Plants exhibit higher leaf-to-root ratios (L/R) and lower leaf nitrogen content (N(area)) in low-light than in high-light environments, but an ecological significance of this trait has not been explained from a whole-plant perspective. This study aimed to theoretically and experimentally demonstrate whether these observed L/R and N(area) are explained as optimal biomass allocation that maximize...

to evaluate the effect of time and level of nitrogen application on quantity and quality of two carrot varieties, an experiment was carried out in the framework of a 4×3×2 factorial and based upon a randomized complete block design of three replications. the levels of 25, 50, 75 and 100 kg / ha of nitrogen fertilizer were investigated within 3 applied times, namely: simultaneous with bed prepar...

nitrogen (n) affects adversely the tobacco yield quantity and quality as it increases yield, chlorine and nicotine contents, but decrease potassium content. this experiment was aimed at optimization of (the balance between) n concentration in leaf, stem and root to increase both yield quantity and quality (high potassium, low chlorine and medium nicotine contents) using artificial neural networ...

Paraburkholderia phymatum belongs to the β-subclass of proteobacteria. It has recently been shown to be able to nodulate and fix nitrogen in symbiosis with several mimosoid and papilionoid legumes. In contrast to the symbiosis of legumes with α-proteobacteria, very little is known about the molecular determinants underlying the successful establishment of this mutualistic relationship with β-pr...

The effect of different nitrogen levels on plant growth, phenol content, antioxidant and Nitrate reductase )NR) activity of cucumber (Cucumis sativus cv. Super) inoculated with mycorrhiza­ was studied. A factorial experiment based on a completely randomized design (CRD) with 6 replicates was designed. Treatments were three levels of nitrogen (NO3-50, NO3-75 and NO...

dianchi lake is one of the most three seriously eutrophic lakes in china. in the present study, the phosphorus (p) and nitrogen (n) fractions in 37 surface sediments samples collected in the dianchi lake were investigated. the total phophorus (tp) in sediments was divided into two parts: inorganic p (ip) and residual p (res-p). the results showed that the total phosphorus content in surface se...

There are complex inter- and intra-relations between regressors (independent variables) andyield quantity (W) and quality (Q) in tobacco. For instance, nitrogen (N) increases W butdecreases Q; starch harms Q but soluble sugars promote it. The balance between (optimizationof) regressors is needed for simultaneous increase in W and Q components [higher potassium(K), medium nicotine and lower chlo...

Many external and internal studies in based on the relevant literature and consult to tobacco experts,based on the experimental research of the years between 2004 and 2005, the basic model of soil-N of distribution was developed after analysising the content of nitrogen in the whole plant of tobacco. The model is designed to simulate dynamically absorption and distribution of nitrogen for tobac...

Ectomycorrhiza (ECM) plays an important role in plant nitrogen (N) nutrition and regulates plant responded to climate warming. We conducted a field experiment in a natural forest and a plantation in the eastern Tibetan Plateau to estimate the warming effects of open-top chambers (OTC) on ECM and N nutrition of Picea asperata seedlings. Four-year warming significantly decreased ECM colonization,...

sugarcane, which has high water requirements, is grown in khuzestan province (iran). climate and optimizing the use of water is very important to sustainable cultivation of sugarcane. studies of water requirements for sugar cane in khuzestan show that in parts of sugarcane agro-industry, the water applied is more than the actual water requirement of the plant. the present study was conducted to...