Evaluation of certain rainfed food and oil seed crops for their response to elevated CO₂ at vegetative stage

Abstract

Under the present global scenario of CO 2 increase (IPCC 1996), it has become pertinent for researchers all over the world to find solutions for future. Firstly, research can help to identify the crops which respond to the above situation and those which do not. Secondly, among the crops which respond, those with relatively a higher magnitude are to be identified initially to address the food and feed self-sufficiency followed by the soil improvement.Various reviews on the response of different crops revealed that an increase in CO 2 has a positive effect on the plant biomass. Kimball (1986) obtained an average increase of 21% in biomass in response to elevated CO 2 when he analyzed 94 observations of different plants. Cure (1985) and Cure and Acock (1986) reported that sorghum showed a stimulation of 5% increase in biomass with elevated CO 2 levels (scaled to 550 µmol/mol). Venkteshwara Rao (1999) observed that in groundnut cv. TMV-2 biomass production was 29% higher in elevated CO 2 (660 ppm) than in ambient CO 2 . In sunflower the growth was affected at elevated CO 2 by increasing net CO 2 assimilation rate (Tezara et al. 2002). It was observed that with elevated levels of CO 2 (using the FACE technology) there was a greater stimulation of belowground than aboveground biomass (Kimball et al. 2002). Under ample water and nutrients the root growth of C 3 grasses was stimulated by about 47% as compared with the 12% of shoots whereas in clover (C 3 legume) the root growth stimulation (25%) was nearly same as that of shoots (24%).In this paper an attempt was made to present the response of certain rainfed crops up to vegetative stage to enhanced levels of CO 2 and were compared with chamber control at ambient level CO 2 , which actually takes care of the deviation in temperature and relative humidity due to the OTC. The crops were raised directly in the field to avoid the root restriction in pots. In enhanced CO 2 condition, the CO 2 levels were elevated to set ppm continuously 24 h from the day of sowing to final sampling. The response reported that the actual effect of CO 2 with all other conditions maintained similar for both the treatments. MATERIAL AND METHODSThe seeds of sorghum (Sorghum bicolor L . The results showed significant differences between crops, conditions and time intervals, as well as the single and double order interactions for all the characters studied viz., total dry weight, stem dry weight, root dry weight, leaf dry weight, shoot length, root length and leaf area. Total dry weight and its components viz., stem dry weight, root dry weight and leaf dry weight along with leaf area showed a significant increase under enhanced CO 2 conditions. Among the four crops studied the overall results showed the highest response to elevated CO 2 by blackgram while the lowest response by sorghum.

Intra- specific variation in response of Jatropha (Jatropha curcas L.) to elevated CO2 conditions

“…In the present study, IC565044, which recorded in high percentage increase in root length (18 %), root volume (88 %), leaf dry weight (126 %) and root dry weight (74 %), and accession IC541651, which registered high increase for plant traits like plant height (50 %), root volume (88 %) and root dry weight (67 %) and IC544685 which enlisted high percentage increase in traits like plant height (58 %),girth (31 %), leaf area (100 %), shoot dry weight (206 %) and total biomass (125 %) may be appropriate for changed climatic conditions with high levels of CO 2 . Similar results in increase in total dry weight, stem, root and leaf dry weight; root and shoot length, leaf area and root: shoot ratio were reported by Vanaja et al (2006) in four crops belonging to three crop groups viz., cereals, pulses and oilseeds. They found maximum increase of total dry weight (79.7 %), stem dry weight (100.95 %), root dry weight (78.18 %) and leaf dry weight (71.18 %), shoot length (7.37 %) and leaf area (52.54 %) in black gram followed by sunflower, groundnut and sorghum.…”

Initial growth responses of blackgram (Vigna mungo L. Hepper) under elevated CO₂and moisture stress

“…Greengram grown under CO 2 enrichment was taller and attained a greater leaf area along with dry matter than ambient CO 2 grown plants at initial growth stages (Srivastava et al 2001). Under elevated CO 2 (600 ppm) and well-watered conditions the response of blackgram was higher than sorghum and sunflower at initial growth stages (Vanaja et al 2006)…”

Cultivar Specific Response of CO2 Fertilization on Two Tropical Mung Bean (Vigna radiata L.) Cultivars: ROS Generation, Antioxidant Status, Physiology, Growth, Yield and Seed Quality

“…Vanaja et al. () reported enhancement in phenotypical parameters (total dry weight, stem dry weight, root dry weight, leaf dry weight, shoot length, root length and leaf area) at 600 ppm CO 2 in two important rain‐fed food crops, viz. sorghum ( Sorghum bicolor L.…”