Plant Nitrogen Metabolism: Balancing Resilience to Nutritional Stress andAbiotic Challenges

Plant growth and resilience to abiotic stresses,such as soil salinity and drought,depend intricately on nitrogen metabolism.This review explores nitrogen’s regulatory role in plant responses to these challenges,unveiling a dynamic interplay between nitrogen availability and abiotic stress.In the context of soil salinity,a nuanced rela-tionship emerges,featuring both antagonistic and synergistic interactions between salinity and nitrogen levels.Salinity-induced chlorophyll depletion in plants can be alleviated by optimal nitrogen supplementation;however,excessive nitrogen can exacerbate salinity stress.We delve into the complexities of this interaction and its agri-cultural implications.Nitrogen,a vital element within essential plant structures like chloroplasts,elicits diverse responses based on its availability.This review comprehensively examines manifestations of nitrogen deficiency and toxicity across various crop types,including cereals,vegetables,legumes,and fruits.Furthermore,we explore the broader consequences of nitrogen products,such as N_(2)O,NO_(2),and ammonia,on human health.Understand-ing the intricate relationship between nitrogen and salinity,especially chloride accumulation in nitrate-fed plants and sodium buildup in ammonium-fed plants,is pivotal for optimizing crop nitrogen management.However,prudent nitrogen use is essential,as overapplication can exacerbate nitrogen-related issues.Nitrogen Use Effi-ciency(NUE)is of paramount importance in addressing salinity challenges and enhancing sustainable crop productivity.Achieving this goal requires advancements in crop varieties with efficient nitrogen utilization,pre-cise timing and placement of nitrogen fertilizer application,and thoughtful nitrogen source selection to mitigate losses,particularly urea-based fertilizer volatilization.This review article delves into the multifaceted world of plant nitrogen metabolism and its pivotal role in enabling plant resilience to nutritional stress and abiotic challenges.It offers insights into future directions for sustainable agriculture.

Evaluation of Various Mango Varieties against the Infection Dynamics of Powdery Mildew (<i>Oidium mangiferae</i>Bert.)

Mango (Mangifera indica L: Anacardiaceae) is regarded as the most liked fruit in tropical and sub-tropical regions of the world. Powdery mildew of mango caused by Oidium mangiferae Bert. is one of the major plant pathological constraints in growing healthy mango orchards. The apparent symptoms of the disease occurred on young tissues of all parts of flowers, leaves and fruits. Severe blossom infection could result in complete damage to fruit;flower failed to open and drop off from the inflorescence. The inflorescence revealed a pattern of disease from tip to downward and showed itself by the emergence of wefts of white mycelium on the affected parts. Twenty-five mango varieties i.e. Langra, Dusehri, Ratole No.12, Fajri, Sindhri, Chaunsa Samar Bahisht, Anwar ratole, Neelam, Yakta, Tota Pari, Sensation, Saroli, Malda, Ghulab e Khas, Chaunsa Black, Chaunsa white, Anmol, Almas, Shan e Ali, Shan e Mustafa, Mahmood Khan, Armughan, Zafaran, Malda Late and Early Gold were evaluated through the observation of symptoms on young inflorescence to determine the disease incidence, disease severity index and average yield of fruit. The study was carried out in a randomized compete block design with twenty-five treatments and three replications. The mango varieties presented different performance in relation to powdery mildew incidence and could be categorized into eight groups. Maximum disease incidence was observed (33.33%, 26.66% and 26.66%, 26.66%) on Dusehri, Chaunsa Samar Bahisht, Malda and Ratole No.12 respectively and minimum disease incidence was (3.66% and 3.66%) noted on Almas and Sensation. These two varieties showed to be tolerant against the disease. It might be concluded that the presence or absence of symptoms caused by the powdery mildew had no such effect on the fruit yield of the mango cultivars.