Inhibition Of Photosynthesis In Plants Research Articles

Comparative Transcriptome Analysis Reveals the Molecular Basis of Brassica napus in Response to Aphid Stress.

Rapeseed is a globally important economic crop that can be severely impacted by aphids. However, our understanding of rapeseed resistance to aphid stress is very limited. In this study, we analyzed the resistance characteristics of the low aphid-susceptible variety APL01 and the highly aphid-susceptible variety Holly in response to aphid stress. APL01 had a more significant inhibitory effect on aphid proliferation compared with Holly during the early stage of inoculation, whereas Holly showed stronger tolerance to aphid stress compared with APL01 during the later stage of inoculation. Through transcriptome, physiological, and gene expression analyses, it was revealed that chitinase activity, catalase activity, calcium signal transduction, and activation of systemic acquired resistance might be involved in aphid resistance in B. napus. The degree of inhibition of photosynthesis in plants under aphid stress directly determines the tolerance of B. napus to aphid stress. Furthermore, four promising candidate genes were screened from eight genes related to rapeseed response to biotic stress through RT-qPCR analysis of gene expression levels. These research findings represent an important step forward in understanding the resistance of rapeseed to aphid stress and provide a solid foundation for the cloning of genes responsible for this resistance.

INFLUENCE OF DIFFERENT DOSES OF SEWAGE SLUDGE ON THE MORPHOLOGICAL-PHENOLOGICAL FEATURES OF AMARANTH (AMARANTHUS CRUENTUS)

Due to the fact that amaranth belongs to type C4 plants, the process of photosynthesis of amaranth differs from other plants. It absorbs carbon dioxide more actively than C3 plants and effectively enriches the air with oxygen. In this regard, decorative amaranth varieties should be used as a natural filter in urban environments with a high carbon dioxide content. In addition, decorative amaranth varieties have a unique leaf and flower shape. The color of amaranth can be yellow, red, green, crimson, three colors; the shape of the leaves is oval, curly; inflorescences are also distinguished by their varied beauty. Soil fertility, temperature and humidity are great importance for the normal development for any plant. In the absence of one of the above factors, the quality of life of the plant will decrease. Lack of nutrients in the soil, unfavorable weather, l ack of moisture leads to inhibition of photosynthesis in plants, a decrease in biomass, and decrease disease resistance. During our research, the sludge of municipal wastewater was used as fertilizer. Slud ge accumulates on landfills as waste, giving off an unpleasant odor and negatively affecting the environment. However, this hazardous waste can be recycled and obtained organic fertilizers for urban landscaping or soil reclamation of disturbed lands. The results of the study showed that 10 t / ha of sewage sludge is the most positive impact on the growth of amaranth, the increase in total biomass, stem length and flower were noted . At this length of the stem of the plant increased by 77%, the length of the inflorescence - in 2.2 times, the mass of inflorescences - in 1.8 times, the biomass of the plant before flowering - in 2.1 times compared to the control.

Leaf physiological impedance and elasticity modulus in Orychophragmus violaceus seedlings subjected to repeated osmotic stress

Leaf water status is always influenced by plant growth and environment and dynamically changes over time. Rapid measurement of leaf physical characteristics helps to timely determine the plant water needs, in order to prevent inhibition of photosynthesis in plants and improve irrigation water-use efficiency (WUE) under water deficit conditions. The present study determined leaf electrophysiological and mechanical properties, water content (LWC), water potential (ΨL), carbonic anhydrase (CA) activity, net photosynthesis, and re-watering WUE (WUER) in relation to osmotic stress and following drought hardening in Orychophragmus violaceus seedlings. The study established a coupling model between gripping force and physiological impedance according to the Nernst equation, and the leaf water dissipation rate (LWDR) was defined and determined. Changes of cell stiffness and LWDR altered the intracellular water status, which affected the photosynthetic capacity and WUER. Photosynthesis was inhibited by the 40 g L−1 PEG (polyethylene glycol) treatment due to the reduction of intracellular water, and leaf cells were severely damaged at the higher, 80 g L‒1 PEG. Plants transferred from 20 to 10 g L‒1 PEG had the highest WUER. We have found that the physiological impedance provides more reliable information of plant water status compared with ΨL, which can help improve the irrigation WUE.

Relationships among Rhizosphere Oxygen Deficiency, Root Restriction, Photosynthesis, and Growth in Baldcypress (Taxodium Distichum L.) Seedlings

Seedlings of baldcypress (Taxodium distichum L.) grown in sealed containers containing nutrient solution were subjected to root-zone oxygen deficiency, physical restriction, and the combined stresses in a greenhouse. After six weeks of treatments (Phase I), half of the plants were harvested. The remaining half were allowed to continue (Phase II) under various treatments except plants that had restricted roots were freed thus allowing free expansion of roots into the nutrient solution. Oxygen deficiency and root physical restriction inhibited plant gas exchange parameters. Net photosynthetic rate (PN) was significantly higher in aerated unrestricted root (AUR) plants than in aerated root restricted (AR) plants and in anaerobic root unrestricted (FUR) plants than in anaerobic root restricted (FR) plants. After Phase I, FUR plants' shoot and root biomasses were 57.0 and 30.6 % lower than those of AUR plants, and AUR plants showed 3.3 and 3.8 times greater shoot and root biomasses than the AR plants, respectively. During Phase II, PN recovered rapidly in plants under aerated conditions, but not in plants under anaerobic conditions. The removal of physical root restriction under both aerated and anaerobic conditions resulted in rapid shoot and root growth in seedlings. Hence, root restriction or root-zone anaerobiosis, reductions in plant gas exchange, and biomass production in baldcypress were closely interrelated. In addition, root release from restriction was related to the regain of photosynthetic activity and biomass growth. The results support the previously proposed source-sink feed-back inhibition of photosynthesis in plants subjected to root-zone oxygen deficiency or physical restriction.

Non‐uniform stomatal closure induced by water stress causes putative non‐stomatal inhibition of photosynthesis

summaryThe partial pressure of intercellular CO2 derived from gas exchange data for water‐stressed grapevine (Vitis vinijera L.), oleander (Nerium oleander L.) and red‐flowering gum (Eucalyptus ficifolia F. Muell.) does not indicate the actual average intercellular CO2 of the leaf. This can be determined from chlorophyll fluorescence signals and modelled from conventional gas exchange information. Water stress increases endogenous levels of abscisic acid and the leaves respond in a similar manner to that observed when exogenous abscisic acid is applied. Autoradiograms show that water stress results in non‐uniform gas exchange over small areas of the leaf. Non‐uniform stomatal closure can account for the apparent non‐stomatal inhibition of photosynthesis in plants experiencing water stress.