Influence of Temperature Stress on in Vitro Fertilization and Heat Shock Protein Synthesis in Maize (Zea mays L.) Reproductive Tissues

Abstract

This study was conducted to investigate the response of maize (Zea mays) male and female mature reproductive tissues to temperature stress. We have tested the fertilization abilities of the stressed spikelets and pollen using in vitro pollination-fertilization to determine their respective tolerance to stress. The synthesis of heat shock proteins (HSPs) was also analyzed in male and female tissues using electrophoresis of 35S-labeled proteins and fluorography, to establish a relationship between the physiological and molecular responses. Pollen, spikelets, and pollinated spikelets were exposed to selected temperatures (4, 28, 32, 36, or 400C) and tested using an in vitro fertilization system. The fertilization rate is highly reduced when pollinated spikelets are exposed to temperatures over 360C. When pollen and spikelets are exposed separately to temperature stress, the female tissues appear resistant to 4 hours of cold stress (40C) or heat stress (40°C). Under heat shock conditions, the synthesis of a typical set of HSPs is induced in the female tissues. In contrast, the mature pollen is sensitive to heat stress and is responsible for the failure of fertilization at high temperatures. At the molecular level, no heat shock response is detected in the mature pollen.

Climate Change and Population Growth in Timor Leste: Implications for Food Security

“…Exposure of maize to temperatures C35°C resulted in drastic yield reductions caused by temperature effects on pollination and kernel set. Exposure to temperatures C35°C has been observed to be lethal to pollen viability in maize (Herrero and Johnson 1980;Schoper et al 1987;Dupuis and Dumas 1990). A drastic reduction in seed set at high temperatures has also been observed in rice.…”

Cell Wall Invertase Promotes Fruit Set under Heat Stress by Suppressing ROS-Independent Cell Death

“…It has been well recognized that pollen development and fertilization are more sensitive to heat stress than ovaries and thus the major limiting factors for fruit and seed set under heat stress (Dupuis and Dumas, 1990;Young et al, 2004;Zinn et al, 2010;Lavania et al, 2015). In tomato, for example, fruit set percentage decreased by only 27% when heat-stressed plants were pollinated with control pollen (Peet et al, 1998).…”

“…In comparison to vegetable growth, plant reproductive development including floral development and fruit and seed set is particularly vulnerable to abiotic stresses (Ruan, 2014;Fragkostefanakis et al, 2016). For example, heat stress can cause 80% floral abortion in tomato (Ruan et al, 2010) and seed or grain abortion of up to 88% in rapeseed (Brassica napus; Young et al, 2004) and maize (Dupuis and Dumas, 1990). It has been predicted that the average annual temperature will increase 1.5°C to 5.8°C by 2100 (Zinn et al, 2010), and there will be approximately 2.5% to 16% crop yield loss globally for every 1°C increase in temperature (Battisti and Naylor, 2009).…”

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“…High temperature adversely affects the reproductive phase leading to increased flower abortion, fertilization failure and decreased seed size (Dupuis and Dumas, 1990;Talwar et al, 1999). Similarly, it can desiccate exposed silk and pollen grains on their release from the anthers due to thin outer membranes (Sinsawat, 2004).…”