Subcellular compartmentation of glutathione in dicotyledonous plants

This study describes the subcellular distribution of glutathione in roots and leaves of different plant species (Arabidopsis, Cucurbita, and Nicotiana). Glutathione is an important antioxidant and redox buffer which is involved in many metabolic processes including plant defense. Thus information on the subcellular distribution in these model plants especially during stress situations provides a deeper insight into compartment specific defense reactions and reflects the occurrence of compartment specific oxidative stress. With immunogold cytochemistry and computer-supported transmission electron microscopy glutathione could be localized in highest contents in mitochondria, followed by nuclei, peroxisomes, the cytosol, and plastids. Within chloroplasts and mitochondria, glutathione was restricted to the stroma and matrix, respectively, and did not occur in the lumen of cristae and thylakoids. Glutathione was also found at the membrane and in the lumen of the endoplasmic reticulum. It was also associated with the trans and cis side of dictyosomes. None or only very little glutathione was detected in vacuoles and the apoplast of mesophyll and root cells. Additionally, glutathione was found in all cell compartments of phloem vessels, vascular parenchyma cells (including vacuoles) but was absent in xylem vessels. The specificity of this method was supported by the reduction of glutathione labeling in all cell compartments (up to 98%) of the glutathione-deficient Arabidopsis thaliana rml1 mutant. Additionally, we found a similar distribution of glutathione in samples after conventional fixation and rapid microwave-supported fixation. Thus, indicating that a redistribution of glutathione does not occur during sample preparation. Summing up, this study gives a detailed insight into the subcellular distribution of glutathione in plants and presents solid evidence for the accuracy and specificity of the applied method

Cotton relay intercropping under continuous cotton-wheat cropping system

Cotton-wheat is an important cropping system of the world in which cotton is sown after harvest of wheat in the start of summer season. In the recent decades, Bt cotton cultivars have been introduced to better combat the bollworms. However, the Bt cotton cultivars have a growth period longer than the conventional cotton cultivars. This situation pressured the farmers to opt to grow either wheat or cotton in a single year. This not only could result in economic loss to farmers but also could threaten the food security of the cropping region. Relay cropping of cotton in wheat was suggested by an innovative solution for maintaining the productivity and sustainability of cotton-wheat cropping system. Relay cropping of cotton in wheat could be done either by inter-seeding the seeds of cotton in free space between the wheat strips (while wheat is at reproductive phase) or by transplanting the 5–7-week-old cotton seedlings between the wheat strips. Subsequent research work indicated that relay cropping could improve the resource use efficiency and overall productivity of the cotton-wheat cropping system. In a 2-year study in Punjab, Pakistan, conducted at two locations, intercropping cotton in bed−/ridge-sown wheat in early March improved the overall system productivity and cotton fiber quality as compared with conventionally tilled cotton sown after harvest of flat-sown wheat in late April. Future research may investigate the weed control and incorporation of conservation agricultural practices in the cotton-wheat relay intercropping systems