Haberlea rhodopensisis a resurrection plant with an extremely high desiccation tolerance. Even after long periods of almost full desiccation, its physiological functions are recovered shortly upon re-watering. In order to identify physiological strategies which contribute to its remarkable drought stress tolerance we used near infrared spectroscopy to investigate the state of water in the leaves of this plant and compared it to its relative, non-resurrection plant speciesDeinostigma eberhardtii. Here we show, using a novel aquaphotomics spectral analysis, thatH.rhodopensisperforms a dynamic regulation of water molecular structure during dehydration directed at drastic decrease of free water molecules, increase of water molecules with 4 hydrogen bonds, and a massive accumulation of water dimers in the full desiccation stage. Our findings suggest that changes in water structure mirror the changes in major metabolites and antioxidants which together constitute a robust defense system underlying the desiccation tolerance of the resurrection plant, while the water dimer may hold special importance for the “drying without dying” ability.
1 September 2004 in Postharvest Biology and Technology
A short wavelength near infrared (NIR) analysis method for somatic cell count (SCC) determination in unhomogenised raw milk was developed. NIR spectra (700–1100nm) of unhomogenised milk samples from 14 cows during days 7 to 36 of their lactation were measured for two consecutive years. Measurements from animals with different physiological conditions (healthy and mastitic)were included. A “leave-one-cow-out” cross-validation partial least square (PLS) regression model for SCC in the raw milk was developed. Good correlation ( R2=0.76) was observed between estimated and reference SCC levels in milk samples when the differential spectra and SCC reference values were used for developing the PLS model. The NIR estimation achieved a standard error of 0.3 LogSCC. The results were well within the range needed for real-time monitoring of milk on a daily basis. Thus, the NIR method may prove to be a valuable tool for monitoring somatic cells in routine milk samples analysed for dairy cow health management.
The development of non-destructive methods for early detection of cold stress of plants and the identification of cold-tolerant cultivars is highly needed in crop breeding programs. Current methods are either destructive, time-consuming or imprecise. In this study, soybean leaves’ spectra were acquired in the near infrared (NIR) range (588–1025 nm) from five cultivars genetically engineered to have different levels of cold stress tolerance. The spectra were acquired at the optimal growing temperature 27 °C and when the temperature was decreased to 22 °C. In this paper, we report the results of the aquaphotomics analysis performed with the objective of understanding the role of the water molecular system in the early cold stress response of all cultivars. The raw spectra and the results of Principal Component Analysis, Soft Independent Modeling of Class Analogies and aquagrams showed consistent evidence of huge differences in the NIR spectral profiles of all cultivars under normal and mild cold stress conditions. The SIMCA discrimination between the plants before and after stress was achieved with 100% accuracy. The interpretation of spectral patterns before and after cold stress revealed major changes in the water molecular structure of the soybean leaves, altered carbohydrate and oxidative metabolism. Specific water molecular structures in the leaves of soybean cultivars were found to be highly sensitive to the temperature, showing their crucial role in the cold stress response. The results also indicated the existence of differences in the cold stress response of different cultivars, which will be a topic of further research.