multiple-rowed barley, plant height, number of unfil ed grains, total panicle weight and total stem weight of foreign varieties were higher under non-fer-tilization condition and lower under fertilization condition compared with those of Chi-nese varieties; number of fil ed grains, main panicle weight and heading stage of foreign varieties were lower under non-fertilization condition and higher under fertil-ization condition compared with those of Chinese varieties. [Conclusion] Heading stage, number of fil ed grains, number of unfil ed grains and total stem weight are more sensitive to phosphorus efficiency. Multiple-rowed barley is more sensitive to phosphorus efficiency than two-rowed barley.