Oustric Julie, Herbette Stéphane, Morillon Raphaël, Giannettini Jean, Berti Liliane, Santini Jérémie
CNRS, Équipe de Biochimie et Biologie Moléculaire du Végétal, UMR 6134 SPE, Université de Corse, Corsica, France.
UCA, INRAE, PIAF, Clermont-Ferrand, France.
Front Plant Sci. 2021 Apr 8;12:634237. doi: 10.3389/fpls.2021.634237. eCollection 2021.
Nutrient deficiency, in particular when this involves a major macronutrient (N, P, and K), is a limiting factor on the performance of plants in their natural habitat and agricultural environment. In the citrus industry, one of the eco-friendliest techniques for improving tolerance to biotic and abiotic stress is based on the grafting of a rootstock and a scion of economic interest. Scion tolerance may be improved by a tetraploid rootstock. The purpose of this study was to highlight if tolerance of a common clementine scion (C) ( Hort. ex Tan) to nutrient deficiency could be improved by several diploid (2×) and their tetraploid (4×) counterparts citrus genotypes commonly used as rootstocks: Trifoliate orange × Cleopatra mandarin (C/PMC2x and C/PMC4x), Carrizo citrange (C/CC2x and C/CC4x), Citrumelo 4475 (C/CM2x and C/CM4x). The allotetraploid FlhorAG1 (C/FL4x) was also included in the experimental design. The impact of nutrient deficiency on these seven scion/rootstock combinations was evaluated at root and leaf levels by investigating anatomical parameters, photosynthetic properties and oxidative and antioxidant metabolism. Nutrient deficiency affects foliar tissues, physiological parameters and oxidative metabolism in leaves and roots in different ways depending on the rootstock genotype and ploidy level. The best known nutrient deficiency-tolerant common clementine scions were grafted with the doubled diploid Citrumelo 4475 (C/CM4x) and the allotetraploid FlhorAG1 (C/FL4x). These combinations were found to have less foliar damage, fewer changes of photosynthetic processes [leaf net photosynthetic rate ( ), stomatal conductance ( ), transpiration (E), maximum quantum efficiency of PSII ( / ), electron transport rate (ETR), ETR/ ], and effective quantum yield of PSII [(II)], less malondialdehyde accumulation in leaves and better functional enzymatic and non-enzymatic antioxidant systems. Common clementine scions grafted on other 4× rootstocks did not show better tolerance than those grafted on their 2× counterparts. Chromosome doubling of rootstocks did not systematically improve the tolerance of the common clementine scion to nutrient deficiency.
营养缺乏，尤其是涉及主要常量营养素（氮、磷和钾）时，是植物在其自然栖息地和农业环境中生长表现的限制因素。在柑橘产业中，提高对生物和非生物胁迫耐受性的最环保技术之一是基于嫁接砧木和具有经济价值的接穗。四倍体砧木可能会提高接穗的耐受性。本研究的目的是探讨常用的二倍体（2x）及其四倍体（4x）柑橘基因型砧木：枳橙×埃及青柠（C/PMC2x和C/PMC4x）、卡里佐枳橙（C/CC2x和C/CC4x）、Citrumelo 4475（C/CM2x和C/CM4x）是否能提高普通克莱门氏小柑橘接穗（C）（Hort. ex Tan）对营养缺乏的耐受性。异源四倍体FlhorAG1（C/FL4x）也包含在实验设计中。通过研究解剖学参数、光合特性以及氧化和抗氧化代谢，在根和叶水平评估营养缺乏对这七种接穗/砧木组合的影响。营养缺乏对叶组织、生理参数以及叶和根中的氧化代谢有不同影响，这取决于砧木基因型和倍性水平。最知名的耐营养缺乏普通克莱门氏小柑橘接穗与加倍的二倍体Citrumelo 4475（C/CM4x）和异源四倍体FlhorAG1（C/FL4x）嫁接。发现这些组合的叶损伤较小，光合过程[叶片净光合速率（ ）、气孔导度（ ）、蒸腾作用（E）、PSII最大量子效率（ / ）、电子传递速率（ETR）、ETR/ ]和PSII有效量子产率[（II）]变化较少，叶片中丙二醛积累较少，并且具有更好的功能性酶促和非酶促抗氧化系统。嫁接在其他4x砧木上的普通克莱门氏小柑橘接穗并未表现出比嫁接在其2x对应砧木上的接穗更好的耐受性。砧木的染色体加倍并没有系统地提高普通克莱门氏小柑橘接穗对营养缺乏的耐受性。
