Cell-wall lectins during winter wheat cold hardening

Young winter rye seedlings, grown and hardened at 1° or 1.5 °C in the dark, developed a high level of cold hardiness at two stages prior to emergence of the first leaf. The first maximum occurred when coleoptiles were less than about 1 mm in length and was followed by a decrease in hardiness. A second and higher maximum occurred when coleoptiles were about 15–30 mm in length (5 weeks at 1.5 °C; 7 weeks at 1 °C) and it was followed by a rapid decrease in hardiness beginning at about the time the leaf broke through the coleoptile. Genetic differences corresponding with those obtained in the field were established by hardening seedlings for 7 weeks at 1 °C and exposure to −15 °C for 16 hours or by hardening for 5 weeks at 1.5 °C and exposure to −14 °C for 16 hours. The use of a lower (−4 °C) hardening temperature resulted in a large increase in cold hardiness at the younger stages of development but little or no increase where seedlings had already reached a maximum of hardiness from exposure to 1.5 °C for 5 weeks. Satisfactory genetic differences were not determined by exposure to −14 °C for 16 hours after hardening at −4 °C. In general the response to hardening of young winter rye seedlings was similar to that found with winter wheat.

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1Selenium supply alters the subcellular distribution and chemical forms of cadmium and the expression of transporter genes involved in cadmium uptake and translocation in winter wheat (Triticum aestivum)

BMC Plant Biology ◽

10.1186/s12870-020-02763-z ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Jiaojiao Zhu ◽

Peng Zhao ◽

Zhaojun Nie ◽

Huazhong Shi ◽

Chang Li ◽

...

Keyword(s):

Cell Wall ◽

Winter Wheat ◽

Subcellular Distribution ◽

Soluble Fraction ◽

Root Diameter ◽

Chemical Forms ◽

Cell Organelles ◽

Cd Accumulation ◽

Yield And Quality ◽

Cd Distribution

Abstract Background Cadmium (Cd) accumulation in crops affects the yield and quality of crops and harms human health. The application of selenium (Se) can reduce the absorption and transport of Cd in winter wheat. Results The results showed that increasing Se supply significantly decreased Cd concentration and accumulation in the shoot and root of winter wheat and the root-to-shoot translocation of Cd. Se application increased the root length, surface area and root volume but decreased the average root diameter. Increasing Se supply significantly decreased Cd concentration in the cell wall, soluble fraction and cell organelles in root and shoot. An increase in Se supply inhibited Cd distribution in the organelles of shoot and root but enhanced Cd distribution in the soluble fraction of shoot and the cell wall of root. The Se supply also decreased the proportion of active Cd (ethanol-extractable (FE) Cd and deionized water-extractable (FW) Cd) in root. In addition, the expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 significantly increased with increasing Cd concentration in root, and the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root was downregulated by increasing Se supply, regardless of Se supply or Cd stress. The expression of TaHMA3-b in root was significantly downregulated by 10 μM Se at both the 5 μM and 25 μM Cd level but upregulated by 5 μM Se at the 25 μM Cd level. The expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 in shoot was downregulated by increasing Se supply at 5 μM Cd level, and 5 μM Se upregulated the expression of those genes in shoot at 25 μM Cd level. Conclusions The results confirm that Se application limits Cd accumulation in wheat by regulating the subcellular distribution and chemical forms of Cd in winter wheat tissues, as well as the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root.

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