Ksouri Riadh, Debez Ahmed, Mahmoudi Henda, Ouerghi Zeineb, Gharsalli Mohamed, Lachaâl Mokhtar
Laboratoire d'Adaptation des Plantes aux Stress Abiotiques, Centre de Biotechnologies de la Technopole de Borj-Cédria, BP 901, 2050 Hammam-Lif, Tunisia.
Plant Physiol Biochem. 2007 May;45(5):315-22. doi: 10.1016/j.plaphy.2007.03.014. Epub 2007 Mar 15.
Morpho-physiological responses to bicarbonate-induced Fe deficiency were investigated in five Vitis vinifera L. Tunisian varieties (Khamri, Blanc3, Arich Dressé, Beldi, and Balta4). One-month-old woody cuttings were cultivated for 85days on a free calcareous soil irrigated with tap water containing increasing bicarbonate levels (0, 4, 8, 12, and 16mM NaHCO(3)). After this screening, a second experiment compared root biochemical responses of two contrasting genotypes (tolerant-sensitive) dealing with bicarbonate-induced iron deprivation (20microM Fe+/-10mM HCO(3)(-)) for 75days. Using morpho-physiological criteria, grapevine tolerance to HCO(3)(-)-induced Fe shortage appeared to be genotype-dependent: Balta4 and Beldi varieties showed the highest leaf-chlorosis score (especially at the extreme HCO(3)(-) levels), in contrast to Khamri variety. Growth parameters (shoot height, total leaf area, leaf number, and biomass production) as well as juvenile leaf chlorophyll content were also differently affected depending on both genotype and bicarbonate dose. At 16mM HCO(3)(-), Khamri was the less sensitive variety, contrasting with Balta4. On the other hand, chlorophyll content correlated positively with HCl-extractible Fe content of the juvenile leaves, suggesting that the grapevine response to iron deficiency may partly depend on to the plant ability to adequately supply young leaves with this element. Root biochemical responses revealed a relatively higher root acidification capacity in Khamri (tolerant) under Fe-deficiency while no significant changes occurred in Balta4 (sensitive). In addition, Fe(III)-reductase and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) activities were strongly stimulated by Fe-deficiency in Khamri, while remaining constant in Balta4. These findings suggest that biochemical parameters may constitute reliable criteria for the selection of tolerant grapevine genotypes to iron chlorosis.
研究了五个突尼斯酿酒葡萄品种（Khamri、Blanc3、Arich Dressé、Beldi和Balta4）对碳酸氢盐诱导的缺铁的形态生理反应。将一个月大的硬枝插条在自由钙质土壤上培养85天，用含有递增碳酸氢盐水平（0、4、8、12和16mM NaHCO₃）的自来水灌溉。经过这次筛选后，第二个实验比较了两种对比基因型（耐缺铁-缺铁敏感型）在处理碳酸氢盐诱导的铁缺乏（20μM铁±10mM HCO₃⁻）75天后的根系生化反应。使用形态生理标准，葡萄对HCO₃⁻诱导的铁短缺的耐受性似乎取决于基因型：与Khamri品种相比，Balta4和Beldi品种表现出最高的叶黄化评分（尤其是在极端HCO₃⁻水平下）。生长参数（茎高、总叶面积、叶片数量和生物量生产）以及幼叶叶绿素含量也因基因型和碳酸氢盐剂量的不同而受到不同影响。在16mM HCO₃⁻时，Khamri是最不敏感的品种，与Balta4形成对比。另一方面，叶绿素含量与幼叶中HCl可提取的铁含量呈正相关，这表明葡萄对缺铁的反应可能部分取决于植物向幼叶充分供应这种元素的能力。根系生化反应表明，在缺铁条件下，Khamri（耐缺铁型）的根系酸化能力相对较高，而Balta4（缺铁敏感型）没有显著变化。此外，缺铁强烈刺激了Khamri中Fe(III)还原酶和磷酸烯醇丙酮酸羧化酶（PEPC，EC 4.1.1.31）的活性，而在Balta4中保持不变。这些发现表明，生化参数可能构成选择耐缺铁性葡萄基因型的可靠标准。
