Four temperature treatments were studied in the climate controlled growth chambers of the Georgia Envirotron: 25/20, 30/25, 35/30, and 40/35 °C during 14/10 h light/dark cycle. For the first growth stage (V3-5), the highest net photosynthetic rate (PN) of sweet corn was found for the lowest temperature of 28-34 µmol m-2 s-1 while the PN for the highest temperature treatment was 50-60 % lower. We detected a gradual decline of about 1 P N unit per 1 °C increase in temperature. Maximum transpiration rate (E) fluctuated between 0.36 and 0.54 mm h-1 (≈5.0-6.5 mm d-1) for the high temperature treatment and the minimum E fluctuated between 0.25 and 0.36 mm h-1 (≈3.5-5.0 mm d-1) for the low temperature treatment. Cumulative CO2 fixation of the 40/35 °C treatment was 33.7 g m-2 d-1 and it increased by about 50 % as temperature declined. The corresponding water use efficiency (WUE) decreased from 14 to 5 g(CO2) kg-1(H2O) for the lowest and highest temperature treatments, respectively. Three main factors affected WUE, PN, and E of Zea: the high temperature which reduced PN, vapor pressure deficit (VPD) that was directly related to E but did not affect PN, and quasi stem conductance (QC) that was directly related to PN but did not affect E. As a result, WUE of the 25/20 °C temperature treatment was almost three times larger than that of 40/35 °C temperature treatment. and J. Ben-Asher, A. Garcia y Garcia, G. Hoogenboom.
The open neighborhood $N_G(e)$ of an edge $e$ in a graph $G$ is the set consisting of all edges having a common end-vertex with $e$. Let $f$ be a function on $E(G)$, the edge set of $G$, into the set $\{-1, 1\}$. If $ \sum _{x\in N_G(e)}f(x) \geq 1$ for each $e\in E(G)$, then $f$ is called a signed edge total dominating function of $G$. The minimum of the values $\sum _{e\in E(G)} f(e)$, taken over all signed edge total dominating function $f$ of $G$, is called the signed edge total domination number of $G$ and is denoted by $\gamma _{st}'(G)$. Obviously, $\gamma _{st}'(G)$ is defined only for graphs $G$ which have no connected components isomorphic to $K_2$. In this paper we present some lower bounds for $\gamma _{st}'(G)$. In particular, we prove that $\gamma _{st}'(T)\geq 2-m/3$ for every tree $T$ of size $m\geq 2$. We also classify alltrees $T$ with $\gamma_{st}'(T)=2-m/3$.