Selection for Differential Productivity Among Juvenile Maize Plants: Associated Net Photosynthetic Rate and Leaf Area Changes 1

Crop Science ◽  
1971 ◽  
Vol 11 (3) ◽  
pp. 334-339 ◽  
Author(s):  
W. D. Hanson
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yinli Bi ◽  
Huili Zhou

AbstractA well-developed canopy structure can increase the biomass accumulation and yield of crops. Peanut seeds were sown in a soil inoculated with an arbuscular mycorrhizal fungus (AMF) and uninoculated controls were also sown. Canopy structure was monitored using a 3-D laser scanner and photosynthetic characteristics with an LI-6400 XT photosynthesis system after 30, 45 and 70 days of growth to explore the effects of the AMF on growth, canopy structure and photosynthetic characteristics and yield. The AMF colonized the roots and AMF inoculation significantly increased the height, canopy width and total leaf area of the host plants and improved canopy structure. AMF reduced the tiller angle of the upper and middle canopy layers, increased that of the lower layer, reduced the leaf inclination of the upper, middle and lower layers, and increased the average leaf area and leaf area index after 45 days of growth, producing a well-developed and hierarchical canopy. Moreover, AMF inoculation increased the net photosynthetic rate in the upper, middle and lower layers. Plant height, canopy width, and total leaf area were positively correlated with net photosynthetic rate, and the inclination angle and tiller angle of the upper leaves were negatively correlated with net photosynthetic rate. Overall, the results demonstrate the effects of AMF inoculation on plant canopy structure and net photosynthetic rate.


1991 ◽  
Vol 9 (3) ◽  
pp. 163-167
Author(s):  
Stuart L. Warren ◽  
Frank A. Blazich ◽  
Mack Thetford

Abstract Uniconazole was applied as a foliar spray or medium drench to six woody landscape species: ‘Sunglow’ azalea; flame azalea; ‘Spectabilis’ forsythia; ‘Compacta’ holly; ‘Nellie R. Stevens’ holly; and mountain pieris. One hundred days after uniconazole application, leaf, stem, and top dry weight of all species, except flame azalea and mountain pieris, decreased as uniconazole concentration increased. Compared to controls, stem and leaf dry weight were reduced by uniconazole 18 to 60% and 13 to 32%, respectively, depending on species and method of application. Stem dry weight was reduced to a greater degree, compared to leaf dry weight. For all species, drench application was more effective than foliar spray in reducing leaf, stem, and top dry weight. Leaf area of ‘Spectabilis’ forsythia and ‘Nellie R. Stevens’ holly decreased with increasing rates. However, specific leaf weight was not affected. Uniconazole did not significantly affect leaf net photosynthetic rate, stomatal conductance or internal leaf CO2 concentrations in ‘Spectabilis’ forsythia or ‘Nellie R. Stevens’ holly. No phytotoxicity was observed on any species.


1985 ◽  
Vol 65 (4) ◽  
pp. 819-829 ◽  
Author(s):  
P. GIRARDIN ◽  
A. DELTOUR ◽  
M. TOLLENAAR

A prerequisite for an informed strategy regarding nitrogen application in maize (Zea mays L.) is a knowledge of the physiology of plant responses to nitrogen. This study consisted of two experiments on maize plants grown in pails. One experiment was conducted in controlled-environment growth rooms, the other was conducted in the field. N-deficient and control maize plants were evaluated for photosynthetic rate (P), chlorophyll content (CC), nitrogen content, and green leaf area; comparisons between these four parameters were made. During N starvation, rate of senescence (i.e. decrease in green leaf area) of the old leaves was higher in N-deprived plants than in control plants. P and CC of all leaves in the N-deficient treatment decreased during nitrogen withdrawal. After the deprivation period, when the plants were resupplied with N, senescence was delayed relative to control plants. The increase of CC in treatment plants was slower than the recovery of photosynthetic rate; in fact, CC was a poor indicator of photosynthetic activity. The delay in leaf senescence corresponded with regreening in leaves of N-deprived plants following N addition. This delay could be partly explained by an overcompensation in plant N requirement involving both a rapid increase in P, and a slower increase in CC. The effects of resupplying plants with nitrogen following a N-deprivation period lead us to believe that the observed leaf yellowing is actually a premature senescence which is reversible, and that a low N content is not the single causal factor of senescence.Key words: Chlorophyll content, leaf area, photosynthetic rate, Zea mays L.


1984 ◽  
Vol 14 (6) ◽  
pp. 924-932 ◽  
Author(s):  
Neil D. Nelson ◽  
Paul Ehlers

Light-saturated net photosynthetic rates per unit leaf area were 1.6–2.1 times greater for the photosynthetically mature leaves of plants of two hybrid Populus clones (NC-5260, 'Tristis No.1' (Populustristis Fisch. × P. balsamifera L.); NC-5326, 'eugenei' (P. deltoides Bartr. ex Marsh. × P. nigra L.)) grown in pots in the field than in comparable plants from a controlled environment growth room and a winter greenhouse. Stomatal resistances to CO2 in the field trees were only 0.4–0.6 of those in growth room and greenhouse trees. Mesophyll (residual) resistances to CO2 in field trees were 0.4–0.8 of those in growth room and greenhouse trees. Field plants had specific leaf weights 1.5–1.8 times higher than growth room and greenhouse plants, likely primarily owing to the greater average photosynthetic photon flux density in the field (835, 225, and 142 μE m−2 s−1 for field, growth room, and greenhouse conditions, respectively). When net photosynthetic rates (Ps) were corrected for the differences in specific leaf weights to derive net photosynthetic rate per unit leaf dry weight, the values were similar for plants from the three environments (Ps in field trees was 0.9–1.2 times Ps in growth room and greenhouse trees); gross photosynthetic rates per unit leaf weight were even more similar. Internal leaf CO2 concentrations, and photorespiration and dark respiration rates per unit leaf area were not related to growth environment. However, photorespiration rate as a percentage of net photosynthetic rate was lower in the field trees (12–16% in field trees, 19–24% in growth room trees, and 23–39% in greenhouse trees). Net photosynthetic rate was shown to be under strong genetic control in these clones. The effects of growth environment on variables of carbon exchange are sensitive to the basis of expression of those variables.


2016 ◽  
Vol 44 (2) ◽  
pp. 382-392 ◽  
Author(s):  
Juwei HU ◽  
Xin DAI ◽  
Guangyu SUN

Light quality can influence the photosynthetic characteristics, morphology and physiological processes of plants. To investigate the effects of different light qualities (white light, W; red light, R; blue light, B; mixture of red and blue light, RB) of light emitting diodes (LEDs) and white cold fluorescent lamp on the growth and morphology of fruiting mulberry plants (Morus alba L. cv. ‘Longsang No.1’), fruiting mulberry plants were grown under different light qualities: W, R, B and RB of the same photosynthetic photo flux density (PPFD; 100 μmol m-2 s-1) for 20 d. Our results showed that stem length and leaf area of plants grown under R were the highest. However, stem length and leaf area of plants grown under B were lowest. Dry weights (DW), leaf mass per area (LMA), chlorophyll a/b ratio, soluble protein content, sucrose and starch content, and total leaf nitrogen (N) content of plants grown under R were the lowest. Net photosynthetic rate (Pn), stomatal conductance (gs), and actual photochemical efficiency of PSII (ΦPSII) of plants grown under RB were similar to plants grown under W. Net photosynthetic rate (Pn) and ΦPSII of plants grown under R and B were lower than plants grown under W and RB. Antioxidant enzymes activity of plants grown under R, RB and B were higher than plants grown under W. The number of leaf stomata, leaf thickness, palisade tissue length and spongy tissue length were the lowest in plants grown under R. The number of leaf stomata, leaf thickness and palisade tissue length of plants grown under RB and B were higher than plants grown under R. The results of this study indicate that a certain ratio of mixed red and blue LEDs light can reduce adverse effects of monochromatic red and blue LEDs light on fruiting mulberry growth and development.


HortScience ◽  
2019 ◽  
Vol 54 (1) ◽  
pp. 167-174 ◽  
Author(s):  
Tongyin Li ◽  
Guihong Bi ◽  
Richard L. Harkess ◽  
Geoffrey C. Denny ◽  
Carolyn Scagel

Plant growth, water use, photosynthetic performance, and nitrogen (N) uptake of ‘Merritt’s Supreme’ hydrangea (Hydrangea macrophylla) were investigated. Plants were fertilized with one of five N rates (0, 5, 10, 15, or 20 mm from NH4NO3), irrigated once or twice per day with the same total daily amount of water, and grown in either a paper biodegradable container or a traditional plastic container. Greater N rate generally increased plant growth index (PGI) in both plastic and biocontainers. Leaf and total plant dry weight (DW) increased with increasing N rate from 0 to 20 mm and stem and root DW were greatest when fertilized with 15 mm and 20 mm N. Plants fertilized with 20 mm N had the greatest leaf area and chlorophyll content in terms of SPAD reading. Container type had no influence on DW accumulation or leaf area. N concentrations (%) in leaves, roots, and the entire plant increased with increasing N rate. N concentrations in roots and in the entire plant were lower in biocontainers compared with plastic containers. Greater N rate generally increased daily water use (DWU), and biocontainers had greater DWU than plastic containers. The 20 mm N rate resulted in the highest net photosynthetic rate measured on 11 Sept. and 22 Sept. (65 and 76 days after treatment). Net photosynthetic rate (measured on 8 Oct.) and stomatal conductance (gS) (measured on 27 Aug., 22 Sept., and 8 Oct.) were lower in biocontainers compared with plastic containers. Two irrigations per day resulted in higher substrate moisture at 5-cm depth than one irrigation per day, and slightly increased PGI on 19 Aug. However, irrigation frequency did not affect photosynthetic rate, gS, or N uptake of hydrangea plants except in stems. Considering the increased water use of hydrangea plants when grown in the paper biocontainer and lower plant photosynthesis and N uptake, the tested paper biocontainer may not serve as a satisfactory sustainable alternative to traditional plastic containers.


2009 ◽  
Vol 17 (3) ◽  
pp. 474-478
Author(s):  
Qun-Long LIU ◽  
Chan-Juan NING ◽  
Duo WANG ◽  
Guo-Liang WU ◽  
Hong-Mei ZHANG ◽  
...  

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