Quantifying.Associations among Dimensions of Ears and Their Form Factors in Maize(Zea Mays)Using Dimensional Analysis

Ear morphological traits such as volume and shape are important features of maize and the quantitative associations among them can help understand kernel yield determination. 150 mature ears each of 4 maize cultivars were collected from field experiments, and ear length(L), diameter(D), area(S) and volume(V) were recorded for individual ears, kernel weight per ear also recorded for a portion of the examined ears. Following principles of dimensional analysis, 8 theoretical equations of 3 sets,which relate ear higher dimensions to its length and diameter, were developed and parameterized and validated with the field observations. The 3 optimized equations showed that the shape of ears in maize can be featured with 3 dimensionless form factors, namely diameter-to-length ratio(c=D/L), areal form factor(b=S/L/D), and volumetric form factor(a=V/L/D/D). Statistically,all of them were significantly different among cultivars, and a's values varied from 0.582 to 0.612, and b's 0.839-0.868, and c's 0.242-0.308. Volumetric form factor and areal form factor could estimate precisely ear volume and area respectively, but diameter-to-length ratio was not suitable to estimate ear diameter by its length. Ear volume explained almost all variation of ear kernel weight and product L*D*D did the same substantially. Dimensional analysis proved to be promising in understanding relationship among morphological traits of ears in maize. Its application in crop researches should improve our knowledge of the physical properties of crop plants.

Aequorin-Based Luminescence Imaging Reveals Stimulus-and Tissue-Specific Ca^2＋ Dynamics in Arabidonsis Plants

Calcium ion is a versatile second messenger for diverse cell signaling in response to developmental and environmental cues. The specificity of Ca^2＋-mediated signaling is defined by stimulus-elicited Ca^2＋ signature and down-stream decoding processes. Here, an Aequorin-based luminescence recording system was developed for monitoring Ca^2＋ in response to various stimuli in Arabidopsis. With the simple, highly sensitive, and robust Ca^2＋ recording, this system revealed stimulus-and tissue-specific Ca^2＋ signatures in seedlings. Cellular Ca^2＋ dynamics and relationship to Aequorin-based Ca^2＋ recording were explored using a GFP-based Ca^2＋ indicator, which suggested that a synchronous cellular Ca^2＋ signal is responsible for cold-induced Ca^2＋ response in seedlings, whereas asynchronous Ca^2＋ oscillation contributes to osmotic stress-induced Ca^2＋ increase in seedlings. The optimized recording system would be a powerful tool for the iden-tification and characterization of novel components in Ca^2＋ -mediated stress-signaling pathways,