scholarly journals Effect of Paclobutrazol Treatment on Some Leaf Physiological and Biochemical Characteristics of Rejuvenated Coffee (Coffea arabica L.) Trees

2016 ◽  
pp. 74-82
Author(s):  
Arsenio Ramos
Keyword(s):  
Chlorophyll Content ◽  
Transpiration Rate ◽  
Net Photosynthesis ◽  
Physiological And Biochemical Characteristics ◽  
Co Concentration ◽  
Rate Of Photosynthesis ◽  
Physiological And Biochemical ◽  
Coffea Arabica L ◽  
Treatment Application ◽  
Leaf N

Rejuvenation pruning has been proven effective in bringing back vigor and productivity of old coffee trees. The effectiveness of the present rejuvenation techniques however could be probably enhanced by the application of tree growth regulators with known reinvigorating or tree health enhancing effect such as Paclobutrazol but has not been tried so far. The present study aimed to evaluate some physiological and biochemical responses of the rejuvenated coffee trees to timing and level of PBZ application prior to cutting. Plants applied with PBZ 2 months prior to pruning had higher leaf internal CO concentration compared to those applied 1 month prior to 2 pruning. Net photosynthesis, transpiration rate, PAR/LAI, chlorophyll content, and leaf N, P, K, Ca and Mg contents did not differ with time of PBZ treatment. Application of 0.5-1.0 g a.i. PBZ per meter canopy span significantly increased transpiration rate, internal COconcentration and 2 chlorophyll content but did not affect the rate of photosynthesis, PAR/LAI, leaf N, P, K, Ca and Mg contents.

scholarly journals Arbuscular Mycorrhizal Fungi Inoculation as a Climate Adaptation Strategy for Establishment of Swietenia macrophylla King. Seedlings

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 488
Author(s):  
Lakshmy J. Rajan ◽  
Santhoshkumar A. V. ◽  
Surendra Gopal K. ◽  
Kunhamu T. K.
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Arbuscular Mycorrhizal Fungi ◽  
Water Potential ◽  
Chlorophyll Content ◽  
Transpiration Rate ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Tree Seedlings ◽  
Rate Of Photosynthesis

Research Highlights: Drought stress significantly decreased the performance of seedlings in the nursery. Seedlings inoculated with Claroideoglomus etunicatum is recommended to produce superior planting stock of mahogany seedlings with better drought resistance in the nursery. Background and Objectives: With numerous intense droughts across tropical regions due to climate change, it is crucial to understand effects of drought stress on tree seedlings to improve crop management practices and avoid failures on large scale planting. Swietenia macrophylla, a commercial timber species in India, is poorly studied in relation to its management including physiological responses to various environmental stresses. Arbuscular mycorrhizal fungi (AMF) is known to improve performance of tree seedlings under drought conditions and produce quality planting stock in nursery. This study aims to understand the responses of mahogany seedlings under different levels of drought stress when inoculated with three types of AMF, namely Funneliformis mosseae, Claroideoglomus etunicatum, and Rhizophagus intraradices. Materials and Methods: The experiment is conducted in pot culture using a factorial completely randomized design. Different irrigation regimes were applied at 100, 80, 60, and 40 percentage of weekly cumulative evapotranspiration. The seedlings were tested for biometric, physiological, and mycorrhizal parameters periodically. Results: Physiological attributes such as rate of photosynthesis, stomatal conductance, transpiration rate, chlorophyll content, and water potential were found to be higher in the daily irrigated (control) seedlings. Performance of the seedlings were poorest in the least irrigated treatment. It was apparent that inoculated seedlings performed better than the non-inoculated ones. Conclusions: Among the three different AMF species used, C. etunicatum was found to be the most beneficial and suitable for the young mahogany seedlings. These seedlings also recorded higher root colonization percentage and total spore count in the rhizosphere soils. Seedlings inoculated with C. etunicatum showed positive influence on rate of photosynthesis, stomatal conductance, transpiration rate, chlorophyll content, relative growth rate (RGR) and water potential of seedlings.

scholarly journals Cold Acclimation Affects Physiological and Biochemical Characteristics of Betula platyphylla S. under Freezing Stress

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1777
Author(s):  
Faujiah Nurhasanah Ritonga ◽  
Siyu Yan ◽  
Song Chen ◽  
Syamsudin A. Slamet ◽  
Laswi Irmayanti ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Cold Acclimation ◽  
Chlorophyll Content ◽  
Tree Species ◽  
Freezing Stress ◽  
Betula Platyphylla ◽  
Biochemical Characteristics ◽  
Physiological And Biochemical Characteristics ◽  
Before And After ◽  
Physiological And Biochemical

Cold and freezing stress is one of the most harmful environmental stresses, especially in temperate and subtropical areas, that adversely affects plant growth, development, and yield production. Betula platyphylla Sukaczev, also known as white birch, is one of the most valuable, important, and widely distributed tree species in East Asia. This study explored the effects of cold acclimation (CA) in reducing the destructive effect of freezing stress in B. platyphylla seedlings. We measured the physiological and biochemical characteristics of B. platyphylla seedlings, such as chlorophyll content, electrolyte leakage (EL), malondialdehyde (MDA), antioxidant enzymes (such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), and proline content before and after freezing stress to observe the contribution of CA in reducing the detrimental effects of freezing stress. The results showed that CA increased physiological and biochemical characteristics of B. platyphylla seedlings before and after freezing stress, except for chlorophyll content. Antioxidant enzymes were significantly positively correlated with proline, MDA, and EL content, and negatively correlated with chlorophyll content. Moreover, histochemical detection (H2O2 and O2−) and cell death were revealed to be induced by cold stress in B. platyphylla seedlings. Furthermore, it was revealed that increased time and decreased temperature of the CA process significantly influenced the physiological and biochemical parameters. Overall, the CA process significantly reduced the detrimental effects of freezing stress compared to the control treatment in B. platyphylla seedlings. Taken together, these findings provide beneficial information toward understanding the mechanism of CA and freezing stress in B. platyphylla. Furthermore, the substantial activity of physiological and biochemical results could be used as selection criteria for screening time and temperature points of cold/freezing stress in further omics analyses. In addition, the combination of current study results, further omics analyses, and genetic engineering techniques directly contribute to sustainable forest management systems, tree plantations, and conservation of tree species, especially non-cold/non-freezing tolerant tree species.

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