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2. Excess irradiance causes early symptoms of senescence during leaf expansion in photoautotrophically in vitro grown tobacco plants
- Creator:
- Radochová, B. and Tichá, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll a fluorescence, leaf area, leaf dry mass, leaf ontogeny, net oxygen evolution rate, Nicotiana, and photosynthesis
- Language:
- Multiple languages
- Description:
- Photosynthetic parameters, growth, and pigment contents were determined during expansion of the fourth leaf of in vitro photoautotrophically cultured Nicotiana tabacum L. plants at three irradiances [photosynthetically active radiation (400-700 nm): low, LI 60 µmol m-2 s-1; middle, MI 180 µmol m-2 s-1; and high, HI 270 µmol m-2 s-1]. During leaf expansion, several symptoms usually accompanying leaf senescence appeared very early in HI and then in MI plants. Symptoms of senescence in developing leaves were: decreasing chlorophyll (Chl) a+b content and Chl a/b ratio, decreasing both maximum (FV/FM) and actual (ΦPS2) photochemical efficiency of photosystem 2, and increasing non-photochemical quenching. Nevertheless, net photosynthetic oxygen evolution rate (PN) did not decrease consistently with decrease in Chl content, but exhibited a typical ontogenetic course with gradual increase. PN reached its maximum before full leaf expansion and then tended to decline. Thus excess irradiance during in vitro cultivation did not cause early start of leaf senescence, but impaired photosynthetic performance and Chl content in leaves and changed their typical ontogenetic course. and B. Radochová, I. Tichá.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Photosynthesis parameters in two cultivars of mulberry differing in salt tolerance
- Creator:
- Giridara Kumar, S., Lakshmi, A., Madhusudhan, K. V., Ramanjulu, S., and Sudhakar, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophylls, intercellular CO2 concentration, leaf area, leaf dry mass, Morus alba, net photosynthetic rate, salt stress, stomatal conductance, transpiration, and water use efficiency
- Language:
- Multiple languages
- Description:
- Three-month-old mulberry (Morus alba L.) cultivars (salt tolerant cv. S1 and salt sensitive cv. ATP) were subjected to different concentrations of NaCl for 12 d. Leaf area, dry mass accumulation, total chlorophyll (Chl) content, net CO2 assimilation rate (PN), stomatal conductance (gs), and transpiration rate (E) declined, and intercellular CO2 concentration (Ci) increased. The changes in these parameters were dependent on stress severity and duration, and differed between the two cultivars. The tolerant cultivar showed a lesser reduction in PN and gs coupled with a better Ci and water use efficiency (WUE) than the sensitive cultivar. and S. Giridara Kumar ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Photosynthetic characteristics in mulberry during water stress and rewatering
- Creator:
- Ramanjulu, S., Sreenivasalu, N., Giridhara Kumar, S., and Sudhakar, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- intercellular CO2 concentration, leaf area, leaf dry mass, Morus alba, net photosynthetic rate, photosystem 2, relative water content, stomatal conductance, transpiration rate, and water relations
- Language:
- Multiple languages
- Description:
- Three-month-old plants of mulberry (Morus alba L. cv. Kanva-2) were subjected to a drought stress by withholding water supply. As the leaf water potential (ΨW) was dropping progressively with the severity of treatment and increasing stress duration, the values of leaf area, dry mass accumulation, total chlorophyll (Chl) content, net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) were declined. The photosystem 2 (PS2) photochemical efficiency significantly decreased only at a severe stress treatment. The intercellular CO2 concentration (Ci) remained unaltered during a mild stress, yet it increased under moderate and severe stresses. The Ci/gs ratio reflected the mesophyll efficiency during water stress. Rewatering of the plants led to an almost complete recovery of PN, E, and gs, indicating that a short-term stress brings about reversible effects only. and S. Ramanjulu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Variations in photosynthetic rate and associated parameters with age of oil palm leaves under irrigation
- Creator:
- Suresh, K. and Nagamani, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- area leaf mass, chlorophyll, Elaeis, leaf area, leaf dry mass, stomatal conductance, and transpiration rate
- Language:
- Multiple languages
- Description:
- Net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) in an adult oil palm (Elaeis guineensis) canopy were highest in the 9th leaf and progressively declined with leaf age. Larger leaf area (LA) and leaf dry mass (LDM) were recorded in middle leaves. PN showed a significant positive correlation with gs and a negative relationship with leaf mass per area (ALM). The oil palm leaf remains photosynthetically active for a longer time in the canopy which contributes significantly to larger dry matter production in general and greater fresh fruit bunch yields in particular. and K. Suresh, C. Nagamani.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public