Drought Stress Effects and Ways for Improving Drought Tolerance in Impatiens walleriana Hook.f.—A Review

Drought is one of the main abiotic stresses affecting plant growth and development. Reduced plant yield and quality are primarily caused by the reductions in photosynthesis, mineral uptake, metabolic disorders, damages from the increased production of reactive oxygen species, and many other disruptions. Plants utilize drought resistance mechanisms as a defense strategy, and the systems’ activation is dependent upon several factors, including plant genotype, onthogenesis phase, drought intensity and duration, and the season in which the drought occurs. Impatiens walleriana is a worldwide popular flowering plant recognized for its vibrant flower colors, and is an indispensable plant in pots, gardens and other public areas. It prefers well-draining, moisturized soil, and does not perform well in overly dry or waterlogged conditions. Consequently, inadequate water supply is a common problem for this plant during production, transportation, and market placement, which has a substantial impact on plant performance overall. This review article outlines certain features of morphological, physiological, and molecular alterations induced by drought in ornamental, drought-sensitive plant species I. walleriana, as well as research carried out to date with the aim to improve the drought tolerance. Stress proteins aquaporins and dehydrins, whose molecular structure was described for the first time in this plant species, are highlighted specifically for their role in drought stress. Furthermore, the effective improvement of drought tolerance in I. walleriana by exogenous application of Plant Growth Regulators and Plant Growth-Promoting Bacteria is discussed in detail. Finally, this review can provide valuable insights for improving plant resilience and productivity in the face of water scarcity, which is critical for sustainable agriculture and horticulture.