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This study aims at investigating the specific ion effects of Na + and K + on Ulva lactuca (L.) growth. U. lactuca was grown in balanced nutrient solutions with 10, 100, 300 and 600 mM NaCl or KCl. The growth was significantly higher at 300 and 600 mM NaCl compared to KCl, with the highest growth rate at 300 mM NaCl. NaCl-treated alga showed increases in the photosynthetic pigments and Rubisco protein content. However, KCl treatments adversely affected these photosynthetic attributes. U. lactuca needs adjusted, but not high K + /Na + ratio for a proper growth, since the high K + /Na + ratio in KCl-treated alga was associated with growth retardation. The cell wall was more extensible at high concentrations of NaCl compared to KCl. Therefore, the deleterious effect of K + could be mainly on the cell wall and hence inhibiting the growth and perhaps the vitality of the whole cell. The transcript of plasma membrane (PM) H + -ATPase was detected only at 300 and 600 mM NaCl, implying that this gene was specifically induced by high concentrations of Na + but not K + . The transcript of PM-Na + /K + -ATPase-like exhibited no Na + specificity and its induction alone could not improve the growth of KCl-treated U. lactuca. The simultaneous induction of the two PM-ATPases could positively affect the algal growth at high NaCl concentrations by maintaining the proper cellular K + /Na + ratio. Also, both PM-ATPases might contribute to energizing the plasma membrane and thereby promoting the cellular growth of U. lactuca at high Na + , but not K + , concentrations., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Most of the hot spots about rice research are related to roots; increasing rice yield is mainly associated with improving root traits. Understanding phenotype-gene regulation relationship in different rice cultivars can contribute to the genetic improvement of root system. The expression pattern of root genes in moroberekan (deep and thick roots and high root/shoot ratio "R/S") was compared to that in Giza178 and PM12 (numerous but shallow roots) and IR64 (fewer but deeper roots than the latter ones). In contrast to the other genotypes, moroberekan did not cease developing deep and thick roots even after 60 days from sowing, perhaps because of not only the consistent upregulation but also the interaction of root genes. Xylem sap flow was significantly higher even under drought (low water content) in moroberekan. Auxin signaling-related ARF12 and PIN1 genes could play key roles in improving root traits in response to low water or nitrogen content. Their concurrent upregulation was coincided with developing 1) deeper roots in moroberekan under drought, 2) thicker and deeper roots in PM12 under low nitrogen content (LN) and 3) new roots with thicker and deeper characteristics in the four genotypes after root trimming. The upregulation of PIN1 or ARF12 in Giza178 at LN, PM12 at drought or in IR64 under drought or LN did not greatly change the root traits. Hierarchical analysis showed that ARF12 and PIN1 were distantly related, but overlapped with other genes controlling root traits. Overexpression of ARF12 and PIN1 could improve root traits in rice cultivars., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)