Study On Root System Architecture And Stress Resistance On Maize Regenerative Plants From Hairy Root Cultures

Regenerative plants from hairy root of Maize (Zea Mays L.)，a new germplasm materialproduced by Maize (Zea Mays L.) Jidan35inbred lines were as plant materials. It grewrapidly, showing more branching roots and lateral roots. Jidan35inbred lines were taken ascontrol. Related morphological parameters such as root length, root number, root/shoot ratiowere analyzed systematically at different development stages. Focusing on systemic and thecomplexity of Maize resistance, drought resistance indexes from the aboveground andunderground part identified by water stress. This research laid a foundation of Maizegermplasm innovation and yield increasing. Study demonstrated that the New germplasmmaterial showed a strong root system, wide lateral root distribution, and high stress-resistanceeven under water stress.The main results were as followed:1. The root length, root dry weight, root/shoot ratio, root activity and layers of Newgermplasm material were significantly higher than Jidan35inbred lines in the whole growthperiod，In addition to the plant height and stem diameter. The root lines of regenerative plantsgrew rapidly, showing more branching roots and lateral roots were reflected fully.2. The growth and physiological activity of the Maize root lines were inhibited ordecreased at different development stages, such as length, diameter, volume, number, tips,area of contour, root/shoot ratio, total absorbing area, active absorbing area and dry weightdecreased evidently under water stress, but the decline of New germplasm material was less.3. The content of chlorophyll (chlorophyll a and chlorophyll b), photosynthesis rate,photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2concentrations,light saturation point, light saturated photosynthetic rate, light compensation point and theapparent quantum efficiency were all reduced at different development stages under waterstress. The decline of New germplasm material was less than Jidan35inbred lines.4. Whole root hydraulic conductivity of New germplasm was0.216×10-7m/(s MPa),Jidan35was0.216×10-7m/(s MPa) under water stress condition was simulating by-0.5MPaPEG-6000. Results showed that the whole root hydraulic conductivity of New germplasmmaterial was significantly higher than Jidan35.5. In a word, growth parameters, physiological and biochemical indexes of newgermplasm declined slightly under water stress. However, compared to Jidan35, varietieswill remain at a relatively high level (p <0.05). The new Maize germplasm with developedroot and intensive lateral root, can support moisture and nutrients well under water stress at developmental stages. Therefore, the New germplasm materials showed lower sensitivityindexes and higher stress resistance.