Original Research Article

IMPACT OF TEMPERATURE STRESS ON THE FUNCTIONAL EFFICIENCY OF Brassica napus SEEDLINGS

HARPREET KAUR, JAGMANDEEP SINGH, KULWINDER KAUR

Asian Journal of Plant and Soil Sciences, Page 18-23

The aim of present study was to explore the deteriorating impact of temperature stress on morpho-physiological attributes and photosynthetic pigments of Brassica napus L. seedlings exposed to oxidative stress caused by high (40°C) and low (4°C) temperature. For this, experiments were carried out at the Senior Laboratory, P.G. Department of Botany, Khalsa College, Amritsar. Effect of different degrees of temperature (4°C and 40°C) on double distilled water primed seedlings of B. napus L. was investigated. Different degrees of temperatures used in present study showed diverse effect on shoot, root length and light quenching pigments such as chlorophyll a, chlorophyll b, total chlorophyll and total carotenoids content.  Low temperature (4°C) treatment depreciate all aspects of growth and physiology by diminishing photosynthetic pigments and altering the carbon makeup negatively as compared to control, Although high temperature treatment also deteriorated all the attributes of growth, physiological and biochemical components as compared to control and low temperature treated seedlings. In conclusion both low and high temperature (4°C & 40°C) decrease the amelioration of morphophysiological components, reallocation of nutrients and modulation of photosynthetic machinery.

Review Article

REVIEW ON WEED MANAGEMENT PRACTICES IN WHEAT (Triticum spp.)

ABEBE MISGANAW, GENET AYALEW

Asian Journal of Plant and Soil Sciences, Page 1-8

Wheat (Triticum spp.) is a cereal grain, originally from the Levant region of the Near East but now cultivated worldwide. It is in the kingdom Plantae and family poaceae. Ethiopia is one of the largest recipients of food aid in Africa. Achieving the desired wheat production is difficult due to many production constraints such as weed infestation. Weed infestation is one of the major biotic constraints in wheat production. Wheat is infested with diverse type of weed flora, which can be grassy and broadleaf, as it is grown under diverse agro climatic conditions, different cropping sequence and tillage and irrigation regimes. The yield losses due to weeds vary depending on the weed species, their density and environmental factors. The yield loss due to weed infestation can be reduced by using different weed management practices such as cultural, mechanical, biological and chemical weed control methods. The objective of this seminar paper is to review recent research finding on weed management practices in wheat. To feed the growing population there is a need to increase the wheat production without much dependence on chemicals like fertilizers and herbicides which have unpredictable harmful effects on environment and human health. There is a need to improve weed management techniques for better crop production. Improved herbicide formulations with low or no toxicity except for the target weeds seems to be the demand of near future in agricultural sector.

Review Article

CYANOBACTERIA ACT AS NITROGEN-FIXING ORGANISMS: A REVIEW

NEERAJ PANDEY, SHALLU .

Asian Journal of Plant and Soil Sciences, Page 9-17

Cyanobacteria, also known as Cyanophyta, are a phylum of bacteria that have chlorophyll and phycobiliprotein and can fasten carbon like plants through photosynthesis of oxygen evolution. Nitrogen fixation is a prevalent phenomenon exhibited by many organisms to fix the environmental nitrogen source in a usable form. Free-living N2-fixing cyanobacteria and Azolla (a symbiotic combination of water fern Azolla, Nostoc and Anabaena) are widely used as organic fertilizer for rice as well as corn, soybean, groundnuts. Under nitrogen limitation, a portion of the cyanobacteria can recognize a particular cell called heterocyst that offers an ideal microoxic climate for the legitimate working of oxygen-sensitive enzyme nitrogenase. Nitrogenase complex is engaged in N2 fixation in heterocystous cyanobacteria which is also followed by hydrogen manufacturing. A cyanobacteria possesses nif genes among multiple such species, which can be organized by polymerase chain reaction at the molecular level. Nitrogen control in cyanobacteria is mediated by Ntc A, a transcriptional regulator that belongs to the activator of the catabolite factor and is therefore distinct from a well-characterized Ntr scheme. This study is an attempt to recruit useful knowledge about the characteristics of cyanobacteria and their possible role in addressing the future wellbeing of the planet's agricultural and environmental challenges.