Chloroplasts are commonly the site of the earliest abiotic injury visible in plant ultrastructure. In this study, six inbred lines of maize (Zea mays L.) were used to analyze changes in the ultrastructure of chloroplasts and related physiological parameters under conditions of drought stress simulated by 20% polyethylene glycol 6000 (-0.6 MPa) for two days. Chloroplasts of three maize lines proved to be more sensitive. They showed changes in the ultrastructure in response to drought, including damage of thylakoid membranes, an increase in the number and size of plastoglobuli, swelling of thylakoid membranes both stromal and granal, disorganization of the thylakoid membrane system, an obvious increase in the intrathylakoid space, and a decrease in the
length-to-width ratio and area of chloroplasts. In addition, the contents of malondialdehyde increased markedly in the sensitive lines. Contrary to the sensitive lines, stable structures and shapes of chloroplasts were observed in the drought-resistant lines; it could be considered as an advantage contributing to drought tolerance in the plants. In addition, the drought index of leaf fresh mass (LMDI) in the drought-sensitive lines was ≤ 0.5, which was also associated with a lower content of leaf chlorophyll. In contrast, drought tolerance coincided with lesser growth reduction, and higher LMDI and leaf chlorophyll content., R. X. Shao, L. F. Xin, H. F. Zheng, L. L. Li, W. L. Ran, J. Mao, Q. H. Yang., and Obsahuje seznam literatury
Príspevok je pokusom stručne charakterizovat rozsiahly arzenál súčasných astronomických prístrojov a metód s krátkym presahom do blízkej budúcnosti. Podstatným znakom astronomického výskumu je multispektrálnosť s nasadením kozmických observatórií. Vel'ký pozemský optický teleskop už sám o sebe nestačí a k dosiahnutiu perfektného obrazu daného difrakčným limitom je nevyhnutná aktívna a adaptívna optika s následnou rekonštrukciou obrazu založenou na Fourierovej transformácii. Interpretačným nástrojom napomáhajúcim pochopiť a vysvetliť pozorovania sú počítačové numerické simulácie. Vybrané vzorky sú kompromisom poznačeným profesionálnym zameraním autora na fyziku Slnka v najlepšej snahe zachovať ich všeobecnejšiu platnosť., The review attempts to characterize briefly a vast arsenal of contemporary astronomical instruments and methods with an outlook to the near future. Essential features of astronomical research are multispectral observations involving both ground and space observatories. Big ground-based telescope in itself is no longer sufficient. Supporting active and adaptive optics with follow-up post-processing and image reconstruction based on Fourier transform are needed to achieve perfect diffraction-limited image. Numerical simulations are essential tools in interpretation and explanation of observations. Presented samples are influenced by the author's specialization in solar physics but he seeks to maintain their generic validity., Július Koza., and Obsahuje bibliografii