RELATIONSHIPS BETWEEN CARBON DIOXIDE EXCHANGE RATE, PHOTOSYNTHETIC AREA AND BIOMASS IN PEA

1986 ◽  
Vol 66 (3) ◽  
pp. 465-472 ◽  
Author(s):  
S. L. A. HOBBS
Keyword(s):  
Carbon Dioxide ◽  
Exchange Rate ◽  
Pisum Sativum ◽  
Chlorophyll Content ◽  
Substantial Reduction ◽  
Dry Weight ◽  
Stomatal Resistance ◽  
Carbon Dioxide Exchange ◽  
Shoot Dry Weight ◽  
Pisum Sativum L

Compensation between carbon dioxide exchange rate per unit photosynthetic area (CER) and total photosynthetic area (TPA) of a plant was examined in field-grown pea (Pisum sativum L.). Eight near-isogenic lines of cv. Alaska, representing all possible phenotypes of the genes af (leaflets transformed to tendrils), st (reduced stipule area) and tl (tendrils transformed to leaflets), were examined. The CER was measured on the leaflets (AfAf), tendrils (afafTlTl) or minute leaflets (afaftltl). The TPA was significantly reduced by the st gene in AfAf types (normal leaflets) with an apparently associated increase in CER. The st gene also significantly reduced the TPA in afaf types but there was no associated increase in CER. Tendrils had a lower CER than normal leaflets and comprised 22% of the TPA of the semi-leafless (afafStStTlTl) type. Crosses were made between a semi-leafless pea and four normal-leafed types previously selected for high or low CER. The CER means (normal leaflets) of the F1 progeny showed variability which was related to parental values. This was also true for the CER means (tendrils) of the populations of semi-leafless F2 segregants showing that genetic variability for CER can exist in tendrils. In the F2, tendril CER was correlated negatively to stomatal resistance and positively to chlorophyll content and final shoot dry weight (biomass). Genetic improvement in CER may be important when a plant ideotype requires substantial reduction in TPA.Key words: Photosynthesis, pea, chlorophyll content, stomatal resistance, Pisum sativum

COMPARISON OF PHOTOSYNTHESIS IN NORMAL AND TRIAZINE-RESISTANT Brassica

1987 ◽  
Vol 67 (2) ◽  
pp. 457-466 ◽  
Author(s):  
S. L. A. HOBBS
Keyword(s):  
Carbon Dioxide ◽  
Exchange Rate ◽  
Chlorophyll A ◽  
Dry Weight ◽  
Stomatal Resistance ◽  
Carbon Dioxide Exchange ◽  
Shoot Dry Weight ◽  
Significant Difference ◽  
The Difference ◽  
Net Assimilation

In spaced field plantings, triazine-resistant types of Brassica campestris L. and B. napus L. had a carbon dioxide exchange rate (CER) 28% lower in 1983 and 25% lower in 1984 than normal (triazine-susceptible) types. In plots simulating agronomic spacings in 1984, the difference between CER in normal and resistant types was 17% for B. campestris, 14% for B. napus and 13% for B. juncea L. Differences were apparent throughout the season and were not associated with any particular stage of growth. Resistant progeny from reciprocal crosses between resistant and susceptible plants of B. napus exhibited reduced CER at all levels of photosynthetically active radiation and at all temperatures. There was no significant difference between plant types for chlorophyll a + b content or chlorophyll a/b ratio. Shoot dry weight, stomatal resistance and specific leaf weight were higher in the normal types, but there was no difference between types in either relative growth rate or net assimilation rate. The reduced biomass was not therefore linked to reduced CER.Key words: Carbon dioxide exchange rate, herbicide, oilseed, rapeseed

The photosynthetic capacity of stubble leaves and their contribution to growth of the lucerne plant after low level cutting

1972 ◽  
Vol 23 (2) ◽  
pp. 225 ◽  
Author(s):  
KC Hodgkinson ◽  
NG Smith ◽  
GE Miles
Keyword(s):  
Carbon Dioxide ◽  
Exchange Rate ◽  
Photosynthetic Capacity ◽  
Dry Weight ◽  
Carbon Dioxide Exchange ◽  
Weight Changes ◽  
Plant Parts ◽  
Tap Root ◽  
Leaf Resistance ◽  
Mesophyll Resistance

The net carbon dioxide exchange rate (NCE) of lucerne (Medicago sativa cv. Hunter River) stubble leaves was found to be low (c. 55 ng CO2 cm-2 sec-1) immediately after removing shoots 15 cm above the stem base. However, within several days the NCE rose to a maximum of 130 ng CO2 cm-2 sec-1 on day 8. This peak rate was similar to that of recently expanded new leaves and held for about 3 days before declining. Leaves of similar age and position on uncut plants showed a steady decline in NCE. Leaf resistance, r'l, was low (c. 0.8 sec cm-1) and did not change as the NCE increased during the first 8 days. Mesophyll resistance, r'm, to carbon dioxide diffusion was initially high and declined from c. 9 to 2 sec cm-1 during this period. Comparison of dry weight changes of plant parts after stubble leaves were either retained or removed suggested that the tap-root benefited most by stubble leaf retention. The contribution to new shoots from stubble leaves appeared to be slight. However, when stubble leaves were exposed to 14CO2 on day 11, photosynthate was mainly exported into the shoot arising from the axil of the exposed leaf. This suggests that stubble leaves substitute, in part or completely, for the supply of carbohydrate to stubble shoots normally derived from reserves mobilized in the tap-root. The likely causes of rejuvenation in NCE of stubble leaves after partial shoot removal are discussed along with the significance of this photosynthetic contribution to regrowth of the lucerne plant.

Characteristics of the canopy, root system and grain yield of a crop of Lupinus angustifolius cv. Unicrop

1975 ◽  
Vol 26 (3) ◽  
pp. 497 ◽  
Author(s):  
EAN Greenwood ◽  
P Farrington ◽  
JD Beresford
Keyword(s):  
Carbon Dioxide ◽  
Grain Yield ◽  
Leaf Area ◽  
Time Course ◽  
Dry Weight ◽  
Grain Filling ◽  
Main Axis ◽  
Carbon Dioxide Exchange ◽  
Area Index ◽  
Plant Parts

The time course of development of a lupin crop was studied at Bakers Hill, Western Australia. The aim was to gain insight into the crop factors influencing yield. Weekly measurements were made of numbers and weights of plant parts, and profiles of roots, leaf area and light interception. A profile of carbon dioxide in the crop atmosphere was taken at the time of maximum leaf area, and the net carbon dioxide exchange (NCE) of pods was estimated for three successive weeks. The crop took 10 weeks to attain a leaf area index (LAI) of 1 and a further 9 weeks to reach a maximum LAI of 3.75, at which time only 33% of daylight reached the pods on the main axis. Once the maximum LAI was attained at week 19, leaf fall accelerated and rapid grain filling commenced almost simultaneously on all of the three orders of axes which had formed pods. Measurements of NCE between pods on the main axis and the air suggest that the assimilation of external carbon dioxide by the pods contributed little to grain filling. Grain dry weight was 2100 kg ha-1 of which 30%, 60% and 10% came from the main axis, first and second order apical axes respectively. Only 23% of the flowers set pods and this constitutes an important physiological limitation to grain yield.

scholarly journals Whole-plant Response of Six Poinsettia Cultivars to Three Fertilizer and Two Irrigation Regimes

1996 ◽  
Vol 121 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Ursula Schuch ◽  
Richard A. Redak ◽  
James Bethke
Keyword(s):  
Leaf Area ◽  
Chlorophyll Content ◽  
Dry Weight ◽  
Shoot Biomass ◽  
Vegetative Development ◽  
Chlorophyll Contents ◽  
Shoot Dry Weight ◽  
Irrigation Regimes ◽  
Whole Plant ◽  
Leaf N

Six cultivars of poinsettia (Euphorbia pulcherrima Wind.), `Angelika White', `Celebrate 2', `Freedom Red', `Lilo Red', `Red Sails', and `Supjibi Red' were grown for 9 weeks during vegetative development under three constant-feed fertilizer treatments, 80,160, or 240 mg N/liter and two irrigation regimes, well-watered (high irrigation) or water deficient (low irrigation). Plants fertilized with 80 or 240 mg N/liter were 10% to 18% shorter, while those fertilized with 160 mg N/liter were 25 % shorter with low versus high irrigation. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations. Low irrigation reduced leaf area, leaf, stem, and shoot dry weight 3670 to 41%. Cultivars responded similarly to irrigation and fertilizer treatments in all components of shoot biomass production and no interactions between the main effects and cultivars occurred. Stomatal conductance and transpiration decreased with increasing fertilizer rates or sometimes with low irrigation. Highest chlorophyll contents occurred in leaves of `Lilo Red' and `Freedom Red'. Leaves of plants fertilized with 80 mg N/liter were deficient in leaf N and had 40 % to 49 % lower leaf chlorophyll content compared to plants fertilized with 160 or 240 mg N/liter. Irrigation had no effect on leaf N or chlorophyll content. At the end of the experiment leaves of `Supjibi Red' and `Angelika White' contained higher concentrations of soluble proteins than the other four cultivars.

Effect of weed management on weeds, and on the nodulation, nitrogenase activity, growth and yield of pea (Pisum sativum)

2006 ◽  
Vol 54 (4) ◽  
pp. 469-485 ◽  
Author(s):  
G. Singh ◽  
D. Wright
Keyword(s):  
Pisum Sativum ◽  
Nitrogen Content ◽  
Weed Management ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Strong Relationship ◽  
Dry Weight ◽  
Growth And Yield ◽  
N Content ◽  
Shoot Dry Weight

Effects of one pre-emergence herbicide (terbutryn/terbuthylazine) and one post-emergence herbicide (bentazone) along with unweeded and hand-weeded controls on weeds and on the nodulation, nitrogenase activity, nitrogen content, growth and yield of pea (Pisum sativum) were studied. Terbutryn/terbuthylazine was applied pre-emergence @ 1.40, 2.80 and 5.60 kg/hawhereas bentazone was sprayed 6 weeks after sowing @ 1.44, 2.88 and 5.76 kg/h. Terbutryn/terbuthylazine controlled all the weeds very effectively, whereas bentazone did not control some weeds such as Polygonum aviculare, Poa annua and Elymus repens. The herbicides decreased the number of nodules, the dry weight of nodules, the nitrogenase activity, the shoot dry weight, the nitrogen content in the straw and seeds, and the seed yield of peas, the effects generally being higher at higher rates of application. The adverse effects of herbicides on these parameters might be due to their effects on plant growth, as both the herbicides are known to adversely affect photosynthesis. Nitrogenase activity did not correlate well with plant-N content or shoot dry weight. However, there was a strong relationship between plant biomass and plant-N content, which suggests that researchers can rely on these parameters for studying the effects of treatments on nitrogen fixation, rather than measuring nitrogenase activity.

Herbicidal Effects on Crownvetch Rhizobia and Nodule Activity

Weed Science ◽  
1986 ◽  
Vol 34 (3) ◽  
pp. 338-343 ◽  
Author(s):  
John Cardina ◽  
Nathan L. Hartwig ◽  
Felix L. Lukezic
Keyword(s):  
Carbon Dioxide ◽  
Exchange Rate ◽  
Bacterial Growth ◽  
Indirect Effects ◽  
Carbon Dioxide Exchange ◽  
N Fixation ◽  
Intact Plants ◽  
Coronilla Varia ◽  
Direct Toxicity

Two strains of crownvetch (Coronilla variaL. # CZRVA) rhizobia were cultured in vitro with various rates of atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and bifenox [methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate]. Growth, measured turbidimetrically over 48 h, was similar for both strains. Atrazine and bifenox significantly reduced bacterial growth after 14 and 36 h, respectively, only at the highest concentrations tested (463 μM atrazine and 292 μM bifenox). Since growth of crownvetch rhizobia was apparently not affected by rates of atrazine or bifenox above reasonable soil solution concentrations, it is likely that herbicidal effects on nodulation were due to toxicity to the host plant rather than toxicity to these bacteria. In a growth chamber experiment, total nodule activity (TNA) and carbon dioxide exchange rate (CER) were measured simultaneously in an effort to distinguish direct atrazine effects on nodule function from indirect effects due to inhibition of photosynthesis and a resulting decrease in photosynthate supply to nodules. When 5 and 50 mg atrazine per kg soil were applied to intact plants, CER was severely reduced within 24 h, but similar reductions in TNA were not observed until 48 h after treatment. Total nodule activity was reduced similarly by atrazine and defoliation; the application of atrazine to defoliated plants did not inhibit TNA more than did defoliation alone. The data indicate that reductions in crownvetch nodule activity by atrazine are due to inhibition of photosynthesis or other processes rather than direct toxicity to N fixation.

Evaluation of the Superabsorbent Effect on the Yield and Some Growth Factors of Pisum sativum L. under Drought Stress Conditions

2019 ◽  
Vol 10 (2) ◽  
pp. 106-114
Author(s):  
Farahnaz A. Norodinvand ◽  
Davoud K. Dehkordi ◽  
Aslan Egdernezhad
Keyword(s):  
Growth Factors ◽  
Drought Stress ◽  
Pisum Sativum ◽  
Treatment Plan ◽  
Dry Weight ◽  
Stress Conditions ◽  
Control Treatment ◽  
Significant Information ◽  
Superabsorbent Hydrogel ◽  
Pisum Sativum L

Background: Deficit irrigation is an optimum technique for producing products under drought stress conditions. The superabsorbent hydrogel is a hydrophilic polymer with cross-linked 3-D hydrophilic nets that are able to take up and keep noteworthy values of water and aquatic liquids. Recently published patents have provided significant information about the superabsorbent application in agriculture. Objective: The aim of this study was to investigate the superabsorbent effect on the yield and some of the growth factors of Pisum sativum L. under drought stress conditions. Methods: The experimental factors included: irrigation treatments at two levels of 100% and 75% water requirement by the plant. The second factor included the levels of superabsorbent application which included three levels of control treatment, potting soil with a weight percentage of 0.5 and 1. The third factor was the location of the superabsorbent application. Results: According to the results, the largest root length value corresponded to I2S1U treatment plan, the largest root dry weight value corresponded to I1S2U treatment plan, the largest plant dry weight corresponded to I2S1U treatment plan, the largest grain dry weight corresponded to I2S1U treatment plan, the largest number of grains per pod corresponded to I2S2U treatment plan and the largest number of pods per plant corresponded to I2S1U treatment plan which were significant at 5% level. Conclusion: It was concluded that the presence of the superabsorbent at the lower end of the pot was effective in providing water and nutrients for the plant root.

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