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2. Leaf senescence patterns and photosynthesis in four leaf flushes of two deciduous oak (Quercus) species
- Creator:
- Tobiáš, D.J., Ikemoto, A., and Nishimura, T.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- chlorophyll, leaf area, leaf duration, leaf number, net photosynthetic rate, Quercus acutissima, and Quercus serrata
- Language:
- Multiple languages
- Description:
- Changes in chlorophyll (Chl) a+b and a/b, senescence patterns during Chl loss and changes in net photosynthetic rate (P^) of four leaf flushes in Quercus acutissima and Q. serrata were studied. Emergent current-year leaves were classified according to the order of shoot growth flushes (first to fourth flush groups). Senescence patterns showed that leaf fall started from the leaf cohorts of the first flush group (the "oldest" leaf cohorts) which cuhninated upwards to the fourth leaf flush group (the "yoímgest" leaf cohorts). Senescence during Chl loss was accompanied by a decline in Pf^. A strong influence by the leaf flushing phenomenon on senescence was found which limited leaf bearing period and duration of Having large total leaf area and moderately long duration, tiie third and second leaf flush groups reflected the highest photosynthetic potential. This may be a positive attribute since the duration by which these plants maximize the use of its assimilatory organs is an important factor for their carbon fixation.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Responses of runner bean plants to excess copper as a function of plant growth stages: effects on morphology and structure of primary leaves and their chloroplast ultrastructure
- Creator:
- Maksymiec, W., Bednara, J., and Baszyński, T.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- chlorophyll, CUSO4, digalactosyl diacylglycerol, leaf area, leaf density, monogalactosyl diacylglycerol, Phaseolus coccineus L., senescence, and stroma lamellae
- Language:
- Multiple languages
- Description:
- Morphological and ultrastructural changes, the chlorophyll (Chl) content and Chl a fluorescence induction were studied in primary leaves of runner beán plants (Phaseolus coccineus L. cv. Pi?kny Jaš) grown in Knop solution and treated with excess Cu [20 g(CuS04 x 5 H2O) m"^] at difíerent growth stages. The plants were exposed to the metal for 12 d. Cu added to the nutrient solution at the beginning growth stage induced significant leaf area reduction (31 %) as well as increase of Chl accumulation (148 %) and leaf density (122 %). No ultrastructural changes of chloroplasts were seen. Application of Cu at the advanced growth stage caused relatively smáli changes except local disturbances in stroma lamellae and leaf reduction to 70 % of control. Significant disorganization of chloroplast ultrastructure, smáli leaf area reduction (80 %) but specific leaf area increase (163 %) and leaf density decrease (67 %) were seen only in the primary leaves of plants treated with Cu at the finál stage of growth. These changes, similar to senescence response, were accompanied by Fy/Fo ratio decrease to 67 % in comparison with control.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public