Cytogenetic polymorphism of seed progeny of walnut (Juglans regia L.) during introduction in the Central Chernozem Region

Abstract

We studied the cytogenetic characteristics of the seed progeny of the walnut (Juglans regia L.) trees introduced to and grown within the territory of the Central Russian Upland. Three seedling groups with polymorphic cytogenetic characteristics were revealed: mutable (with a high level of pathological mitoses), low mutable (with a low level of cytogenetic disturbances), and intermediate groups. Cytogenetic characteristics (mitotic activity, parts of cells at various stages of mitosis, the level and spectrum of pathological mitoses, sizes of nucleoli and the spectrum of their types, the occurrence of cells with a persistent nucleolus in the stages of meta-, ana-, and telophase) in each of the selected groups were described; homeostatic mechanisms at the cellular level were discussed. The sizes of polymorphic groups were established. The small number of seedlings with a high level of cytogenetic disturbances (7.5%) and the predominance of seedlings with medium (70%) and low (22.5%) values of pathological mitoses indicated a high degree of adaptation of the introduced walnut mother trees to the environmental conditions of the Central Russian Upland. Predictors for assigning any seedling to one of the selected model groups (mutable or low mutable) were established using ROC analysis methods. The obtained data on the qualitative and quantitative polymorphism of cytogenetic characteristics can be used for the development of recommendations for improving the system of seed production and the selection of new forms of walnut in the Central Chernozem Region.

Assessing the Effect of Plant Biostimulants and Nutrient-Rich Foliar Sprays on Walnut Nucleolar Activity and Protein Content (Juglans regia L.)

“…However, Ref. [44] also reported a reduced mitotic index on root meristematic cells of walnuts. The small size of the Juglans spp.…”

“…Therefore, the cytogenetic monitoring of dividing mesophyll or root meristem cells, which are plant organs exposed to stressful conditions, constitutes a suitable and fast approach to selecting adequate foliar treatments [24,25] or the most stress-tolerant genotypes [26,27,33]. Moreover, such studies can also highlight cytotoxicity, which is common when biostimulants or fertilisers are used in dosages above the manufacturer's recommendation [35,[37][38][39][40][41][42][43][44]. Despite the common assumption held by producers of fertilisers and different authors that boron stimulates growing tissues [19,42] as a consequence of the enhancement of cell division, the leaf mitotic index was low despite collecting young leaves in all treatments.…”