Due to the hidden nature of roots in the soils, it is more challenging to investigate their resistance traits and defense responses as compared to those of the aerial organs. At the same time, it is self-evident that ...Due to the hidden nature of roots in the soils, it is more challenging to investigate their resistance traits and defense responses as compared to those of the aerial organs. At the same time, it is self-evident that root health is fundamental to a plant’s entire life and productivity. It is also easily conceivable that root function, physiology, morphology, and architecture are constantly impacted by the complex soil environment including both biotic and abiotic factors. This report summarizes and updates the challenges and progress in evaluating resistance responses of apple root to infection from a necrotrophic oomycete pathogen, Pythium ultimum. Several obstacles impede the progress of investigating apple root resistance traits including the difficulties of direct and real-time evaluation and the lack of a continuous supply of apple plants for repeated infection assays. Systematic and detailed analyses were made possible by implementing a micropropagation procedure for continuously generating uniform apple plants for repeated infection assays. As a result, an elite panel of apple rootstock germplasm with distinct resistance levels was identified. These apple rootstock genotypes with well-defined resistance levels are the much-needed plant materials for subsequent genomics and transgenics analyses to define the functional roles of specific candidate genes. Careful microscopic examination revealed contrasting necrosis progression patterns between resistant and susceptible genotypes, which shed light on the potential mechanisms underlying resistance traits. Our continuing research will provide a clearer view regarding the genetic elements regulating resistance traits in apple roots to P. ultimum infection.展开更多
The effect of plant growth substance and fertilizer on root formation was studied in a newly planted apple tree (Malm pumila Mill / Malus hupenensis Rhed). The results indicated that urea and IBA ( indole butyric acid...The effect of plant growth substance and fertilizer on root formation was studied in a newly planted apple tree (Malm pumila Mill / Malus hupenensis Rhed). The results indicated that urea and IBA ( indole butyric acid) and sheep dung all increased the total number and activity of new roots and changed the ratio of absorbing root to extensive roots obviously. Urea increased the number of extensive root and decreased the ratio of the root to shoot mostly. IBA lengthened the extensive root and increased the ratio of root to shoot obviously. Sheep dung increased the nu mber of absorbing root and increased the ratio of absorbing root to extensive root, divided new root into many branches, increased the fresh weight of the root and thickened the extensive root. The fresh weight of root increased and the ratio of root to shoot declined after urea was added to sheep dung. Both the ratio of absorbing root to extensive root and root fresh weight was increased after IBA was added to sheep dung, then the ratio of root to shoot had no change obviously.展开更多
文摘Due to the hidden nature of roots in the soils, it is more challenging to investigate their resistance traits and defense responses as compared to those of the aerial organs. At the same time, it is self-evident that root health is fundamental to a plant’s entire life and productivity. It is also easily conceivable that root function, physiology, morphology, and architecture are constantly impacted by the complex soil environment including both biotic and abiotic factors. This report summarizes and updates the challenges and progress in evaluating resistance responses of apple root to infection from a necrotrophic oomycete pathogen, Pythium ultimum. Several obstacles impede the progress of investigating apple root resistance traits including the difficulties of direct and real-time evaluation and the lack of a continuous supply of apple plants for repeated infection assays. Systematic and detailed analyses were made possible by implementing a micropropagation procedure for continuously generating uniform apple plants for repeated infection assays. As a result, an elite panel of apple rootstock germplasm with distinct resistance levels was identified. These apple rootstock genotypes with well-defined resistance levels are the much-needed plant materials for subsequent genomics and transgenics analyses to define the functional roles of specific candidate genes. Careful microscopic examination revealed contrasting necrosis progression patterns between resistant and susceptible genotypes, which shed light on the potential mechanisms underlying resistance traits. Our continuing research will provide a clearer view regarding the genetic elements regulating resistance traits in apple roots to P. ultimum infection.
基金supported by the National Natura Science Foundation of China(No.39600102,30170655).
文摘The effect of plant growth substance and fertilizer on root formation was studied in a newly planted apple tree (Malm pumila Mill / Malus hupenensis Rhed). The results indicated that urea and IBA ( indole butyric acid) and sheep dung all increased the total number and activity of new roots and changed the ratio of absorbing root to extensive roots obviously. Urea increased the number of extensive root and decreased the ratio of the root to shoot mostly. IBA lengthened the extensive root and increased the ratio of root to shoot obviously. Sheep dung increased the nu mber of absorbing root and increased the ratio of absorbing root to extensive root, divided new root into many branches, increased the fresh weight of the root and thickened the extensive root. The fresh weight of root increased and the ratio of root to shoot declined after urea was added to sheep dung. Both the ratio of absorbing root to extensive root and root fresh weight was increased after IBA was added to sheep dung, then the ratio of root to shoot had no change obviously.
