金琥快速水培技术及其根系适应性的研究

为了探索仙人掌科金琥(Echinocactus grusonii)的快速培育技术,比较了静止水培和常规基质栽培对金琥生长的影响及其根系的适应性。结果表明,金琥在供试的5种营养液配方中静置水培均能正常生长,水培163d的整株增加质量307·48～399·16g·plant-1,显著大于基质栽培;水培时金琥根系长势良好,具有较强的分生能力,根系鲜样质量、干样质量、根活力、总根长和总根表面积均显著大于基质栽培,其增加率分别达到114·6%、43·3%、38·1%、460·7%和246·4%。淹水环境使金琥根系的解剖结构发生改变,根径显著变小(由基质栽培的0·83mm减小至0·51mm),皮层细胞层数变少,细胞间隙增大,中柱通气组织较发达,有利于根系在水培条件下进行呼吸及吸收和运输养分与水分。因此,静止水培是快速培育金琥的有效栽培技术。

缺铁黄瓜地上部对根系适应性反应的调节

用营养液培养方法研究了黄瓜地上部对根系缺铁适应性反应的调节。缺铁导致植株根系 Fe^(3+)还原酶活性明显增加。缺铁处理的同时分别切去茎尖、茎尖及2片子叶或茎尖及第一片真叶,均不能抑制根系Fe^(3+)还原酶活性的增加。但缺铁使植株各组织中铁含量明显减少,韧皮部汁液中铁浓度也明显降低,相反蔗糖浓度显著增加。韧皮部汁液中铁浓度降低可能与根系适应性反应的调节有关,向根中增加碳水化合物的供应为还原酶活性的增加提供了能源。

园林植物磷胁迫下根系适应性研究

目的以不同基因型园林植物品种为试材,对其在磷胁迫条件下的总根长、最长根长、根表面积、根体积和根尖数进行比较研究,探究园林植物磷高效利用的主要根系及根际过程。方法采用一元二次方程拟合的方法,对不同基因型园林植物品种采取P10、P50、P200的供磷水平,分析不同供磷水平下的根系性状、根性状、冠表现特点及磷吸收量。结果园林植物根系形态及根际特征变化的磷含量在一定范围内有良好的线性关系。结论土壤有效磷浓度与园林植株地上部磷吸收量呈极显著负相关,与园林植株根部磷吸收量、全株磷吸收量、磷吸收效率呈极显著正相关。

植物真菌性根病及其生态防治

根据土壤中植物病原真菌的生物学习性,提出了植物根部病害的生态防治方法。

Organic Acids Secreted from Plant Roots under Soil Stress and Their Effects on Ecological Adaptability of Plants

[Objective] In this study,the secretion of organic acids from plant roots under soil nutrient and water stress and the effects of organic acids on ecological adaptability of plants were investigated,which provided theoretical basis for improving the adaptability of plants to a variety of stress conditions.The results showed that,under nutrient and water stress,the content of organic acids secreted from plant roots increased significantly as a common active adaptive response.Organic acids could improve the activities of a variety of antioxidant enzymes,contents of osmotic regulatory substances,contents of chlorophyll and photosynthesis levels,promote nutrient absorption and transportation in plants,and ultimately contribute to plant growth and biomass accumulation,reduce the toxicity of stress conditions to plants and improve the stress resistance and adaptability of plants.

Drought adaptability of phreatophytes:insight from vertical root distribution in drylands of China

Aims The vertical distribution of plant roots is a comprehensive result of plant adaptation to the environment.Limited knowledge on fine vertical root distributions and complex interactions between roots and environmental variables hinders our ability to reliably predict climatic impacts on vegetation dynamics.This study attempts to understand the drought adaptability of plants in arid areas from the perspective of the relationship between vertical root distribution and surroundings.Methods By analyzing root profiles compiled from published studies,the root vertical profiles of two typical phreatophytes,Tamarix ramosissima and Populus euphratica,and their relationships with environmental factors were investigated.A conceptual model was adopted to link the parameter distribution frequency with plant drought adaptability.Important Findings The strong hydrotropism(groundwater-dependent)and flexible water-use strategy of T.ramosissima and P.euphratica help both species survive in hyperarid climates.The differences in the developmental environments between T.ramosissima and P.euphratica can be explained well by the different distribution characteristics of root profiles.That is,higher root plasticity helps T.ramosissima develop a more efficient water-use strategy and therefore survive in more diverse climatic and soil conditions than P.euphratica.We conclude that the higher variation in root profile characteristics of phreatophytes can have greater root adaptability to the surroundings and thus wider hydrological niches and stronger ecological resilience.The inadequacy of models in describing root plasticity limits the accuracy of predicting the future response of vegetation to climate change,which calls for developing process-based dynamic root schemes in Earth system models.