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Effect of drought stress on photosynthesis, partitioning of photo- assimilates and grain yield in rapeseed cultivars
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Abstract: (5502 Views) |
| Effect of drought stress at flowering stage on the rate of photosynthesis, partitioning of photoassimilates and its relation with grain yield of 14 rapeseed cultivar was studied in agricultural research field, University of Tehran, Karaj, Iran, in 2007-2008 crooping season. A split plot c arrangement in randomized block design with 3 replications was used. Main plots included two regimes of irrigation (full irrigation and drought stress at flowering stage) and sub plots consisted 14 cultivars of rapeseed. Drought stress was imposed at flowering stage by stopping irrigation and were rewatered when soil water potential reached -1.5 Mpa. Results showed that under full irrigation conditions photosynthesis rate, transpiration and PWUE declined. Similar changes in photosynthesis rate, transpiration rate and Ci concentration were observed due to water stress implying the role of stomatal limitation to photosynthesis under stress conditions. Chlorophyll index increased under mild stress condition, however, as stress intensified, chlorophyll index significantly reduced. Cultivars showed significant differences for photosynthesis rate under water stress and non stress conditions, however, grain yield of cultivars were affected differently by water stress. Significant correlation coefficientswere not observed between photosynthesis rates and grain yield under different moisture regimes. Moreover, drought stress at flowering stage affected partitioning of photoassimilates between different plant organs. Drought stress at flowering stage decreased grain yield by 51% and harvest index through increasing dry weight of leaf, stem, root, and decreasing dry weight of silique or partitioning of assimilates to vegetative organs than reproductive organs. The P.F cultivar with grain yield of 3597 kg.ha-1 in full irrigation conditions and Okapi with grain yield of 1595 kg.ha-1 and greater harvest index had higher agronomic performance and grain yield. |
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| Keywords: Partitioning, Photoassimilates, Drought stress, Photosynthesis, Chlorophyll index and Rapeseed. |
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Full-Text [PDF 873 kb]
(4420 Downloads)
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Type of Study: Scientific & Research |
Subject:
Special
Received: 2015/02/17 | Accepted: 2015/02/17 | Published: 2015/02/17
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